Conference 7.286::home_work

You might want to try those electric heating cords that are designed to
melt any ice buildup on roofs.

    Ice dams are caused when the snow on the roof melts because the
    roof is warm from heat escaping from the house.  The water runs
    down to the eaves, where is refreezes because the overhang of the
    eaves is not heated from below.  The fix is to insulate the ceiling
    below, so the roof doesn't warm up.  Ways to get around the problem
    include electric heating wires (mentioned in .1).  It also helps
    to put a 3' wide strip of 60# smooth roll roofing along the edge
    of the roof under the shingles when the shingles are put on, so
    there is a solid waterproof layer.  You still get the ice dams,
    but the water can't get down through the roof.  Since nails get
    driven through the roll roofing, this isn't 100%.  A new product
    was shown on the Norm & Bob show (This Old House) specifically designed
    for the purpose; it's some sort of self-healing membrane that seals
    around any nails (they claim) and stays watertight.  
    Another solution you'll sometime see is a strip of aluminum flashing 
    about 2' wide along the edge of the roof.
    Except for the heating wires, none of these tricks are either simple or
    cheap (the wires may not be cheap either!) and none of them help
    much once you've got ice dams.  I'm getting ice dams this year too;
    I'm resigned to waiting until the world thaws out again and then
    doing something.  I'm getting the roof reshingled this spring so
    I can use one of the barrier products along the edge (flashing,
    60# roll roofing, or that new membrane stuff).

    On the addition I just built, I used the Bird Ice & Water barrier
    (membrane). It's about 3' wide and comes in 75' rolls. I found
    it was easier to install it on a cool morning, as it's not as sticky
    and it's easier to line up. as the addition isn't finished yet,
    (no heat) there isn't a big ice buildup on that section of roof,
    I also ran it up the valley of the new roof and the old roof, no
    leaks yet. It's fairly expensive, about $100 a roll.
    
    
    
    Royce

    It's sort of comforting to know that others are having this problem
    too.  I discovered it in my house a couple of weeks ago, when I
    went into an unused bedroom to get the vacuum cleaner.  The steps
    I took to try to alleviate it until things thaw were:
    	1) open the dampers to the heating ducts for the bedroom, since
    the bedroom is on the north side of the house, I figured that this
    would help keep the stuff liquid long enough to runoff.
    	2) shoveling some of the white stuff off.  Unfortunately, I
    haven't been able to keep up with it, and the problem is back.
    
    Rich

You gripe about not being able to find a note about this subject using the 
keywords, and then don't add a keyword to your own note, so people can find it 
in the future.  All it takes is "ADD KEY ROOF".  To find out what keys are 
available, type "SHO KEY", or to find the keywords on a specific note, use 
"SHO NOT /KEY".

Paul

I just bought my house. It was built in 1955 and has not been re-roofed since.
I came from California and had heard of "ice dams". I thought they were just the
exclamations of skiers when they hit a patch of glare ice (which doesn't exist
on California slopes, of course). My house has a significant eaves overhang and
I became thoroughly acquainted with these ice dams when I discovered ***HUGE***
icicles dripping from the very ventilation ducts and louvers that were supposed
to prevent this sort of thing. Wonderful thing this New England... as soon as I
move here we get the worst winter in years! Couldn't have waited until I got the
roof re-done... no... that would be too easy...

So I'm stuck with these tons of ice on the eaves until it thaws, I suppose.
Thanks all for the information though... I'll be keeping in touch when
re-roofing time comes.

Re: .5

	Well, actually I wasn't griping, I was just putting in an 
explanation to avoid the dreaded "See note nnn... why don't people look 
before asking?" reply.  But youy are correct, after adding the note, I 
didn't think to key it.  These things happen.  Now it's keyed to ROOF 
and will show up for searches based on "ice" and "dam" and "ice dam."

Re: .2
	We have a goodish amount of insulation up there now, which may 
be why we didn't have the problem before.  For the interim, I'm thinking 
of putting an attic fan up there to suck the warm air out and move the 
cold air in.  I'll post the results (if any.)
						>>>==>PStJTT

    Regardless of how much insulation you place above your living
    space, there is always *some* heat that escapes upwards into
    your attic.  The real key is to have the entire roof ventilated
    to allow free movement of cooler air under the complete roof.
    The gable vents are a good start - but the biggest culprit of
    ice dams is non-ventilation near the eaves.  On older houses, 
    very little ventilation was put on or near the eaves, so the
    warm air in the attic never escaped from these edges, causing more
    melting, and thus seepage into the attic, under the shingles,
    and even through the "few" eave vents that might exist.  In
    our fairly new house, we have what are called "starter strips".
    These are metal strips put at the bottom edge of the roof, that
    connect the roof to the facia boards - this connection is something
    like a furnace vent (metal with holes in it) - and it runs the length
    of the roof.  What this essentially creates is a separation of
    the house from the roof - allowing air to freely pass under the
    entire roof - no icicles, dams, or anything, even in this winter!
    
    Now - what to do if you've got ice dams today.  First, if you
    home appears to have adequate ventilation at the eaves, get
    into the attic and see if insulation is blocking the air
    ventilation.  If there is no blockage, and dams are still
    building up, you have to take one of the steps outlined in
    previous replies to this note.  My parents have used the
    heat wires, and have had no problems since using them - although
    you can make some pretty long icicles that way.
    
    If you find you have some bad problems today, and serious
    water dripping, your only solution is to manually make drainage
    cuts through the ice dam to allow the water to pass.  Unfortunately,
    the only way to do this is to get an extension ladder, go to the
    roof, and chop drainage paths through the ice with a hatchet, or
    other such tool.  And try to pick a nice day to do it - I can
    remember many a rain storm in Jan or Feb that filled the roof
    with water behind the ice dams, and here's good ol' Andy up
    on a 24' ladder in the driving rain cutting holes in the ice
    to save the roof from collapse......
    
    Just some thoughts,
    Andy
    

    We had water comming in my son's room, so up on the roof I went
    and shovled the roof about four feet in (I hate going on roofs,
    I wouldn't go up with the building inspector on a nice sunny warm
    day and a dry roof). The water stopped comming in. My wife's uncle
    uses a "snow rake" to remove snow from his roof. Does anyone know
    where to buy one of these things?
        
   	Snow Rake:                   /\
    		   metal blades ->  /||\
    				   / || \
                                  /  ||  \
    				     ||
    				     || <- handle
				     ||

    Ed

re: .9

Snow Rakes are available at Spags or Summerville Lumber.  Any good
hardware store should have them also.

    RE: ?  (I forget which ones)
    
    Contrary to the comments about heat escaping and Ice Dams,  I have ice
    dams on the roof of my unheated garage that are MUCH larger than on
    roof of my heated house!  Explain that one. 
    
    Also, if you need some exercise and would like to shovel some snow
    off of the roof..... (I did the front of the garage once, 'cause
    water was starting to run down the outside walls and I figured it
    wouldn't be long before it made it inside. Wouldn't have been too
    bad if the first inch or two weren't frozen).
                                               
    -Bob

    RE: .11
    
    It is unusual for an unheated garage to have larger ice dams
    than a house, but there are possible reasons for it.
    
    Usually, an unheated garage has little or no insulation, except
    maybe some in the walls.  That means ANY heat that may be in the
    garage goes right to the roof.  And if you park your cars in the
    garage when you come home, the heat from the cars has to go somewhere,
    right?
    
    Another reason would be the absorption of heat by the roof
    shingles.  Even though the roof is snow covered, a certain
    amount of heat is absorbed by the roof when the sun hits
    it during the day.  Since unheated garages, etc, usually
    aren't ventilated well, the heat radiates inside the roof,
    and stays there.  It causes some melting of the snow, and
    runs down the roof.  It hits the colder overhang and instant
    ice is the result.
    
    I'd imagine if you put a thermometer near the roof inside
    of your garage, you'd find it was above freezing, and the
    bottom (floor) level of the garage would be colder.
    
    Just some thoughts - My dog's house even has a mini-ice-jam
    on it today!!
    
    Andy
    

      So I'm not alone eh??? I went into my bedroom the other night
    to a drip..drip sound also. The sill has about an inch of ice 
    and stilagtites are hanging from my soffit vents on the dormer
    and a mound of brown ice three feet thick on the porch roof below!
    It is the first time this has happened and its rather depressing.
    I would really hate to see my new cielings and walls get ruined.
    The attic is properly insulated but when I go crazy on the homestead
    this summer, I will use that new $100.00 rolled stuff and add more
    vents. Would gutters help out at all with the ice problem?

    Gutters could make things work.  If your roof is prone to jamming,
    then the gutters will fill up and cause an even worse backup
    of water.  If you put gutters up, and have a jam problem, make sure
    you use the heating coils on the roof AND in the gutters to make
    a full-flowing system.

    re: .13
    
    I juat noticed that some of my icicles are brown, too.  Any thoughts
    on why?  (I'm sure that whatever it is, it'll cost $1000 to fix
    it.)
    
    -joet

  Re: .15

  Do you have a woodstove?  The brown icicles on my house are all on the
  side that has the woodstove chimney.  I always figured that the creosote
  buildup washes down the chimney, onto the roof, and into the icicles.

  If you don't have a woodstove, I suspect a warped or bent A-frame, which
  should cost at least a million dollars to fix...

  JP

      I think the reason I'm getting brown icicles is because the ice
    is backing up under the shingles, through the wood and then  down
    through the soffit vent. On a 70 year old  house I would  imagine
    everything up there is pretty grungy.
    

    re .*

    We had ice damns(sic) several years ago bad enough to require the
    replacement of a ceiling. Ice forming on the wall of the house is a 
    good clue. Bought ice damn (sic) cabling at Spag's for well less
    than half what it cost anywhere else (forgot the price). Lots of
    watts.
    When buying ice cable -or whatever its name is- bear in mind that
    the length of roof it is SPECed to cover typically assumes there
    is gutter also. I ended up with a lot extra. No harm just ran it
    up the cheeks of the dormer but it cost more and consumes more
    electricity.
    It is kind of late for a snow rake for all the snow we have already
    received in New England because many of the damns(sic) are already
    very deep. Hard to rake the snow over the existing damn.
    Until the cabling can be installed, y'all might consider removing
    the damn if accessible. (We are fortunate in that the front roof
    of our cape is only about 10-12 feet off the ground so going up on
    a ladder in the winter is not very hazardous particulary since there
    is a couple of feet of snow on the ground)
    I found that a small sledge hammer broke the ice very effectively.
    (actually tried a blow torch for a while and got nowhere :-) 
    
    
    			fwiw
    			herb

    re: .16
    
    Yes, I do have a woodstove, and yes, it is on that same side of
    the house.  Good detective work!
    
>    If you don't have a woodstove, I suspect a warped or bent A-frame,
>    which should cost at least a million dollars to fix... 
 
    ...and that's just the labor.
    
    -joet

    How about clearing the snow off as much as possible and using rock
    salt? The ice buildup should keep the salt from rolling off and
    it might loosen the ice enough to help break it off the roof.
    I'm not crazy about using too much salt and what it might do to
    plantings, ground water, etc. It might be safer than torches or
    spending too much time high on a ladder with poor footing.
    
    Ever since I noticed the ice forming I've been looking at all the
    houses around the area. Almost all of them have the same problem.
    I have soffet vents and can see daylight at the eves and the problem
    still occurred. My neighbors don't have the vents and you can notice
    the buildup of icicles which I don't have. I wonder how much of
    this problem was caused by the sleet and freezing rain that went
    along with some of the storms?

    When the first real thaw starts I'm sure will see a bunch of notes
    on ceiling and wall repair.
    
    Has anyone made a home built snow rake with a very long handle?
    Seems like a real tradeoff between handle length and material and
    weight on the rake end in order for it to work well without bending.
    
    Nick

    Ice dams are an *almost* inevitable consequence of snow
    and low temperatures. Big ice dams are an *almost*...
    The damn snow is going to melt willy nilly in the day time in the
    sun -no matter how well insulated and cold the attic is. If the
    "ambient"air temp is below freezing the liquid is going
    to freeze as it gets near the edge of the roof. It is this combination
    of melting and freezing that causes the dams. Every several years
    southern New England has the combination conditions we have now, a
    series of storms resulting in a heavy snow cover coupled with 
    no warm weather for the snow to dissipate. Northern New England
    has these conditions much more frequently which is why -i believe-
    as you drive north you see so many more roofs with the 3 ft square
    alumninum/sheet metal "snow guards" on the edges of roofs; and you
    even see tin roofs! 
    As somebody said earlier on, come heavy rains if the ice dams aren't
    gone there will be hell to pay in an awful lot of homes. Sweeping
    off or raking off as much snow as possible will help prevent melting
    snow from making the dams any bigger. In addition, efforts should be taken
    -if possible- to get rid of the dams before a possible heavy rain.
    Come warm weather, worry about appropriate *permanent* measures to
    prevent water from backing up under the roof shingles. 
    
    			a sadder and wiser southern new englander
    			herb

    I *thought* I heard that Spag's had snow rakes, but when I was there
    yesterday I forgot to look.  Would anybody else know, one way or
    the other?
    
    Dick
    

    I have an ice dam (and the associated leak into my house) above
    a skylight.  I guess I'm going to have to put up the electric 
    cabling above the skylight.  Is there any fire danger with those?
    Also, where do I plug it in?  Do I have to have an extension cord
    running down the side of my house?
    Where at spags is the cabling?
    

    We have two 75' (i think) cables. The cables come with their own
    ~10ft electric cord manufactured on to the end. The electric cord
    is labeled 18x2 (not the snow cable part). Both terminate close
    enuf to our bedroom window so no extension cord is necessary. Perhaps
    some electrical types could comment on the best way to use an extension
    cord. And also on potential fire hazard in general! 
    A hair dryer plugged into the same 15amp circuit the ice cables are
    plugged into results in a blown fuse.
    Don't remember where in Spags to get them, but electrical dept.
    is a good guess. In any case they would be able to tell you where.
    

    Regarding the electric heater cables:
    
    > Perhaps some electrical types could comment on the best way to use 
    an extension cord. And also on potential fire hazard in general! 
                 
    Could someone?                       
    
    Also, how do these attach to the roof?  I assume you don't nail
    them thru shingles!
                             

    The cable comes with a pkg of sheet metal "attachments". The
    "attachments" are nailed to the shingles. The cable
    can probably be connected more than one way depending on manufacturer.
    Ours have a kind of hook on the end (perhaps a "?" upside down gives
    a kind of picture) My friend who installed the
    cable for me, took the additional step of
    bending the hook back with pliers to close the loop in the "?" so
    the cable is securely fastened to the attachment
    

    The clips for the cable are sometimes flat aluminum stock bent in
    a "J" shape. When I installed these on my parents house years ago,
    I positioned the clip such that it stuck out from under a shingle
    with the "J" part exposed. I pried up the shingle, nailed through
    the top of the clip, gooped up the nail head, and then pressed the
    shingle back down. Position the wire in the "J" part and squeeze it
    shut with pliers.
    
    For the plug end... I drilled a 1�" hole up into the soffit, passed
    the plug end thru and pull the excess plug wire into the actic. Seal
    the hole with a cork or wood plug with a groove filed in the side for 
    the cord. In the attic, I installed an outlet that that operated
    from a switch located on the first floor. Then the wires could be
    turned on and off as needed.
                                                     
    As for locating them in Spag's, believe it or not, I think that
    the are in the FISH & TACKLE department!
    

    My house came with cables when I bought it many years ago.  I have
    since removed them.  Mostly because they failed open.  The last
    time I had ice problems was in '77 I think.  Since then I have removed
    18-24 inches of snow from the roof edge.  No more problems.  That
    seems to let the sun melt any ices that forms so any meltwater that
    runs overnight doesn't build up more than an inch or so.  Then it
    melts the next warmish day.
    
    Re: Attaching cables:  I found the clips protruding through the
    shingles above the granules.  I didn't like that so any time I found
    one dislodged I flattened the prongs that go into the shingle and
    stuck them under the shingle with plastic roof cement.  Held fine.
    
    Marty
    

It seems to me, that if you want to remove the Ice Dams on your roof, and you
don't have any roof leaks yet, that the easiest way to remove them would be to
set up a hose to spray water on them on a sunny day.  The water would slowly
melt the ice and snow away.  Of course this could mean a lot of water, so it'd
probably help to have gutters, or a good way to drain all that water away...

Jim. 

    On extension cords for heating cables (or general case):
    
    Your heating device (or whatever) should be marked with either
    the current it draws, or the wattage.  In the latter case, divide
    by the voltage rating (I'd be cnservative and use 110 if it doesn't
    say) to get the current in amps.
    
    A 10-foot cord in the next room is marked for 10 amps; it looks
    like it's 18-gauge.  Seems a bit small for that amount of current,
    to me.  I vaguely remember seeing a table once (on the packaging
    of a good-sized outdoor cord?) that said something like:
    
    amps  	18-ga. 		16-ga.		14-ga.
     10		10' or 15'	 ~50'		~100'
     15		forget it	 ~25'?		~50'?
     20 -- if you need 20 amps, better talk to somebody who *knows*
    
    Sorry it's vague, but I don't have anything here handy.  I'd think
    that 16 gauge will probably be enough;  do make sure that it's
    an "outside" cord if it goes outside (the "inside only" ones I wouldn't
    trust  outside except maybe on a clear summer afternoon).
    
    SPAG'S has cords at a reasonable price.  The "inside only" are in
    electrical, up against the wall;  the "outside" kind are around
    the corner, on the bottom of the ramp.
    
    Bring cash.
    
    Dick
    

     I borrowed a snow-rake from a friend this weekend and raked off
    ~3 feet of snow...already it has helped. he bought it at Spags
    for ~$19.00.
                      /BB

>         I borrowed a snow-rake from a friend this weekend and raked off
>    ~3 feet of snow...already it has helped. he bought it at Spags
>    for ~$19.00.

       How long is the handle?   Or do you buy extensions for whatever
    length you can lift?
    

I don't think the gauge of the extension cord will matter much for these 
heating cords.  The reason that cords are rated for certain distances at 
certain amps is because of the voltage drop, and resulting overheating and 
burnout of electrical motors.  The heating cord doesn't much care what voltage 
it gets, and can't be harmed by low voltage, though it may be less efficient.

Paul

    re: how long...
                     this particular rake had (4) five foot sections.
                    I'm not sure of you can buy extra extensions.

re .33:

Sorry, Paul, but that's dangerous advice.  True, voltage drop won't hurt 
the heat cable, but it may burn your house down.

Voltage drop occurs in a too-small-gauge extension cord because the
electricity that won't "fit" through that skinny wire is dissipated as HEAT
- heat that can melt the extension cord's insulation and start a fire. 

In the heat cable itself, that's good - the cable and its plastic jacket 
are carefully designed for that very purpose.  In the extension cord you 
use to power the heat cable, that's very bad indeed.

The safest arrangement is given in .32 (or so); run the plug end of the 
heat cable into the house, and plug it directly into an indoor outlet
strung for the purpose.  (An outdoor outlet would be about equally safe).
No extension cords at all.  The outlet, in turn, should be wired according
to the NEC and any local codes; if you don't know those rules, don't do the
work yourself.

    I spent much of yesterday using a snow rake my father bought at
    Spags. It had 4  five foot extensions. Any more than that and I
    think it would be very hard to handle. It wa easier to work from
    a ladder, (2 stories) than try to use all four extensions.
    
    Also there was a house fire in Shrewsbury over the weekend cause
    by heating wires. I don't know the details, but be careful using
    them.
    
    Mark

re:34

You're right, of course.

Re: 736.6 -- Saga of transplanted Californian battling the ice damns continues

I spent some considerable time yesterday (Sunday, 01-Feb-87) exposing the ice
damns on my house as per the invaluable advice contained in this discussion. I
learned several things:

1) Sunday was a nice day (in comparison to the last couple of weeks) warm at 32
degrees, sunny, and no wind. A perfect day for climbing up on the roof!

2) You should have a ladder to get to the roof. (Remember I am a transplanted
homeowner, and my "yard stuff" {like ladders} is still in storage.) Fortunately,
a stack made of redwood picnic table and benches sufficed to get me to the
proper elevation to hoist myself up.

3) There was *a lot* of snow up there, depthwise! Furthermore, the top two
inches was pretty crusty. A snow rake long enough to be manipulated from the
ground would never have had enough mass to crack this layer. I guess eternal
vigilance is the modus operandi when using snow rakes.

4) There was *a lot* of snow up there, square-feet-wise! My roof is considerably
larger in area than my driveway (thank heavens). I opted to expose only that
portion of the roof that was over the eaves and not try to clear the entire
roof. Some of the previous discussions have indicated that this expedient may be
efficacious. I will report my results. I made no effort to cut channels, but
merely removed what could be pushed off with a pusher-type shovel.

5) Shoveling a roof is easier than shoveling a driveway. Gravity works for you;
just push it to the edge and *poof* it disappears! No huge mounds to have to
heave it over.

6) Footing was no problem. The ice damns tend to be crystally snow, which
afforded quite good traction to my L.L. Bean "Maine Hunting Boots". ("Lounger"
model pulls on, no laces, no muss, no fuss; great for running out to get the
paper in the morning. Not so great {at least without gaiters} in deep snow --
see (3) above.) Note however that my house is 1 story (2 story exposure at one
end) and I might be much less brave about this operation from another story up!

7) The view from atop my roof was quite nice; red sunset, etc.

    I JUST HAD AN ADDITION PUT ON TO MY HOUSE. WHEN THEY FORGOT THE
    SOFIT VENTS, I TOLD THEM THEY BEST BE ON THE GOD DA*! HOUSE IF THEY
    WANTED THEIR FINAL CHECK. WELL WITH ALL THE SNOW THIS LAST COUPLE
    OF WEEKS, THE VENTED SOFITS HAVE MINOR ICE DAMNS COMPARED TO THE
    OLDER PART OF THE HOUSE THAT DOEN'T HAVE SOFIT VENTS. 
    
    I ALSO NOTICE MY ICE DAMS ARE WORSE WHERE THE DRYER VENT EXITS OUTSIDE.
    I GUESS SOME OF THE HEAT IS GOING BETWEEN THE WALLS REGARDLESS OF
    THE INSULATION. THIS ALLOWS ME TO GET A GLASS OF WATER FROM EITHER
    MY KITCHEN FAUCET, OR THE WINDOW FRAME BEHIND IT!
    
    
    
    WHY DON'T THE MAKERS OF THAT 3 FT FLASHING PUT A TEFLON FINISH ON
    THE SURFACE. THAT WAY ANY BUILD-UP COULD BE DISPOSED OF WITH A GOOD
    WHACK OF A BROOM HANDLE. 
    
    ON THE ONCE OF PREVENTION THING, IF YOU HAVE A HOUSE DESIGNED, MAY
    SURE THE ROOF HAS LOTS OF PITCH IN IT, THAT WAY THE SNOW SLIDES
    OFF INSTEAD OF HANGING AROUND WAITING TO SPOIL YOUR WINTER WEEKENDS.
    
    P.S. GUTTERS ARE THE PITS FOR ICE DAMS. I ONLY INSTALLED THEM OVER
    MY DOORWAYS, BUT THEY STILL CAUSE PROBLEMS. WHEN I RESHINGLE NEXT
    YEAR, THE GUTTERS ARE GONE AS I'LL TRY AN INVERTED "V" MADE FROM
    SOME FLASHING. 

    We have a Deck House, which has 2' overhangs and a shallow-pitch
    roof. After some ice dam problems about ten years ago, we had
    roof rolls put up (the roof needed redoing anyway) for six feet
    back. (Shallow pitch needs more.) Seems to do the trick very
    nicely, though (paranoid that I am) I'm planning to shovel off
    a bunch of the snow anyway. It's just nerve-wracking looking
    at fully 3' depth of snow sitting on the roof...

    My old house had major ice dam problems so when I built my new house
    I checked into prevention and found as a previous reply mentioned
    that ventilation was the best prevention.  And the best way to
    ventilate is with a combination of soffit vents and ridge vents.
    A study by a western university found that gable end vents and stack
    vents do not keep the entire roof at the right temperature, that
    being the same inside as outside, to prevent ice dams.  Since then
    I have had no problems and I have noticed that my friends who are
    builders have used this system on all new houses they build.
    
    Ridges vents are inexpensive and easy to install.  The go on instead
    of the shingle cap and 1 inch of seathing is removed from each side
    of the ridge beam.  If this system is used in your house and you
    are finishing off the upstairs, then you must use something to allow
    the air to flow up the rafters.  I used styrafoam channels and I
    noticed again that good builders use them in such places as family rooms
    with cathedral ceilings.
    
    Someone mentioned using a hose and water to melt ice dams.  Back
    when I had them I used that method but hooked the hose to the washing
    machine hot water hookup.  It works faster and does not damage
    shingles.
    
    Anyway, it's better to treat the problem than the symptoms.

I've been following this discussion with much interest.

When I built my addition (32' x 32', two stories), I wanted to make sure ice 
dams were never a problem-- 18" overhangs, fully vented vinyl soffits,
full ridge vent, 1" gap min. over roof insulation.

I have some dam build-up that I can see from the ground but it appears to be
only an inch or two thick. So far everything is ok but a question occurred to
me-- What happens to the ventilation when the ridge vent gets covered with
snow?  Any air circulating through should be the same temp as the outside air
so that's not going to melt the snow from around the vent.  Should we be
shoveling snow from around the vent to insure circulation?  Is a snow cover
porous enough to allow sufficient air circulation? 

Whaddya think?

						--Mike

Just a guess, but I would think that if the ridge vents got clogged with 
snow, then heat would build up at the high spot in the roof (the ridge) 
and wuold melt the snow, then dissapate because of the draft caused by 
the (now unclogged) ridge vent.
					>>>==>PStJTT

re .43

Yes...if the snow gets too deep (as it was on my place) it WILL cover 
the ridge vent. I didn't have any problems with ice damming 'till the 
vent got covered. Fortunately, I discovered the icicles (sp??) coming 
from the soffit vents before any serious damage had been done. I've 
since cleared the vent off and shoveled the snow from the edges...

    
    Well this Sunday, I too got up on the G*D* roof to tend to my ice
    damms.  I have a rood with a low pitch, a large (about 36") overhang
    with soffit vents and two gable vents.  Problem for me is that the
    ice damm occurred on the northest side, which is also the side that
    I turned into a master bedroom *complete with vaulted ceiling*.
    I added 6 1/2 inches of insulation between 2x8 rafters, and I put
    styrofoam channels between the insulation and the sheating to force
    air flow and ventilation.  I also (this summer) added a gutter to
    protect the patio off the bedroom, but I think the gutter is going
    to go this Spring, since when the dam started, it started with the
    year's fist snow inside the gutter, then just kept going right on
    back.  I wound up melting the gutters with a hose connected to the
    hot water from the laundry faucet, and adding heatinfg wires, but
    the damn dam just kept getting bigger with each successive snow.
    Saturday when I started to see icicles forming on the soffit vents
    (apparently the water made its way into the roof over the overhang,
    then was diverted to the vents through the styrofoam channels) I
    decided it was time to get snow off the roof and remove the dams.
    Luck was with me, as the sun was out, so as soon as I got about
    four feet of snow off the roof (from the eaves on back) and chopped
    a few channels in the dam with an axe, I was able to dislodge the
    remainder of the ice dam with the shovel, as the heat hit the roof.
    
    I noticed a few things though; my roof shingles are on their last
    legs, as they are almost smooth over the soffit, so I think reroofing
    and a permanent fix is in order this spring.  Questions are:
    
    1.    Should I install a ridge vent over the portion of the roof
          having the vaulted ceiling?
    
    2.    Should I run a few courss of roll roofing over the bottom
          of the roof in place of the starter courses of shingles? 
          If I used roll roofing, I'd be sure to tar all the nails and
          seams, or would I be better off using the metal ice belts?
    
    And, the gutter was a good idea for the patio garden in the spring,
    but it's gotta go ! ! !
    
    Thanks,
    
    /Dave
    
    

    Well, the time has come to do something about the snow on my roof
    too.  To the local hardware store to buy a snow rake...  NONE to
    be found.  I have now called all over the Nashua area and I can
    not find one.  So, I need your help for one of the following...
    
    1) Does anyone know a place that has snow rakes in stock??
    
    2) Does anyone have one that they would be willing to lend out for
    	a couple of days??  (I work in ZK and live in MK)
    
    3) Has anyone tried making their own???  (long handle + board +
    	lag bolt = snow rake???)  I am planning on getting onto my roof
    	and pushing, so the weight is less important than if I were
    	working from below..

    4) Do I just go up with a shovel.....
    
    Thanks,
    jeff
    

As a suggestion, I think you should install the ridge vent over the 
entire house when you re-roof...that's what I did and it seems to work 
VERY effectively... Installing a ridge vent is extremely easy especially 
if you've got the roof down to the sheathing.

The more venting, the better...BTW, I've a low pitch roof also and 
that's why I had the problem after the ridge vent got covered with snow. 
When I get a chance this weekend, I'll get back up and finish the 
shoveling job since the ice dams are slowly going away with the warmer 
days...

Chris

       I would imagine that it would be fairly easy to build a sno-rake
    out of the light weight telescoping aluminum poles like the ones
    used for hand pool skimmers. That and an 18"x10" piece of sheet
    metal might work nicely!
    

    I simply taped a garden rake to a long 2X2 I had lying around. 
    It worked pretty well.  It didn't clear things down to the shingles,
    but it got close enough that the sun took care of the rest.  Next
    year, I'll be using it after each snow so that the problem doesn't
    get big to start with.  By the way, I cleared only the last foot
    or so of shingles.
    
                                                August G. Reinig

    A few replies back about shingles being worn reminded me that another
    goodness obtained from ridge vents is a lower temp in the summer
    and therefore a somewhat longer life on shingles.  That according
    to Bird and Son.  Heat is a major factor in shingle deteriation.  

    Well fellas and girls it's getting to be that time again. I would
    like to put in a plug here for a method of preventing damn dams
    that has only been touched on before.
    
    When I did such things for a living, I put up a fair number of Ice
    Panels. These are square aluminum panels with a raised center.
    They lock together and replace the  first N courses of shingles.
    The raised portion moves in response to temperture changes and
    breaks up any ice that can form. They are better than the cables
    'cause they don't heat and deteriorate the shingles, they work
    even if you're not there, and they don't use any energy. When combined
    with soffit and ridge venting you should have 0 problem. they do
    have one drawback, however, they're rather ugly. If you have a 
    shallow pitched roof, say 5 or 6, they are not easily visible so
    that shouldn't be much of a problem.
    
    Alan

    Can they be put directly on top of existing shingles?
    Or are they installed as part of a reshingling job

    re: .52
    
    	Good question. When I was doing it they were always part of
    a re-roof. This did include, however, a couple of 2nd layer jobs
    where they were put over the old shingles. I believe that they
    include a built in drip edge ( but, this was 9 years ago so my
    memory is a bit hazy ) so you might be able to strip just the
    bottom course (or none at all) and work them under the existing
    shingles sealing the joint with roofing cement. 
    
    	The process we used was a doubled layer of 30# felt at the
    eaves with succeeding courses lapped by approx. 1', then the ice
    panels were given a coat of roofing cement on both sides of their
    top edge as they were installed. The first course of shingles
    was doubled just as you would over conventional drip edge.
    Never had a leak that I know of, of course the guy I was working
    for believed in doing things right the first time (probably why
    he went broke :^( 
    
    Alan

    My wife just called me and said the bedroom ceiling is leaking
    along the out side wall.  I've heard of this happening and I think
    I know what is happening on the roof to cause this.  What can I
    do to stop the inside leaking?
    
    						Thanks,
    
    						John

    	Is there snow on the roof?  If you are in a winter climate then
    this sounds like an Ice Dam.  Did you clean the gutters lately?
    The best suggestion I can make is to chip the ice off the roof and
    from around the gutter.  You can get an electric heating cord that
    will clip to the roof to prevent future ice dam formation.
    
    					=Ralph=

    After the problem is corrected, I suggest you check the attic to
    see if the water did any other damage. If it soaked the insulation,
    you may want to replace it. Also, if it was an ice dam, try to correct
    the problem permanently, because in the long run, the moisture
    collecting will do more damage, both cosmetic and structural, plus
    make a great environment for insects (I found my hidden carpenter ant
    nest in a eave where an ice dam had caused moisture damage).
    
    Eric
    

Also, look for the note titled "Ice dams". There were a lot of replies 
on the subject last year.
					>>>==>PStJTT

    This may sound like a DUMB question but when to you plug in the cables?
    While its snowing, before it starts or after it stops?
    
    
    						Bart Lasky

    The cables consume SCADS of electricity. There is ABSOLUTELY no
    point in plugging them in before there is snow on the roof. I doubt
    if it is ever necessary to have the cables running for the entire length
    of a storm, but that should be some kind of an upper limit. As a
    first approximation, plug it in after it has been snowing for a
    couple of hours, and see how the cable keeps up with or ahead of
    the snow

	The cables can be turned on anytime after the storm is over and
should be left on only long enough to melt channels clear through the dam.
It is often mistakenly thought that cables are used to melt the entire dam,
this is not true.  They are used to create openings through which melted
water can be shed from the roof, relieving any pressure that would build 
otherwise.  This prevents a large dam from forming and the subsequent backing
up of water under the shingles.  

	I have an area of my roof that is particularly suseptible to damming
but since I installed cables I've had no problem.  After a heavy snowstorm I
turn the cables on for about an hour and that does the trick.  I have had no
damming since their installation. 

							--Mike

    If you use Frostex II cables, you can leave them on all the time.
    They draw energy only when they are cold, and then only enough to
    warm themselves up again.  They are quite efficient and
    self-regulating.
    
    				Steve

How about properly ventilating and insulating the attic so that ice dams won't
be created in the first place?

(or are we talking about houses that use the area directly under the roof
as heated living space, like capes, some contemporaries, etc?  I used to
having a full, useable walkup attic)

Steve

I have a roof with a  5/12 pitch and 18" overhang.  The attic is well insulated
and ventilated.  Snow still builds up  and,  on  the  North  side,  a  dam will
eventually grow up well over 2'.  My  solution was to put in the wires.  

I did not like the idea of  plugging  in  the  wires (and remembering to unplug
them later) every time it snowed - I like staying indide when it snows.  So....
I ran lines to the front and rear of  the  house  through switches mounted in a
closet to outlets in the underside of the front and  rear overhangs at the ends
so  I  could  permanently (with caulking around the plug) plug in  the  heating
wires.  The switches are the kind that have red lights to  indicate  on.  Now I
just switch on whichever wires I want and not forget to turn them  off  since I
can readily see if they are still on.

Dave

>< Note 736.59 by MAMIE::DCOX "Try? Try not! Do, or do not." >
>so  I  could  permanently (with caulking around the plug) plug in  the  heating
>wires.  The switches are the kind that have red lights to  indicate  on.  Now I
>just switch on whichever wires I want and not forget to turn them  off  since I
>can readily see if they are still on.

Dave,
	Great minds must think alike because that's exactly what I did too.
I went just one step further, though, in that I plug my cables into a timer
which is then plugged into the switched outlet.  That way, even if I forget to
switch off the outlet, the most the cable will run is 2 hrs a day (the min.
time I could program the timer to be "on")

							--Mike

>I have a roof with a  5/12 pitch and 18" overhang.  The attic is well insulated
>and ventilated.  

I don't believe it, a properly insulated and 
vented attic should not have ice dams.

Brad.

>< Note 736.61 by VAXWRK::BSMITH "I never leave home without it!" >
>                         -< Something's wrong here... >-
>
>>I have a roof with a  5/12 pitch and 18" overhang.  The attic is well insulated
>>and ventilated.  
>
>I don't believe it, a properly insulated and 
>vented attic should not have ice dams.
>
>Brad.

That's OK.  You don't HAVE to believe it.  

Since this is a "help your neighbor" conference, I'll see if I can make it more
apparent.  An ice dam initially begins due  to  the  freezing  of  water  as it
becomes exposed to cold air upon exiting the snow  pack  after  it has run down
the roof, under that snow pack.  The melt can  occur  from two events;  melting
from underneath or melting from the sun (melt still trickles down  to  the roof
and runs down to the eaves).  It matters little that a  house  has  R19+ in the
attic floor, if the sun is out and the temperature is near freezing, there will
be melt from the sun.

When I moved  in,  the  attic  was  poorly  insulated, although well ventilated
(gales would blow through).    Most  of  the  exposing roofing nails would have
frost on them and after  every  storm ther would be iciles everywhere.  I added
insulation, effectively tightened up the lower  area  using  a  humidifier  and
baffled the vents to keep the wind  down.   Consequently, the attic maintains a
much lower average temperature - never mind my  heating  bill plummeted - nails
are no longer frosted and the only time I have iciles is when I run the heating
wires.  

Now then, I found it  a  bit  confusing when I had a small (used to have LARGE)
ice dam on the back, north  facing side after all this work.  The reason turned
out to be simple, although not obvious at the start.  The melt from sun melting
was at a lower temperature than the melt from attic heating during the previous
seasons.  That meant that the melt from the  sun  would  tend to freeze sooner;
once anything occurs to impede the dripping of melt, a  dam  will rapidly build
up.  If you climbed up to the attic with me  around  Dec 1 to get the Christmas
decorations, you would realize that the melt is no longer from underneath.

A  down side of a well insulated and ventilated attic, especially on  a  "flat"
slope, is that I now get to worry about the weight of all  that  snow that used
to melt away, but now just piles up higher and higher.

Dave

>That's OK.  You don't HAVE to believe it.  

I wasn't meaning to be wise, I just think you either have poor ventilation
or poor insulation.  From you note, I still can't tell which, maybe R-19 in 
the attic isn't enough.  If your insulation/ventilation is done right, your
attic should be about the same temperature as outside, or not much warmer.
Snow melting from the sun shouldn't build up an ice dam because if it is warm
enough to melt it in the first place, it shouldn't be able to freeze in the 
second place.  *Unless*, the sun is heating up your attic, then you can get the 
ice dams, that would be poor ventilation.  My house has a 4/12 pitch, 12 inches
of insulation in the attic (R-30 or something like that), and continuous sofit 
and ridge vents.  I never have ice dams!  If you have sofit vents, could your
insulation be blocking them??

Brad.

    
    
    		Or how about my case; where the sun warms the roof enough
    to get melting on the west facing side, except where the chimney
    creates a shodow accross the overhange. Add to this a cathedral
    ceiling in the warmest room in the house (wood stove) and 2 skylights
    and you get glaciers.
    
    					...Dave
    

Ok, then how come after a warm day, all of the roof on my house that
overhangs, is usually dry as a bone (you can see the roof) while the
roof that is directly over the house will still have snow on it??
It makes no difference which side of the house it is either (facing sun
all day, North side etc.).  There has to be a better solution to the
problem than running wires and heating sections of the roof to prevent
ice dams.  I think this is an expensive alternative over the long run.

Brad.

    I looked at all the notes concerning gutters and didn't find my
    answer sooooo...
    
    I just hung two 10' gutters over a deck.  I bought a small joining
    bracket to join the two.  I am getting a leak at that joint.  Am
    I missing somthing?  Is the a QUICK fix to the problem?
    
    
    						John
    
    Can I pull the higher level gutter out of the bracket and just slide
    it inside of the other gutter?
    

>        I just hung two 10' gutters over a deck.  I bought a small joining
>    bracket to join the two.  I am getting a leak at that joint.  Am
>    I missing somthing?  Is the a QUICK fix to the problem?

    What kind of gutters?  Raingo?  Aluminum?
    If they're Raingo, did you use the rubber 'gaskets' and silicone?
    

    LEAKY GUTTER
    TRY USING SOME SILICONE SEALER ON THE SEAM, CAN GET AT ANY HARDWARE
    STORE OR K-MART.
    MIKE

    A hardware will have special goop for sealing the seams in aluminum
    gutters, if that is what you have.  It seems to wear out eventually - I
    had to do mine a year or so ago when they started to leak there; they
    were installed 8 years ago.  The goo is grey and is sort of like the
    goo you would use to patch roof shingles around a vent pipe.

    Thanks guys.  I will try the Silicone sealer....that was exactly
    what I was going to do if no one had any ideas.  Its aluminum 
    gutters I put up.
    
    						Thanks again,
    
    						John

    The "right" solution is to build the house with the right pitch
    on the roof and the right ventilation to start with.
    
    Style and costs have changed the general designs of houses such
    that the cost is now incurred by the owner over time and inconvience
    rather than the builder.
    
    /tb/
    

>    The "right" solution is to build the house with the right pitch
>    on the roof and the right ventilation to start with.

The "right" solution is live in the Bahamas....

    Back to roof rakes:
    
    Believing that an ounce of prevention is worth a pound of cure,
    we got a super, doubly conductive aluminum roof rake.  (Doubly
    conductive: it conducts heat away from your hands, and electricity
    right to your hands.)
    
    Anyway, it strikes me that the aluminum plate at the business end
    of the rake can't be healthy for the shingles.  Should we be waiting
    until there's a thicker layer of snow on the roof (thicker than
    the two inches we got last night), or would it make sense to try
    to improve the rake.  I was thinking of installing some vinyl weather
    stripping or even some sponges around the end of scraper.
    
       Gary

    Are you serious about a roof rake?  Or is that some joke?  I never
    heard of one before.  How would it be used and what benefits does
    it have?
    
    Ed..
    

<   Are you serious about a roof rake?  Or is that some joke?  I never
<   heard of one before.  How would it be used and what benefits does
<   it have?
<   
<   Ed..

        A roof rake is very popular up north.  When you get a few feet of
        snow on the roof it must be cleared off or 
                1. icew damms occur
                2. the weight could get to be a problem

        All it is is a 3-6 foot wide scrapper on a long pole that reaches
        the roof.  And you pull the snow off!

        Most  people  around here will  use  them  just  to  prevent  ice
        backups.

    After serious ice damming problems ($3k worth of damage) I purchased
    a roof rake from Spags and it was effective.  Every time it snows
    I rake nearly the entire roof.  I was wondering if I can get away
    with only doing the first few feet, along the edge of the roof?
    I don't want to experiment and find water spots on my ceilings.
    
    Does anyone out there KNOW (from first hand experience) if it's
    necessary to rake the entire roof.  My roof is a 10 pitch, with
    cedar shingles, soffit vents, ridge vents, and loads of insulation
    in the attic.
    
    Phil

	re: .69

       Gary,
       
       I've been using a roof rake for two seasons now and haven't seen
       any perceptible damage to the singles. I suspect that my stomping
       around the woodstove flue while cleaning it has done more to harm
       the shingles than my raking. I leave the small stuff on the roof
       and the sun generally warms it up enough to melt completly. When
       it gets deep is when I rake the edges. 

       Of course, having a well ventilated and insulated attic area will
       reduce the dam buildup. I had trouble the first year in the house
       because the dimbulb previous owner had covered all soffit vents
       and only had one gable vent for the whole attic. Since removing
       the offending insulation and putting in a ridge vent, I've no
       problems with excessive ice dam buildup.

       Chris

    Not from personal experience with roof rakes but I've suffered some
    damage from ice dams and now have them fixed.
    
    You only need to clean off the edge of the roof - back about 3 feet.
    What happens is the heat from the roof melts the bottom layer of
    snow and water begins to run down the roof.  It hits the edge which
    is colder and freezes which builds up to a dam further hindering
    run off which collects building a bigger and bigger dam.  If the
    area which is colder is free of snow then the water just runs off
    and is not slowed long enough to freeze.

You can climb  up  on  the roof and shovel away, then again you could fall down
and be hauled away - as my neighbor did

or.....

You can  buy  a roof rake from Brookstone, for example, for something less than
$50.00.  Then you  stand  on  the  ground (for a 1 or 1+1/2 story) and actually
pull the snow down on  top  of  you.   Wife has GREAT laughs -especially if she
gets pictures of you under the  snow.

or...

You can spend about $50.00 and put up heating wires.  A flip of the switch from
inside gets neat little channels melted in the snow.


An earlier reply detailed what I did with the wires.

Now, if I just had enough money to put in heated_anti-freeze_in_the_pipes under
the driveway.........

Hmmmmm

Dave

    The roof rake we got at our local hardware store was significantly
    less than $50, though it was quite likely more than Spags charges.
    
    With our electric rates, the cost of operating the heating wires
    would soon dwarf the cost of installation.
    
       Gary

    Or you could do as my husband and wang one together out of scrap
    wood.  Just the right thing for getting snow off the top of our
    greenhouse where one must be VERY careful.
    
    	Marlene
    

    RE: .76
    
    You don't leave the wires on all the time. Just to clear the area and
    prevent the initial dam (dam*) formation. I'd rather spend a few
    dollars per year than get hit with a partially formed ice dam from the
    roof height above my head. You don't roof rake all the time so you
    don't have to run the wires all the time either. Think of it as a rear
    window defroster for the roof. Once the frost is gone you can turn it
    off. (although in my VW bug I had to continue to scrape the INSIDE
    windshield ;^)

    Help...
    I've read notes 182, 1633, 1741, and 1917 just to name a few
    and the problem I'm now having is not really discussed.
    I'm new at all this stuff, so bear with me please.
    
    My roof (condo connected to three other units) ridge faces
    east-west. Therefore, one side of the roof never gets direct sunlight.
    Because of this the back side (interior) of my roof has condensation
    like nobodys business. It has started leaking down into a bedroom
    ceiling in a couple of places. It is not actually dripping from
    the roof, but collecting on the beams and running down to the 
    corner where the beams meet the ceiling.
    Now, I do already have soffet vents and a peak vent (whatever 
    that is called) pretty much the whole length of the roof.
    The soffets are clear of insulation and seem to work ok, but
    it needs something more. (The front side is dry as a bone.)
    How can I get this back side dried up QUICKLY and keep it dry?
    Would running a DEhumidifier in the attic help?? A fan???
    How about 37 hair dryers??? :^)
    
    Any ideas greatly appreciated...
    
    Mike
    

    What is insulated the roof or the attic floor?

    
    	RE: .0
    
    	Also, does the insulation have a vapor barrier?  Is it facing
    the heated area?
    
    Is somebody in one of the units venting a bathroom fan or dryer
    into the attic???
    
    Phil

    
    Thanks for the quick response....
    
    The ceiling is insulated. The roof is exposed.
    The insulation is blown in fiberglass clumps.
    The attics are seperated from unit to unit.
    I have a bathroom fan but never use it. (I thought that might be
    a problem if I blew moist air into the attic.)
    I think the main problem is that the North side of the roof
    never gets warmed up.....it's just how do I get it dry?
    
    
    Thanks in advance,
    Mike
    

    
    RE: .3
    
>    I think the main problem is that the North side of the roof
>    never gets warmed up.....it's just how do I get it dry?

    I disagree.  The main problem is that there is too much moisture
    for the amount of ventilation in the attic.  The warmth of the roof
    has nothing to do with it.  I believe you need 1 sf of ventilation
    for every 300 sf of attic (with a vapor barrier) and 1 sf to 150
    sf of attic (without vapor barrier).  What's under those "fiberglass
    clumps"?  Anything that may be called a vapor barrier?  Some paints
    provide a barrier of sorts.  Painting your ceilings with them may
    help.
    
    Are you sure it isn't a leak on the roof?
    
    It's got to be either:
    
    		1) roof leak
    		2) excessive moisture
    			( bathroom, dryer vents, no vapor barrier)
    		3) inadequate ventilation
    			(blocked or inadequate to start)

    
    My $0.02
    
    Phil
    

    
    re: .4
    
    OK.. It is not a leak in the roof. When it is cold, the entire inside
    of the north side of the roof is WHITE with frost.
    
    There is nothing between the insulation and the ceiling. I've cleared
    away a few spots to take a look. Bare ceiling sheetrock.
    Do you think the moisture is coming from the house or from the
    outside?? Is there supposed to be a vapor barrier between the ceiling
    and the insulation???
    If this is the case, would it help now if I put plastic over the
    insulation to keep house moisture from going into the attic??
    
    
    Mike
    

>>    Do you think the moisture is coming from the house or from the
>>    outside?? 

The moisture is coming from the house.  Winter humidity is usually very
low outside (dry polar air masses in the NE) so the humidity in your
house is getting into your attic because there is no vapor barrier.

>> Is there supposed to be a vapor barrier between the ceiling and the 
   insulation???

Yes.

>>    If this is the case, would it help now if I put plastic over the
>>    insulation to keep house moisture from going into the attic??

While that would help keep the moisture from getting into your attic, it 
would also reduce the insulating value of your fiberglas. (wet insulation
doesn't insulate much).

Two alternatives that come to mind...

   - Paint the ceilings with a vapor barrier paint.

   - Lift (shovel, rake, or other) the insulation, put down a vapor barrier,
     and  (shovel, rake, or other) the insulation back.  Not a very desirable
     task.  8-(

Bob

    
    RE: .5
    
    Now we're making some headway!  Your solutions appear to boil down
    to:
    
    	1. If the current insulation isn't to the top of the ceiling
    	   joists then you can shift current insulation, put down kraft
    	   or foil faced R-11 and then top it off with the loose stuff.
    
    	2. Leave insulation as is and increase ventilation to 1/150
    	   ratio.
    
    	3. Paint ceilings with BIN or similar product.

    BUT, since this is a condo you should check to see if the builder
    and/or association is responsible for the fix.  And from the sound
    of it, your bathroom fan is vented to the attic.  You may want to
    get that vented to the roof or soffit.  
    
    Another $0.025...
    
    Phil

    P.S.  I thought condos were supposed to be maintenance free!? ;-)

    OK, here's the deal ......
    
    I called the builder (he's still the association, buildings still
    going up) and got pretty much nothing at all. This I expected.
    I called the town building inspector and he was interested enough
    in my problem to come and take a look.
    His findings were;
    	a.	Bathroom fan vented (or not vented) to the attic.
    		There is a tube coming out of the fan with a flapper
    		and this blow directly into the insulation.
    	b.	Sofett (sp?) vents are covered by the GUTTER!
    		I guess originally this place had no gutters and
    		although it was good for venting, people were complaining
    		that water dripping from the roof was making trenches
    		in the dirt. SO, they just put gutters on over the vents!
    	c.	No vapor barrier. The sleazebags put foil backed insulation
    		(under the blown in stuff) ONLY near the 2x2 entrance
    		so that if anyone (inspector) poked his head through
    		the opening and felt around, he would see the correct
    		insulating method. 
    Needless to say, the inspector was not amused by this. He said that
    it is definitely the builders responsibility to take care of this
    and that he (the inspector) will oversee the corrections.
     I just hope this all doesn't take forever to fix. We'll see.
    
    Thanks for all the info. It helped me ask intelligent questions.

    Mike

    Re: Taking a long time to fix....
    
    I shouldn't take long long at all considering that the building
    inspector is not pleased with the faults and the builder is still
    in the area building new units!
    
    The building inspector could very well issue a stop work order for
    the new units until the builder corrrects problems with the existing
    units!
    
    Charly

    As far as the "only faced insulation being at the 2X2 access hole
    so as to fool the inspector into thinking it's all that way..."
    
    Consider the fact that there is no alternative to this method if
    blown-in insulation is used; otherwise, you'd be greeted by a wave
    of insulation when you opened the access. 
    
    One other point: What kind of gutters can block soffit vents? It
    doesn't make any sense to me!
    
    Also, is there any ridge vent?
    
    Mike (Whose blown-in insulation is also soggy--no vapor barrior
    in a 2-1/2 year-old home!)

    
    RE: .8
    
    From the sound of it, the condo association (if there is one) might
    want to take a closer look at other work this builder does.  As
    .9 points out, NOW is the time to get him.  Once they're gone, these
    types of builders have a tendency to declare bankruptcy and then
    you are stuck holding the bag.
    
    Good luck in your quest.  It sounds like you'll need it...
    
    Phil

    I have been referred to this notesfile in desperation and frustration
    with what might be a similar condensation problem in need of a creative
    solution.  If you think you have an answer, I sure would appreciate
    some suggestions.

    The master bath has had a problem that only appears in late winter
    afternoons on sunny days.  The problem is water dripping through
    eyeball spotlights in the bathroom ceiling.  The ceiling is cathedral
    and of the following construction.

    T-lock shingles w/felt			///////////////////////////
    1/2 inch chipboard				__________________________
    						  ||     _______	 ||
    12 inch (11 1/2 nominal) TGI rafter		  ||XXXXX|     |XXXXXXXXX||
    1 1/2 inches airspace			  ||XXXXX|spot |XXXXXXXXX||
    10 inches Fiberglas batting                   ||XXXXX|can  |XXXXXXXXX||
    						  ||XXXXX|     |XXXXXXXXX||
    polyethylene vapor barrier			  _______|     |___________
    carbon/mylar radiant heat sheeting		_________|     |___________
    drywall (greensheet)			=========|     |===========

    The ceiling runs from 12 to 15 feet high and there are no penetrations
    in the outer roof.  The spotlight cans are deep enough to reach into
    the airspace above the insulation and are not sealed such that I can
    feel cool air circulating.  The TGI's do have holes in the webs that
    allow airflow between rafter spaces.  There is no eaves vents on this
    rafter space from eave to peak.  The roof pitch is 1/3 and north
    facing.

    Well that's the specifics.  I have had a roofer out twice and he has
    mucked around on the roof laying some sealer on the vent pipes which
    aren't even in the same rafter space.  He says the roof is tight and
    I believe him since the lights have never leaked from rain AND there
    is no correlation or need for snow to be on the roof when the leak
    occurs!  Our environment here in Colorado is dry (12% average humidity)
    and I have never had a leak other than in winter.

    The problem might be fixed by adding an eaves vent in the airspace, but
    this would mean exposing the cans, which are not sealed, to the cold
    air and allowing it into the interior.
    
    Has anyone a solution that will not compromise the insulation or
    require tearing out the lights? 
    
    	Chuck

re: .12
    
>    Has anyone a solution that will not compromise the insulation or
>    require tearing out the lights? 
    
      Chuck --

      Based on the diagram and text in .12, my guess is that the problem
      occurs because you have ALREADY compromised the  insulation.   The
      can  for the light goes through the insulation.  This allows warm,
      moist air from the bath to reach the cold underside of  the  roof.
      Or maybe the condensation is occuring inside the top of the "can"? 

      It  sounds  like  the  ceiling  is  high enough that you could use
      surface mounted lights rather than recessed, and that may  be  the
      solution. i.e. remove the recessed lights; close up the holes with
      proper  insulation,  vapor  barrier,  etc.,  and  install  surface
      mounted lights.  Would a section of track lighting look good?

    I don't know much about this, but if you're looking for a mechanism
    which goes along with what .13 says, something like the following
    could be happening to cause more than just "dripping" when you're
    taking a shower:

      1. If the outside temp is consistently below freezing, then the
         inside temp of the sheathing could be freezing (given the good
         insulation).

      2. Steam is pulled through the light can (by heat convection
         initially).  The steam condenses as frost/ice on the root
         sheathing (that's roof sheathing, not in an editor).  Once the
         steam starts condensing, its change in volume requires more
         air to be supplied from somewhere.  You get negative pressure.

      3. Since the path of least resistance is through the light, more
         moist air is drawn through the light and the condensation picks
         up its pace for the duration of the shower/moisture in the room.

      4. When the sun hits the roof, the frost/ice in the airspace melts
         and runs out.  This could be a substantial amount of moisture
         depending on how long the roof was cold, and whether you shower
         while it's dark, etc.

     If you can't change the configuration to eliminate breaches in the
     insulation, here are some other things to consider:

      1. Prevent the free flow of air through the gaps.  Get water-tight
         (and air-tight) fixtures, and caulk them (make sure you don't
         create a fire hazard here.

      2. Try to reduce the flow from the bath to the airspace.  Run a vent
         fan to reduce the pressure inside the room (keep the door closed
         when showering).  Vent the offending airspace to outside.  This
         means you'll be creating a small draft from the airspace into the
         bath, but it might avoid moisture problems which are probably
         more costly in the long run than additional heating costs.

      3. "Warm up" the lights before showering.  Leave them on a while after.
         Might cut down on condensation.

     Of course, if this hypothetical mechanism is not the problem, the
     suggestions won't do you much good...

    	
    The reasoning in .13 (Peter) sounds accurate and would explain
    the draft and the observations.  It does confirm more of my
    suspicion that it is a condensation problem.  I left the lights on 
    all day yesterday and we did not use the master bath shower, and
    it did not leak!

    I would hate to have to remove the lights since they add a
    good deal to the lighting and mood in the jacuzzi tub under
    them (might not find the champagne bottle). I considered the
    track lights, but even in Colorado where there is little in
    the way of building codes, they are not permitted.

    I stopped by a local lighting store and explained the problem.
    The lighting person was aghast that eyeball spots were placed
    in a bathroom, let alone over a jacuzzi tub.  He showed a trim
    ring that could correct the problem.  It is a sealed, frosted
    dome that replaces the eyeball, unfortunately at the expense
    of light and direction.  These will only accept a 60 watt bulb
    and are essentially omni-directional. The are however, gasketed and
    screw down.  These would be one solution, but a 60 watt bulb shining
    through frosted glass 12 feet overhead would not add much light.

    I haven't given up yet.  I'm stopping by the library tonight to
    look through the Architecture Archives on lighting fixtures.
    
    I'll post an update on what I find.
    
    	Chuck

    re:Chuck
    	How about replacing the lights with track lighting?
    
    Question/problem....
    
    A friend was talking to me yesterday about his house.  Seems he
    is getting water leaking from the back of his vinyl siding.  Its
    a cape. 2x6 construction.  He used 2x6x12's with a firestop between
    floors.  The roof is well vented.  6" of fiberglass faced.
    If it keeps up, seems to me that the plywood will rot and fall off
    the house.  He has been told to "stop durning wood" to take out
    the 6" and replace it with 3" of f-glass.  Anybody like to take
    a stab at what the problem might be????
    
    JD

    Is your friend absolutely sure that the builder didn't skimp on putting
    in insulation in the trouble spot? I've heard of one case where this
    happened.
    	If there is a wall socket on that wall, remove the cover and stick
    a long thing screw driver *around* the edge of the box to poke around
    for insulation. If possible try to shine a flashlight in there.

    Nope.  Because we did most of the work.  The builder just
    told us more or less what to do.  Thinking back, the 6" wall
    is only 5-1/2"thick and the insulation said 6-1/4".   But I
    dont think that 3/4" compression would be that critical???
    	 
     To put in my 2c worth I mentioned something about the hot air
     getting into the wall thur the ceiling seeing that it was
    built with a 12' wall and a firestop.  But I dont remember
    how we tied the wall and the 2nd floor together??
    
    JD

    
    
      I have the following problem that needs IMMEDIATE attention.
    
    Yesterday afternoon my wife noticed a water stain in our living room.
    We have a split-level (raised ranch) home.  During the construction I
    speced. in a continious ridge vent.  This stain is directly in the
    center of the house about 4" in from the end where there is a soffet.
    
    Now, one of the problems is a I have a very bad back problem and the
    opening into the attic is very small.  I did inspect the roof and there
    are NO shingles missing.  I am assuming that because of all the snow
    and winds recently that snow has come into the ridge vent and soffet
    and settled in the attic.  With the heat on and the weather warming
    I again assume that this snow accumulation is melting.
    
    Question:  What can be done to stop the snow/rain coming into the
               ridge vent?
    
    Question:  What can I do to immediatley stop the leaking? and thus
               preventing the water damage.....
    
               Is this a case where I can file an insurance claim?
    
    I may be able to get into the attic and inspect this problem, however;
    it's getting out of the tight space I'm worried about with the back
    problem.
    
    Any and all information/tips would be helpful.
    
    Thanks!
    
    Bob Montville
    DTN:234-4974
    FLYSQD::Montville

I had the same problem after the Great Blizzard of '93.  I noticed a wet 
spot and got in the attic.  There were three plies of snow which I cleaned 
up.  One from each gable vent and one from another vent through the roof 
(not a ridge vent but I don't know whatyacallum).  The only problem was a
third gable vent to which I had no access.  So I have a wet spot.

Stan

    Use "bins" primer over the wet spot...repaint the ceiling.
    
    Marc H.

    You and I have the same only different problem. "BUT".. I have a 
    cathedral ceiling over my living/dining/kitchen area.  the
    other nite (monday) I got home and there were water stain spots
    over the front part and rear parts of the cathedral ceiling.
    My problem is that I can't get into the area where its wet as
    it's cathedral so no space.  This am when I check the ceiling
    there are MORE spots running towards the soffit.  Anyone have
    any suggestions.  do I leave it, and wait till warmer weather.
    don't know what to do as I can't get at the area between the roof
    and the ceiling.  How much water damage should I expect?  Will it
    dry out???? Please any input would be appreciated.  Any comments
    on insurance????  

    Leave it until the spring. Check the roof/soffits for any damage. If
    not..then repaint and chauk it up to an unusual event.
    
    Marc H.

    
    
    I should further state that I am a little concerned for the snow/water
    to affect the wireing.  The big problem with it running to the walls
    would be the down-drain effect and this shorting-out or igniting the
    electrical circuits.  Being a firefighter this really bothers me...
    
    
    bob

    
      I cannot imagine a situation where wet wires will cause a fire. In
    the last two houses I owned, water ran right into the breaker box from
    the main, there was never eny problem other than rusted screws on the
    breakers. I also have extension cords out in the rain/snow on a regular
    basis and there has never been any problem. As an electrical engineer,
    I can tell you that at 120 volts, water does not conduct well enough to
    cause problems in normal wiring. Heck, I even had water dripping out of
    a light socket this past week. It had run down the wire in the attic.
    If water on wiring was a problem, we couldn't put out Xmas lights.
    
      As a note to all these water problems. Due to the heavy snow and
    continued below freezing weather this past month or so, there is a much
    greater chance of having serioud ice dams on the roof. I bet most of
    these water problems are due to that.
    
    				Kenny

Just an aside (standard procedure for notes discussions) since we are
discussing water and insurance.  Now might be a good time to check your
flood insurance.  Here in NE there is a very large snow pack in the
mountains of NH.  If we get warm rains this spring, rivers (like the 
Merrimack) are going to be running through people's basements.

This may apply up and down the east coast of the US.

Forewarned is well insured,
Stan

    RE: .0
    	I have a continuous ridge vent and this morning I found wet stains
    in two bedrooms,right under the ridge line.I went into the attic,which
    is accessible from a little square hatch in a bedroom closet, and
    found several piles of snow directly under the ridge. With the
    ferocious horizontal winds we had ,snow just blew in througt the
    ridge vent.With the warming weather yesterday the snow started to melt.
    I removed several buckets of snow this morning,hopefully the stains
    won't grow.
    	My insurance policy says damage will only be covered if shingle or 
    other damage occured first,allowing snow or water in.
    
    Mike

    
      Amzing, but I suppose not so much so considering the high winds with
    the snow. I guess my gable vents aren't so bad after all.
    
      Point well taken about the flooding. If we get a heavy rain, MANY
    basements will be flooded, not counting the homes that'll get flooded
    from rivers. I remember 5 years ago when there was a lot of flooding
    around. Places that were pretty high still went under. There is so much
    water trapped in the snow now with this rain and with the ground so
    thoroughly frozen, a few inches of rain from one storm could do it.
    
    				Kenny

    Add me to the list, I also had snow in my attic under the ridge vent. 
    Fortunately, I got it out the night of the blizzard so I didn't get any
    stains.  (I went out into my garage during the blizzard, and saw this
    line of snow over the cars, etc.  That prompted me to look in the
    attic).

    At the high of the so-called blizzard, I watched snow travel *upward*
    maybe 20 feet from the edge of the roof all the way into the ridge
    vent.
    
    Residential construction techniques are defenseless against being
    struck by rain or snow moving upward (Unless you encapsulate your 
    house in rubber ).

As far as I can tell, no snow at all got into our ridge vents - we have
them on the house itself as well as the garage, and it would have been very
obvious had snow entered through the garage vent.  We've also peeked into
the attic and saw no evidence of snow.  I guess some ridge vents are better
than others.  (Ours has a "lip" on the outside which is said to deflect
air currents up; maybe this helped.  It also has a type of loose plastic
foam which is intended to keep bugs out.)

				Steve

    
  > It also has a type of loose plastic foam which is intended to keep 
    bugs out.
    
    Could be the effect of the foam too.  I had this every year in my first
    house until I stapled a thin layer of glass fiber insulation over the
    vent.  Didn't affect the airflow, but stopped the snow.  A furnace
    filter is good for gable vents.
    
    Colin
    
                                      

    GLORIA HUSTON
    DTN 223-9308
    POWDML::HUSTON
    
    
    With this last storm, I am experiencing snow melting on my roof and
    running down into the gutters and freezing up and overflowing the
    gutters and now I have icicles running down my house.
    
    Does anybody know how I can solve this problem?
    
    Someone suggested I might have a venting problem.
    
    
    
    

    I don't have an answer as to what you can do, but I can tell you that
    my whole neighborhood is like that. So, it's not just you . . .
    
    Marleen

    
      The better your attic insulation, the fewer/smaller your icicles. At
    the same time, you need good attic ventilation *above* the insulation.
    Most all houses will have some icicles. The question is whether yours
    are a sign of not enough insulation or a ventilation problem which its
    impossible to say without really looking in your attic.
    
    				Kenny

    Look at note 736
    

	    If the snow on your roof is melting faster than on all the other
	roofs in the neighborhood, it could indicate that you need more in-
	sulation in your attic.  

However.....a house with a very well insulated attic can still have icicles. 
Particularly on south facing slopes, the sun causes some of the snow to melt
down to the roof and run down the slope.  This causes icicles on extremely low
temperature days.  This also can cause an ice dam which can/will back up under
the shingles and dampen your attic.  

Two common remedies to ice dams are A) Aluminum sheathing along the eaves
extending 2'-3' up the roof  and B) Zig-zagging heating wire along the eaves
and, if you have them, along the inside of gutters and downspouts. The first
method HOPES to generate reflective heat from underneath the snow pack and a
slick(ish) surface to keep snow from adhering; both to keep snow from piling up
along the eaves.  The 2nd method accepts that nature may cause an ice dam no
matter how creative the homeowner, but relieves the dam by providing melted
channels for the under_snow melt to funnel down off the roof.  And, if you have
run a wire inside your gutters and downspouts, the melt may be channeled
wherever you like.  

The heating wire method is generally accepted as the "best" method for at least
two reasons.  First, no matter how much snow builds up, as long as you have
electricity, you will provide a runoff for the melt.  Second, the wires are
virtually invisible from the street; many folks do not like shiny aluminum edges
to their roofs.  However, this method will produce icicles if you do not have
gutters.

My neighbors have sheathing, many of them have had ice dam problems.  I have
wires, no ice dam problems, but IMPRESSIVE icicles at the drip-down points (I do
not have gutters).

As Always, FOr What It's Worth...

Dave

    Hi,
    
    I have a similar problem which seems to present itself as ice forming
    from the edge of my roof overhange running down the sides of my house 
    and onto the windows below.  Upon closer examination, I noted that even in
    last night's extreme cold, there was water dripping from the overhange.
    
    To me, this seems to be a problem of trapped warm air forming
    condensation, finding its way to the outside through openings in the vapor 
    barriers.  This concerns me from two fronts, the first being the loss of 
    heat, the second being the potential damage to the inner wall structure.
    
    If anyone has a good/direct approach towards resolving this I like to
    hear from them.
    
    Scott

    
      Scott - I'd be highly surprised if you could EVER generate enough
    condensation for that kind of dripping. The snow about the roof
    provides lots of great water supply. For you to lose that much moisture
    from your house (Even if you HAd that much which I contend that you do
    not) you would have to have a BIG air leak which would still melt the
    snow on your roof and cause what you're getting. 
    
    				Kenny

    Last night I discovered a pool of water in my bedroom in front of the
    bay window which is comprised of 2 double hung windows side by side.

    Water was pouring from the top of the window trim along the whole
    length of the windows.  There is water damage to all the wood (windows,
    trim, hardwood floors), it seeped thru the floor and ruined all sorts
    of books I had on a shelf in the basement below.

    Apparently the water was coming in because the gutters were ice dammed.
    The melting water could not drain properly and ended up working its way
    into our bay window.  This is in the front of our house.

    After cleaning up the mess and placing buckets in the window sill to
    catch the continuing flow it finally stopped.  At 2:30 this morning we
    woke up to the noise of dripping water in our dining room.  The same
    thing had happened at one of two side by side double hung windows
    located at the back of the house.  These are not bay windows but flush
    to the house.

    Cause was again ice damming at the back gutter.

    We have notified our insurance company and an adjuster will be out in a
    week or so.  We were advised to try and break the dam in the gutters by
    chopping holes in the ice every 5 feet or so.  Someone else suggested
    sprinkling road salt (this would be much easier to do) along the length
    of these gutters. 

    I am looking for suggestions on how to stop this now and from ever
    happening again.  Of course this problem only occurs during melting
    temperatures.  The gutters this morning contain about half the amount of
    ice that was in them last night due to the warm temperatures over night.

    Once all the ice is gone, so is the problem, until next time...

    Thanks, Mark

A common solution is a heating cable.

Stuart

    I would add.......use the 3 foot membrane ice/snow guard under the
    shingles,starting at the drip edge and going up about three feet.
    
    
    Marc H.

See note 736.

Before I installed heater cables, I had a monstrous ice dam on the north side 
of the house.  I was nervous about using hatchets, pic axes, plastique, etc.  
So, I ran a garden hose from the drian of my water heater and "carved" channels 
with hot water.  a tad messy, but effective and I did not risk chipping 
shingles.

Dave

           Yep, I've got dams.  Min damage thus far.  Anyone know who in
           So. NH might have roof rakes?  
           
           Steenbeke & Sons in Salem is all out ($35/ea), but they rent
           'em for $10.
           
           Steve

You can mail-order them from Northern Hydraulics.

If you use an aluminum roof rake, as I do, you might consider the following
modification tip for which "The Family Handyman" sent me $100 (and a nice
Stanley handsaw) when they published it in the October 1993 issue:  Buy
a vinyl door sweep (I actually used one which was aluminum with a vinyl sweep)
and attach it to the leading edge of the rake so that the vinyl sweep extends
about 1/4 inch past the metal rake edge.  This will not degrade the rake's
action, but will be kinder on your shingles.  (Note - when TFH published it,
they pictured the sweep attached to the trailing edge, not the way I had it.
I don't recommend this.)

				Steve

    	Simple solution: just remove the gutters. :-)

    	Seems gutters are more times a pain than a help. Between ice dams
    	and having to clean them out constantly, I can't see the advantage
    	of having all the roof water go to one place being worth it.

    	I don't have gutters on my current house. Are there any reasons I
    	should? As I said they seem to cause more problems than they
    	help... 

    	-Erik

    RE: .5
    
    My old house didn't have gutters when it was first built about 1830.
    Because of the water that splashed back onto the house, the sill in
    many places rotted out and had to be replaced. Also, much damage was
    done to the bottom "water board" and lower siding.
    
    I have gutters all around my home now.
    
    Hey......its your place , do what you want...me? I have gutters.
    
    Marc H.

Even without gutters you can have ice dams.  I don't have gutters on the
front of my house and do get ice dams (less so where I improved insulation
and ventilation into the attic; it needs still more ventilation.)  Gutters
in the rear of my house have effectively ended basement flooding I was getting
during heavy rains.

				Steve

    
    	I have a French drainage system around the house, the ground slopes
    	away from the house and is covered with gravel on the roof rainfall 
    	line. I get very little if any backsplash and my sills are in
    	perfect condition (albiet the house is only 25 yrs old). I don't
    	have any problems with basement flooding. So is there any reason 
    	I still need gutters? Sounds like I don't, but there may be other 
    	reasons for installing them?
    
    	Also, do long roof eaves that hang out over the house sides for 2
    	or more feet exposed to the air on both sides help the situation 
    	any? I see some ice on the ends but it's on the eave overhang only
    	from what I can see...
    
    	-Erik

The ice dam may only be on the eaves, but the water that backs
up behind the dam may extend above the eaves.

I think gutters are only necessary if you are experiencing
problems related to runoff, i.e seepage, foundation cracks,
rot from splashback, etc...  Otherwise, it is only good for keeping 
water off your head when entering the house.

The snow rake has not eliminated my ice dam problem.  In fact,
it seems to have had little effect, except instead of the ice
being under the snow, it is readily visible.

Even with snow off of the bottom three feet of roof, the snow
from above the roof still melts, then freezes when it reaches
the eaves.  I'm starting to wonder why the bother, unless to
rake ALL of the snow off of the roof after each snowstorm.  The
snow rake is not the tool for this job.

Comments?

Comments?

Insulate.  The effort will be worth the elimination of having to contend 
with ice dams.

   A friend of mine is a general contractor, and he has been taking on
   some of these projects lately - that is, clearing out ice dams.  His
   advise to me was as mentioned earlier - hook up a garden hose to the
   hot water line that feeds the washer.  He called this a mini laser and
   said that it was a lot easier and safer than ladders and chopping and
   stuff like that.
   
   His only piece of advise was to be careful - hooking up a hose to a
   hot-water-only feed will give you a very hot hose nozzle.
   
   FWIW,
   
   - Tom

Of course, what .84 meant to say was "Insulate and ventilate"

:-)

    Agway in Peterborough has roof rakes.  I imagine all of them do.
    Belletete's, one of Peterborough's hardware stores ahs the has them
    too.  (I think Agway want $35 for one).
    
    Ken

    
    If its thats bad and you have to get it off the roof.
    Get one of thoes 20lb LP tanks and a torch and melt it
    off.  Then install some heat tape.
    
    JD

    Question about the hot water to help with the ice dams...i really like
    this idea - but what I'm wonderig is would it work on a house like
    mine where the roof is like 2 1/2 stories high (gambrel) and the ice dams 
    are part way up that roof line?
    
    carol
     

   re: gambrels and other tall houses..
   
   Not sure, actually, since I don't have anything that tall..
   
   I'd speculate that you'd need some really good water pressure from the
   hot water tap, and that you'd risk losing a great deal of the heat by
   the time the water made it up to the affected areas...  may not be as
   effective for your place, but that doesn't automatically mean it won't
   help...
   
   Anybody have first hand experience with this?
   
   - Tom

    RE :.12
    
    Rule of thumb.......feet x2=PSI
    
    Marc H.

    
    I have a gambrel. With the right nozzle, I can shoot a stream over the
    house from back to front.
    
    The right nozzle is brass, with no control and a very small opening
    slightly wider than a pencil. It produces a very tight and forceful
    stream that should allow you to concentrate the hot water in the right
    place.
    

I acknowledge that insulating and ventilating would sove my problem.
But I have an "open" log home, cathedral ceilings throughout, and
two layers of decking that don't permit an insulating material to
be placed between them (unless I'm willing to rip off the new
roof shingles, decking, and sister a new roof on top of the old one 
adding ventilation at the same time.  I'm not willing to do that at this 
point.

I was mainly asking how the roof rake is supposed to "solve" the ice
dam problem.  It doesn't in my case.  It just makes the ice more visible.

It will solve it over time.  The dam forms when melting water is trapped by
the snow above.  With the snow covering removed, the sun will eventually
melt the dam.  Yes, you'll get some trickle from the snow above, but it won't
typically form a new dam.

				Steve

    
    That sounds like it would work!  And now - one more pesky question -
    do we know if the water will still be even halfway warm when it lands
    on the roof areas?  or will it contribute to the problem?
    
    i wish this would be the trick that works or at least gets us by for
    now.
    
    carol

Tape an open-ended hose to your roof rake.  Place the rake on the eaves, 
turn on the hot water.

for second story folks:

open second story window.  have companion raise above-mentioned roof rake 
up to your grasp.  raise said assembly to eaves.  turn on hot water.

    Well it is probably best to wait until the temp goes over the freezing
    point when you hit it with hot water.
    
    I'm not sure what I am going to do yet.  I have a cape with rear
    dormer.  I can hit the lower level gutter in the back from within
    a second floor window.  
    
    The front of the house I'll have to try to hit from the ground.
    
    Lets see shoot up/over/down into the gutter.  Sounds a bit tricky.
    
    Had the insurance examiner out this morning.  He said he would place
    a claim for refinishing the hardwood floors, the window wood trim,
    and a ceiling re-painted.  Personel contents were not covered, these
    included books/manuals, drapes, etc that were water soaked/stained.
    
    However if a pipe had broken personel contents would have been covered.
    Roof leaks are not listed as a peril to personel contents in our
    policy, but broken pipes are.
    
    In reviewing the policy it was reassuring to see that we were covered
    for volcanic ash damage/cleanup.  You see a lot of that risk in
    Massachusetts :-)
    
    I ultimately plan to install those heat wires to prevent this from
    happening again.
    
    Thanks, Mark

�    That sounds like it would work!  And now - one more pesky question -
�    do we know if the water will still be even halfway warm when it lands
�    on the roof areas?  or will it contribute to the problem?
    
    As long as the stream of water doesn't freeze on the way up, it will
    still be warmer than the ice you are trying to melt.  If this wasn't
    true, the ice cubes in your cold drink would never melt.
    
    There is also a plastic version of that high pressure nozzle.

>  With the snow covering removed, the sun will eventually
>melt the dam.

Eventually, yes (hopefully before April).  But the temps here in 
GMA have been close to 0�F for about a week.  Not a bit of melting.

>  Yes, you'll get some trickle from the snow above, but it won't
> typically form a new dam.

Maybe my situation is atypical, but it has.  It seems obvious that 
with cold temps and a mild roof, dams will occur whether you rake
or not. 

PS When the melting does begin, it will take a while to melt the
dam, less time to melt the snow above, thus causing the water-
damage potential.

    My home is in Nashua, NH.  It was -5 when I got up this morning;
    highs have been around 12.  Nevertheless, the ice dams on my roof
    are melting, and a considerable portion of the roof shingles are now
    exposed.  The sun works well, even if the air is cold.  Of course,
    it helps to have a southern roof exposure.
    
    			Steve

    RE: .18
    >true, the ice cubes in your cold drink would never melt.
    
    :-)  - that's what I need - practical demonstrations!  thanks everyone
    for your help.   This weekend is supposed to be about 20 degrees warmer
    then temps we had during the week so I think we'll try some of this
    stuff. 
    carol

>    As long as the stream of water doesn't freeze on the way up, it will
>    still be warmer than the ice you are trying to melt.  If this wasn't
>    true, the ice cubes in your cold drink would never melt.

	Ah, but if the ice is cold enough, and the water not warm enough,
	then the stream of water *could* just get frozen and contribute to
	the ice dam, instead of melting the dam as desired.

	After all, the ice on a morning like today will be ~-10 degrees. If
	the water is only around 35 degrees then at best it would take a lot
	of water to melt the ice.

	Roy

    What about if you rented a pressure washer and added a small amount of
    the polypropylene glycol to the tank that normally holds
    detergent?  Maybe even salt would work, although the last thing you
    want on the grass & flowerbeds is salt. 
    

re .21:

I assume you mean propylene glycol, and I don't think you'd want that on
your property either.

    re: snow rake
    
    The real key to using the snow rake is to go out right after a storm
    and remove the first 3-4 feet of snow from the edge of the roof
    BEFORE the ice dam gets created.  If you keep the edge of the roof
    clear the ice dam won't be created, and even if it does it will
    be much smaller and clear in color so the sun can work to clear
    it much easier than if it were snow up to the edge.  If the ice
    dam already exists, it'll help to remove the snow from on top of
    it, but it won't help nearly as much as if you got rid of it before
    the dam was created.
    
    andy
    

    
      I, too, am having problems ... reviewed the hot water/hose suggestion
      with my friendly neighbordhood contractor (who BTW has a wonderful
      recommendation from someone else in this file).  He cringed,
      wondering if it would like "adding fire to fire".
    
      He ended up spending 2.5 hours  knocking ice off my roof, 3' back
      from the edges.  Last weekend I upped the insultation in my attic and
      opened up its windows for ventilation.  It has stemmed my problem
      (temporarily at least!).  My feeling is that none of the short-term
      measures solves the problem in and of itself, but that by taking a
      number of tactics, each contributes in some small way.  
    
      I'll plan to make more permanent improvements in the spring.
    
      I do think, though, that every house is an individual situation....
    
      The insurance adjuster meets me this afternoon!
    
      Linda
    

>    The real key to using the snow rake is to go out right after a storm
>    and remove the first 3-4 feet of snow from the edge of the roof
>    BEFORE the ice dam gets created.

That is EXACTLY what I did.

>  If you keep the edge of the roof
>    clear the ice dam won't be created,

Well, it does.  Snow melts from above, reaches the cold part of the roof, and ice forms.


> and even if it does it will
>    be much smaller and clear in color so the sun can work to clear
>    it much easier than if it were snow up to the edge.

That presumes 

1. Roof faces south  (boths sides can't) or
2. Sun is not obscured by evergreens

Both of the above are not true in my case.


If anyone wants to buy a snow rake, let me know, it doesn't seem to help 
unless both conditions above are met.

Ideally, the soffet(sp) should be vented and a device to prevent the insulation 
from touching the bottom of the roof should be installed anywhere there is 
a chance for the insulation to block the flow of air from the soffet into 
the attic proper.

In some houses this need only be 10 to 12 inches long.  In other houses 
(those with half stories) the barrier is usually 4 feet or better.

With the soffet vented into the attic and the attic vented at either the 
ridge or at the gables, the under-roof temperature is fairly close to the 
outside temps and ice dams rarely occur.


If the insulation blocks the free flow of air near the eaves, ice dams will 
still occur.

It is possible to prevent ice dams w/o venting the soffet, but the barrier 
between the roof and the insulation is still recommended.

The new addition in my house has soffet vents.  The older (84 years) portion 
has no soffet vents.  I have 4 foot knee walls and the top of the walls 
were filled with blown-in insulation between the walls (ceiling) and the roof.
I vacuumed out the blown-in insulation and installed a barrier in the space 
then replaced the insulation between the barrier and the ceiling.  Although 
there's no circulation, the temps are sufficiently cool enough to prevent any 
ice dams.


	--\___________________/--

from the end the barriers look like this, BTW.

...and they go between the joists like this....

---------------------------------roof---------------------------------------------
||--\___________________/--||--\___________________/--||--\___________________/--||
||         insulation      ||         insulation      ||         insulation      ||
||                         ||                         ||                         ||
------------------------------------ceiling----------------------------------------

    What exactly is an Ice Dam???
    

    An ice dam is a buildup of ice along the edge of a roof, usually along
    the roof overhang (no heated space underneath). As heat escapes through
    the roof from the heated space further up the roof, it starts to melt
    the snow, and the resulting water moves downhill until it gets to the
    ice dam, at which point it pools behind the ice dam. Depending on the
    pitch of the roof and the amount of overhand, this pool of dammed water
    can find its way under the shingles and into your walls or living space.

    
    Ice dams seem to form in the snow at the edge of the roof. My theory:
    
    Water trickles down the roof until it gets to the edge, where it has
    to decide whether to drip or do something else. Capillary attraction in
    the snow at the edge of the roof holds a certain amount of this
    water, which then freezes the first chance it gets. This creates a
    small "dam" against the water that wants to trickle down the next time
    things warm up. Capillary attraction again holds a certain amount of
    water, which again freezes, raising the height of the dam, and so on.
    
    Eventually the dam get high enough to back up water under the roofing.
    The first sign of this is icicles forming anywhere but at the drip
    edge (like from the soffit or against the wall); danger is mounting
    when dirty icicles begin to appear.
    
    I had large ice dams last year, but consistent use of a snow rake has
    all but eliminated them this year. The interesting part is that,
    contrary to the instructions which say to clear at least 4' back, I can
    only clear a foot or so back in some spots because of the height of the
    roof, but the dams are just as effictively controlled in those areas.
    

    
    Re .21
    
    Yes, I mean propylene glycol.  So why wouldn't I want to use it in
    this method? 
    

    Re: .29
    
    It is a hazardous waste for automotive shops to get rid of, for one.
    In addition, the idea is to mix it with water, and then you have an
    antifreeze mixture. It doesn't mix with *ice* very well.
    
    Marc H.

    I have a tall two story house with ice dams and leaks.
    
    I like the hot water approach, but I think a ladder is still the best
    way to get up and into proper range.   At least I won't have to be
    swinging anything at the roof, just stand there and direct.
    
    There is no way to see the roof from a second story window, or get an
    effective angle.
    
    	Dave.  (I'm thinking about this weekend for a counter-attack too.)

    
    .29
                  
    You're either thinking about ethylene glycol, or propylene glycol that
    has been used as an automotive antifreeze. In the latter case, it is
    only classified as a hazardous waste AFTER use because of the heavy
    metal content.
    
    Propylene glycol is used as a food additive and as a humectant in
    cosmetics like lipstick.  It's recently been EPA approved as a safe
    replacement for spray de-icers.  Although it still tastes sweet to dogs
    & cats, it's not toxic.   
    
    PG breaks down in a few days (as does EG, but without the intermediate
    risk of poisoning).  In the US it's frequently used as a volume de-icer
    for planes.  Having used it a lot on cars, I know that it works fast
    and prevents refreezing.  Is illegal for people to use PG in this
    way in the US?
    
     Colin
    

    I have soffit vents and ridge vent on my attached family room, but the
    reason I get ice dams is because I have a roof window that melts the
    snow and makes water run down to the edge, where the gutter helps
    create a beautiful ice dam. Last check, it was about 12" tall from the
    top of the gutter. :^( I have plastmo gutters, which are removable.
    I'll be exercising that ability as soon as I can get the ice melted
    from the gutter. A few years ago, I also added the flashing panels that
    replace the last 28" or so of shingles at the drip edge. That's
    probably the only reason there's no water inside the ceiling yet.
    
    Mike

re .32:

What are the breakdown products?  What do they do to plants?  For that matter,
what will propylene glycol to if it falls on plants before it breaks down?

    
    -1
    
    Apparently, safe enough to allow it to go into run-off and sewage    
    systems.  The stuff is sold by the drumful in marine catalogs for
    winterizing freshwater systems in boats.
    
    However, I was wrong in saying that it's use as a de-icer
    has been approved in the US - it's still under consideration by the
    EPA.
     
    Interestingly, unlike methyl alcohol which *is* used as a windshield deicer,
    it's not listed as a hazardous pollutant either.  New paints are being
    formulated to use PG in place of some existing paint base chemicals.
    
    I guess it's either not particularly efficacious, or just too expensive
    to be applied economically.  I did come across other references to
    using calcium chloride as a melting agent on flat or low-pitch roofs.
    That's not supposed to do any damage to plants.   
    
    

re: .34

>    I guess it's either not particularly efficacious, or just too expensive
>    to be applied economically.  I did come across other references to
>    using calcium chloride as a melting agent on flat or low-pitch roofs.
>    That's not supposed to do any damage to plants.   
   
   I'm a little surprised... I don't remember great volumes of info from
   my chemistry classes, but isn't calcium chloride just another salt?
   Yes, its not sodium based, but I guess I didn't expect it to be that
   much better.  Personally, without seeing more data, I'd still be
   cautious with it - not sure I'd want to be drinking it in my water..
   
   fwiw,
   
   - Tom

    I recently had an addition put on the front of my house and at that
    time I had the roofer put 3 foot membrane ice/snow guard under the
    shingles in the valley between the new roof and the old. Well I have a
    leak on one side at that point. My question is the roofer did not strip
    the roof back he just cut it along the new roof. I can't see how he
    could have gotten the membrane 1 � feet under the the existing roof?
    doesn't this defeat the purpose of using the membrane? The roofer is
    coming out todat to look at it any suggestions as to what I should
    tell him? Should I have him re-do it? 
    
    Thanks
    Tom Casey

	re: calcium chloride

	When I was buying some ice-melter, I was given three choices by my
	local hardware store:

	Rock Salt: cheapest

	Calcium Chloride & Potassium Chloride: one of these was billed as
	better for the environment, the other as working better in very cold
	conditions.

	I went with "cheapest"...

	Roy

    
    
    What you should tell him......"fix it right this time"...
    
    If you pop a few shingles, you'll be able to tell for sure...
    
    

    
    
    I'd like to know who started all this.   Needless to say
    I was up on the roof last night to prevent something 
    from becoming  a major problem......
    
    iceman

    
   > my chemistry classes, but isn't calcium chloride just another salt?
    
    Your memory serves you well.  As the later note says, it has some
    slight environmental benefits and is a tad more friendly to concrete.
    Most water contains it, many natural springs have a lot of it.  Plants
    can tolerate it better than sodium chloride.
    

 Sunday morning I woke up expecting to have a day of fun.  Then I looked up and
 saw icicles hanging down from the roof rafters _underneath_ the overhang.  I
 had ice dams, and spent the whole day dealing with it.

 I tried using the aluminum ladder to reach the roof with a shovel but it was
 6" too short and I didn't feel like taking chances piling up a base for it.
 The ladder had to rest above the 3ft overhang because being underneath it I
 could do nothing. 

 So that left me with spending my day with a shovel, on the roof.  I put on my
 trusty shiny-neon moon-walking-boots-from-hell that my friends and family love
 to make fun of until they wear them in the snow.  They have better, bigger and
 deeper treads than my car snow tires.  Otherwise I wouldn't suggest it.  I
 would suggest it period but I had no choice.  I shoveled the 6" of snow
 (seemed like 8" if that can be right) off the roof while trying not to lose my
 footing or balance.  Super leg work-out, but it was _not_ fun and took all
 day.

 Once the snow was gone (along with the corners of 3 shingles), I saw that we
 had 3-4" of solid ice from the edge to FOUR FEET up the roof! Instead of my
 3ft overhangs helping the situation, they made it worse.  So I tried the "hot
 water via garden hose" trick suggested in here.  There was a looser-packed
 layer of ice on top of 3-4" solid ice but I removed that with a shovel by
 breaking into sheets and chunks.  [Downside: the falling ice chucks damaged a
 few of my foundation plantings, I lost some rhoddie buds and that hurt a bit.]
 The clear ice was so solid that it was very quickly evident that no amount of
 picking (even with a metal spade) would ever remove it.  Picking the ice also
 makes you lose balance more easily.  I hooked up the hose to the 2nd floor
 bathroom sink faucet and brought it out the window.

 For about 15 minutes I had the "laser" noters here described.  Fifteen minutes
 allowed my to put a single 1/2"-wide run-off path all the way to the edge of
 the roof.  I tried to put one every four feet.  By the time I finished one
 side of the roof (6 paths), the hot water was ice cold.  I have an 80 gallon
 electric hot water tank (that's probably $50 right there).  It took forever to
 melt through that ice.  AND I WAS STANDING RIGHT THERE ON TOP OF IT! Able to
 direct a full strength stream onto a focused spot.  I can _not_ imagine this
 working by spraying water up to the roof while standing on the ground or
 through a window.  It was past dark by the time I finished, soaking wet from
 all the stream spray-back.

 This spring I'm installing the roof edge heating cables without a moment's
 hesitation! This was much too dangerous, much too time-consuming, and too much
 back-breaking work.  You have no idea how large your roof is until you have to
 shovel it.  :-) The super-hero boots help but not much.  I lost my footing
 several times (each time trying to aim the falling ice chucks away from my
 rhoddies).  The only saving grace is that the roof ice surface was granular
 and not too slick per se.  

 The drawbacks with using the "hot water laser" are:

 1) You have to be right on top of the ice with a very strong focused stream
    of water.
 2) It takes a lot of hot water to melt a very tiny path of ice.
 3) A spray (vs.  stream) of hot water just freezes up as it hits the ice, and
    and the slow pools of water that form behind the dam ice up too.  It also
    makes the roof more slippery.
 4) When you're finally done and come in soaked-to-the-bone and shivering cold, 
    there's no hot water to take a shower with!

 What a dreadful experience that was! The heating coils are going on the roof
 first thing this spring...

 -Erik

    It *does* take a lot of energy to melt ice...phase change and latent
    heat and all that.  
    It's also very difficult to chip ice off something you don't want
    to destroy in the process (like a roof).  I recall belaboring the
    ice on a roof with a hatchet, years ago, with little visible results
    regarding the overall mass of ice but with an ever-present danger of 
    ruining the shingles.  
    
    Hope for some 45 degree days....

    Damn (or should that be dam?), I'm glad I live in southern California!
    
    ;^)
    Jodi-

>          -< "hot H2O laser" was feeble against 4ft of 4" thick ice >-

	    I would have opted for fire, as in a propane torch.

					Tim

>    Damn (or should that be dam?), I'm glad I live in southern California!

	Why, how much hot water does it take to melt an earthquake? 8^)

	Roy

    
    :^)    I think I'd rather put up with a little ice damage than
           a lotta damage from quakes...
    
    Fred

    
      I installed the cables on one particularly troublesome part of my
    roof and it is EASY! The cables themselves are not that cheap, but the
    job of installing them is very easy. You don't have to leave them on
    even remotely all the time. Several hours every few days or when there
    is more ice or snow is quite sufficient to keep the channels through
    the ice clear for water runoff.
    
    				Kenny

    
    Well we've been using a roof rake and attaching pole saw extensions to
    it to increase the range for scraping off the snow.  We've removed
    quite a bit and there is also lots of ice left unfortunately.  We also
    discovered that an old bathroom fan (since disconnected) had been
    vented into the attic.  Even though we've never used that fan, the
    lack of insulation over that opening is sure to be a contributing
    factor.  
    
    so - forecast for more cold followed by cold rain and ice to come.
    
    carol

    
>	    I would have opted for fire, as in a propane torch.
    
    	I think a propane torch would have been a much better choice now
    	that you mention it. It would be much cheaper than electric hot 
    	water, much hotter, easier to carry around than a hose, you
    	wouldn't get wet, less slipping, and you'd even have hot water 
    	left to take a shower when you're done.
    
	How much are they usually? Does Spags sell them?
    
	-Erik

>    I installed the cables on one particularly troublesome part of my
>    roof and it is EASY! The cables themselves are not that cheap, but the
>    job of installing them is very easy. You don't have to leave them on
>    even remotely all the time. Several hours every few days or when there
>    is more ice or snow is quite sufficient to keep the channels through
>    the ice clear for water runoff.


    	I want to install the cables on my roof as well. How "not that
    	cheap" are they roughly?

	The other question I had is how do you attach the coils to the
    	shingles? I'd imagine using nails or staples would put holes in
    	your roof causing leaks when the snow melts. Do they use epoxy?

    	I would probably need the coils to make a S-loop along the edge of
    	the roof reaching up 4 feet high. Do you have to hang the coils all
    	the way off the roof before the bend (ie you'd see the bend hanging
    	one inch off the roof), so that the water has an ice-free clear
    	path to run all the way off?  

    	Are there any problems with them, say like leave piles or branches
    	getting caught up in them and ripping them down? 

        Who carries them, Home Depot or Spags? Can you get better deals if
    	you wait to buy them in the spring or summer?
    	
	They do seem worth it if I can avoid having to shovel my roof every
    	time it snows...

    	-Erik

                                

    Butler Lumber in Maynard has 60' length of cables for about $30.
    
    Bo

    Home Depot in Salem NH had 60 ft Frost King cables for $37.
    You attach them to the shingles using little clips that slide under the
    edges of the shingles and hook the wire.
    
    The box comes with all sorts of directions and help in assesing how
    much cable you will need.  You are urged to zig-zag the roof, and run
    a cable down the gutter and the downspout.  You cannot cut or splice
    the cable, but you can put out multiple "segments".
    
    Actually the kicker is that you are supposed to hook this all to an
    exterior GFCI protected outlet.  Extention cords and interior wiring is
    not warranteed.  As others have noted, having a pilot light on a switch
    is also reccomended.  Grounding any gutter system is also required.
    I think some of this is overkill and CYA on the vendor's part, but be
    very careful about the possible fire and electrical problems.
    
    	Dave.
    (PS: I am using a heavy gauge GFCI protected extention cord on a
    temporary basis and only when I am there and watching.)

	How much are they usually? Does Spags sell them?
    
	    I think less than $15.00 for a torch kit.
			
					Tim

    
    I've seen one in the Northern Hyd. flyer but cant
    seem to locate it again...  There not much....
    
    JD

    If you currently have an ice dam and don't have a heating cable
    installed, can you loosely drape the heating cable in a zig-zag
    pattern on TOP of the ice dam and then turn it on?  Will the ice
    melt??  Are there any dangers in doing this?
    					Thanks,  -Dave-

    
    Ah!, found it...    its a 50000btu propane torch.  
    its $39 +s/h.  I betya it will do a lot of hot dogs
    all at one time!!
    
    

    I called the roofer he came out and said that a couple pieces of
    flashing were wrong, he fixed them and said I should not have any more
    problems. As far as the ice dam goes he said that because the existing
    roof is almost a vertical (the front side of a very steep gambrel) he
    indicated that they normally just use flashing on this, he called it a
    manside?? he indicated that the membrane is used in valleys. is this
    true or is it just an excuse to not have to re-do some work??
    Thanks
    Tom

    re.108
    
      I would think that it would melt the ice just fine if you layed the
    cable on top. As long as there is physical contact. The problem you may
    run into is how to fasten the cable to the roof while this is
    happening? I suppose you could figure out the right size zig zag and
    just attach at the top assuming the top area was clear of ice. I don't
    see any reason why it would be dangerous (Except for working on an icy
    roof).
    
    				Kenny

    
    "Mansard" 

> ... flashing were wrong, he fixed them and said I should not have any more
> problems.

	My roofer has told me that twice so far (ie. that I shuldn't
	have any more problems) yet I still have the leak.

    
.2>    he called it a manside??
    
    Probably a "Mansard".
    
    A Mansard roof style has "two slopes on all sides with the lower slope
    steeper than the upper one" (from Webster's). While Mansard and Gambrel
    sort of share this configuration on front and back, a Mansard roof
    continues the same roof line on all for sides.
    
    

    The way I'd probably try this (putting wire on top of ice dam) would be
    along the following lines:

    1.	Don't try to match the final "installed" configuration.
    2.	Clear enough snow in a patch above the ice dam to reach the
	shingles, and attach one of the clips. If you can't get to the
	shingles to attach the clips, use a brick or something to weight the
	high end of the wire to the roof. (Or tie a string around the wire
	and wrap it around a vent pipe. Something to keep the wire from
	sliding off.)
    3.	Do #2 in enough places to get a rough zigzag of wire over ice dam
	(probably fewer zigs than a "real" installation if you're forced to
	attach the wire higher up the  roof).
    4.	*Weight* the low point of each zig so that as the ice melts the wire
	will be drawn down through the ice. Not a heavy enough weight to
	dislodge the whole wire, but enough to hold its zigzag pattern.
	Something the weight of a good-sized fountain pen would probably do,
	like a small stack of washers tied to the wire with string.

    I know *I* can picture the above, but I don't know if you can...

                                       ***        **
                      **     ***       / \        /\
                      /\     / \      /   \      /  \          A
    wire zigzag ->   /  \   /   \    /     \    /    \          r
    ice dam ->   ~~~/~~~~\~/~~~~~\~~/~~~~~~~\~~/~~~~~~\~~~~      r
    roof lip ->  =========v=======vv=========vv===================r
                          *        *          *                    g
                                                                    h!
								    
    The "***" shows a brick or clip attachment of the wire to the roof,
    the "*" at the bottom shows the small weight or whatever keeping the
    lower part of the heating cable in contact with the ice.  The message on
    the right is from the intrepid homeowner as he slides off the roof
    despite his best intentions.

    Good summary Paul.
    
    Yes, I have tried this and had mediocre success.  Mostly because the
    wire will just slide/spring all over the place, if you don't clip or attach
    it to something.  I finally did get it pressed into the snow and
    running it for a little while gave it some bite.  But you will have to
    be patient in positioning it.
    
    BTW: besides for shingle clips. In the kit, there are also some simple
    open clips for attaching the wire to other passes.  So, along the bottom
    of the zig-zags, you can hang the gutter wire.  This puts weight on the
    bottom of the zig and gives you something to attach the gutter wire to.
    
    (maybe I'll bring in the box and do some ascii art)
    
    	Dave.

    Well fortunately, this friday thaw and rain has washed away most of the
    roof accumulation.  (moving us prematurely into the
    spring:draining-the-yard project)   
    
    I ran my hap hazard heater wires most of the morning Friday and they
    managed to slice up the ice dam into many smaller pieces.  The rain &
    melt ran around the remaining chunks.  Now that they are down to mostly
    bare shingles, I think I should get up there and clip them.
    
    	Dave.

    .21 ff:
    
    To a certain degree, chemical fertilizers will lower the freezing point
    of water -- perhaps *judicious* addition of that would work (without
    harm).
    
    Dick

           Thank God for January thaws!
           
           Has anyone tried flashing (alluminum?) along the edge of roof?
           I'm told the ice will slide off it easier.  Will it also work
           on non-sun-exposure side of house?
           
           Steve (who's chopped ice, cleared snow, dropped "ice-melt" on
           roof with ladder that barely reaches edge of roof and who got
           hit in mouth with chunk of ice ;-)

    
    I don't know about actual flashing, but they do make aluminum
    panels for just this reason. Using them is a matter of personal
    taste (i.e. What is YOUR definition of ugly?)  ;-)
    
    	   Mac (who has a small cut on the bridge of his nose where
    	        a piece of ice shrapnel bounced off and a lump on his 
    	 	head from a chunk of ice that came FLYING off when 
    		coaxed with the snow rake.)  What fun!
    

    Well, this Saturday was surely a fun time for the ice dam crews of
    the world!  My spouse spent time on the roof shoveling and getting
    caught with a clear sliding path off the roof but made it to his
    ladder safely. (I couldn't hear him yelling for me while I was out
    back making sure the native birds were able to chomp down on fresh
    seed in ALL my feeders.)  He took my suggestion to then stand on
    the ladder and use the BFH to whack the devil out of the ice dam.
    Anyone need solid ice chunks for their punch bowls???  (one minor
    nit to this BFH method - do not, DO NOT aim at one's other hand!
    It cause one's finger that gets hit to swell!!!).  He spent Saturday
    night at the movies with a frozen green lime ice pack on his finger!


    justme....jacqui

    p.s.  The roof is clear now!

Well, I should of spent Saturday doing the ICE dam but I choose to work the
clearing the driveway first. But the time I finish chipping the driveway, it
was dark so I started on the Ice dam on Sunday.

With the help of a good neighbor to hold the ladder, I tried drilling the ice
with a cordless drill, hammering it, and hammer and wood chisel combo. Since it
was about 20� out in the shade, my neighbor got cold really quickly so I had to 
give hime drinks to warm up. But after doing about 16 ft section, my hands were
done for the day. 

Is there any other method to do this other then a chisel and hammer?

Dave 

    
    Well, the snow rake worked for me. I uncovered the dams on thursday
    night and about 4' back. The dams in the front of the house are
    completely gone (once the sun loosened them I was able to pull them 
    off with the snow rake). On the back of the house it took a 36' ladder
    and hammer/chisel. A floor chisel works better than trying something 
    like an old wood chisel. In the end, the best tool was the back end 
    of an old claw hammer. Just work your way back from the edge taking
    2-3" at a time. I never finished the back (the house is 70' long)...
    But even now the sun is taking its toll on the dams now the snow 
    cover has been raked off.
    
    								- Mac

    I don't like to brag....but...I haven't had a single problem with ice
    dams this year. My home (1830's) seems to be located with a good
    southern exposure on it. I removed a large evergreen that was blocking
    the winter sun....and haven't had one problem.
    In addition, I replaced all the old shingles and installed the bird 3
    foot ice and snow membrane at the roof edge.
    
    I have plenty of problems with the house, but, ice dams aren't one of
    them.
    
    Marc H.

    On Friday, my husband successfully broke a 6 foot section of the ice
    dam on the back of our house.  He used the "hot" water method mentioned
    in this file.  On Saturday, with the hot water and the sun was able to
    break the dam in the front of the house.
    
    Only 2 ceilings in our house won't need painting/repairing.
    
    Think SUMMER,
    Julie
    

    Inspired by a couple of the previous notes, I attacked the largest
    segment of the ice dam on the back roof of our house with my MAPP torch
    (which burns hotter than propane).  I was initially surprised by how
    *ineffective* the torch was against the 6" thick ice.  I spent 15 - 20
    minutes and managed to cut only a shallow channel about 12" long.

    Upon reflection I realized how ineffective the torch is on a copper
    pipe filled with water.  The water does a great job of distributing the
    heat so that the pipe doesn't get hot enough to melt the solder.  I'm
    guessing that the ice may have similar properties.

    Since the ice was melting all by itself and there were no visible signs
    of a leak, I gave up my experimenting.  I was also tired of the water
    dripping on my head -- I was leaning out the bathroom window that is
    conveniently located right above the best ice.

    -- Ward

    
    Mapp torch, a.....  Might be like trying to heat
    the house with a match. :)  The type of propane torch
    memtioned some way back had a little more ummpah to it.
    Like Baked roof ala'house!!:)
    
    JD

    It's a lot harder to heat ice than water.
    
    You can toss a small chunk of ice in the middle of a roaring hardwood
    fire and see a black cold spot for 15 or 20 seconds.  The same amount
    of water boils away immediately.  This phenomenon is easily explained
    by someone who understands it, but basically it has to do with the
    difficulty of changing from solid to a liquid.  
    

    Actually, it also takes a lot of heat to change water from a liquid
    to a gas.  Phase changes (solid to liquid, liquid to gas) take a
    lot of energy.  If memory serves (and it probably doesn't), one
    of the phase changes of water takes 144 BTU/lb, i.e. it takes
    1 BTU to change a pound of ice from 31- to 32-degree ice, and
    144 more BTU to change it from 32-degree ice to 32-degree water.
    (Or maybe the 144 is for water to steam, but you get the idea.)
    
    The phenomenon was described by a Scottish minister, Joseph Black,
    around 1790 or thereabouts, I think.  He used the term "latent heat".

a little off the subject, but...

I fraternity brother in college had a small refrigerator in his room where ice
and water could seemingly co-exist.  It would take days (like 3 or 4) for water
placed in there to freeze.  It must have been at just the right temperature that
it gained that energy very slowly.

-Al

    
    There's a classic physics experiment where, goven the right temperature
    and (low) pressure, water can coexist in all three phases (gas, liquid and
    solid) simultaneously.
    

    
    Another oddity is that even in a glass of liquid water at temperatures
    well above freezing,  tiny ice crystals form spontaneously and melt
    instantly.  

After the most recent snowstorm I used the roof rake to clear about 6-8 feet
of roof.  That portion is now bare and the ice dams have disappeared.
I do still have dams in the back where I can't reach them with the roof
rake, and I'm not willing to get up there with a ladder.  I've got 6 feet
of Ice and Water Shield on the back roof, 3 in the front, and haven't had
any problems with water seepage.

				Steve

Are brown icicles on the cedar siding a symptom of ice dams? 

I've been keeping a close eye on ceilings all winter and all is well.
But this morning I noticed that the back of the house has a lot of brown 
drip streaks and one area of them also has ice forming.  There are no 
icicles hanging from the roof edge -- just on the siding.  The soffit area 
looks normal and dry.

    RE: .130
    
    Brown=sawdust
    
    Marc H.

    re: .131
    Well, not necessarily.  I've found that color can leach out of wood
    sometimes.  
    
    But regarding .130 yes, I'd say you have (or had) ice dams.  Otherwise,
    I don't see any way for the water to get onto the side of the house
    like that to form icicles. 

Well, here's an interesting twist on ice dams.  Up until yesterday I was
cheerful because, even though I have ice dams on the back roof of
my full-dormered Cape, I also had 6 feet of "Ice and Water Shield" which
should protect my roof against any damage.  Yet yesterday morning I woke
up to find water seepage on ceilings and walls in the back of the house
(down to the first floor as well!)  A look into the attic doesn't show any
moisture, but a look around back shows that I have icicles (and water dripping)
out of my soffit vents and down the back of the house!!!  How did the ice
get into the soffitt?

I called my roofer and he explained that what sometimes happens is that ice
builds up in the gutter (there is a gutter on the back; necessary for
the rest of the year!) and pushes up the join between the fascia board and
the roof, causing water to enter the soffitt space!  There's not much I
can do about it except clear off as much as I can and wait for the ice
to melt.  Augh!

				Steve

Easy fix, get rid of the gutters! Gutters cause more harm than good in
New England.

    
    
    Not much discussion about the use of rock salt to get rid of the
      ice dams once they're there.  Any opinions?  Would it cause damage
      to the roof?
    
    thanks, Dennis

re: water in the soffets

>Easy fix, get rid of the gutters! Gutters cause more harm than good in
>New England.

	This (water in the soffets) just happened to me this morning, and I
	don't have gutters. We finally got ice dams after this weekend's
	weather, after having no problems earlier. So, getting rid of the
	gutters may not do the trick.

	Besides, there are cases in which gutters are necessary. You can't
	always set up drainage around a house the way you'd like, for
	various reasons. I agree that gutters should be a last resort in New
	England, but the assertion that they do more harm than good is about
	as valid as most blanket generalizations.

	Roy

    
    > Not much discussion about the use of rock salt to get rid of the
    >  ice dams once they're there.  Any opinions?  Would it cause damage
    >  to the roof?
    
    During the recent news spots about a collapsed roof in Mass, the fire
    chief suggested using a "melting agent".    Apart from damaging
    plantings around the house, a more serious problem is that salt run off
    corrodes nails and damages paintwork.  All the possible alternatives
    have some drawback.

RE: Rock salt

Heard a story of someone doing this, and what they ended up with was salt
water leaking in their house (ie much more of a stain problem!).

bjm

I need the gutters, otherwise I get a flooded basement.  I think it's the
new gutter guards that are doing it to me; they're the solid aluminum kind
that slip under the shingles and have a curved lip on the other side so that
water falls into the gutter.  Brookstone sells them.  I think what happened
is that ice built up behind the gutter guard and pushed against the soffit
rather than spilling over.  This is the first winter I've had these
gutter guards and the first I've had this problem.  Argh!

				Steve

>    <<< Note 736.136 by NOVA::SWONGER "DBS Software Quality Engineering" >>>
>                           -< I've joined the club >-

>	Besides, there are cases in which gutters are necessary. You can't
>	always set up drainage around a house the way you'd like, for
>	various reasons. I agree that gutters should be a last resort in New
>	England, but the assertion that they do more harm than good is about
>	as valid as most blanket generalizations.
>
>	Roy
Gutters are sort of a band-aid approach to solving a wet basement. Perimeter
drainage or proper soil pitching might solve the problem without resorting
to gutters.
Most people that I've spoken with, (with ice dam problems), have gutters.

Ross

> This is the first winter I've had these
> gutter guards and the first I've had this problem.  Argh!

	Could be just a coincidence.  My folks have never had problems
	for 20 years (and they had gutters installed 10-15 years ago),
	until this year that is!

Re: .140

I agree that, if possible, proper soil grading and perimiter drainage is
preferable, but it was not possible in the case of my house.  We had the
grading changed as much as we could without turning my first floor into
a "below ground" floor.  

Gutters are indeed a source of many problems, but they are sometimes
necessary.

				Steve

    part of my house has gutters and part does not. I have ice dams all
    over the house. The leaking is on the part without gutters this week.

    My soffits have also been full of ice for weeks (icicles dripping..)
    but the only leaks form them was when they dripped down the side of the
    house and water came in above the window frames. I went out and caulked
    the top of the windows. At least those leaks have not repeated.

    the gutters in bakc ARE new so anything is possible..sigh
    
    Barry
    

I suspect I'm going to have to go with gutters this year myself.  Grading is
not a problem as the water I'm concerned about is dripping down
the side of the house in the back, and soaking the wood that is above the 
foundation, and the foundation goes about 1 1/2 feet above the ground
level.  Part of the problem is the deck, which I flashed this past
summer, and seemed to greatly improve the situation, but during very heavy
long storms, it still got a bit damp under there.  And I totally forgot
(or just plain ignored) the deck we have out the bedroom, which I now noticed
also seems to cause the same problem in the garage.  If I can flash that
and put up gutters, I think I'll solve 90 percent of the problem, and 
make the house less appealing to carpenter ants.  Then I think I'll spring
for the heating cables.  This past weekend I got out the ladder and tried 
a rake to pull down some snow (just a rake, no snow rake).  After a while
I took a crow bar to the ice.  After breaking a small channel, it was
relatively easy to pry loose 1 to 2 foot sections at a time, which fell 
into the snow below with a satisfying whoomphf!  Have to be careful with
this method though.  Don't want a large chunck of ice to fall onto you
when you're about 10 feet off the ground with one hand and snow/ice
covered boot bottoms your only support on a metal ladder.  Kind of 
fun though.  Couldn't do the whole roof, as the section over the 
garage would require about another five feet in ladder length due
to the driveway being below the level of the front yard at that point.
When's the next big snowstorm??

PeterT

>Most people that I've spoken with, (with ice dam problems), have gutters.

	As I said, I don't have gutters and just got ice dams. We have
	plenty of insulation (as the 1.5' of snow on our roof will attest),
	and didn't suffer from the problems last year or until this morning.

	Also, many of the houses in my neighborhood (also gutter-less) have
	had to have their roofs shovelled or ice dams cleared. It was simply
	a nasty year for ice dams.

	Roy

It is not surprising that many folks in the S. N.H. area are noting that this 
is the first year they have had problems.  We have been in this house since 
1971 and have seen two or three cycles of weather in that time.  The last 8 or 
so years have been very mild with little accumulated snow on the roofs.  I 
remember winters when the snow cover on the roof (5-12 pitch) was higher than 
the vent stack and actually had some melting down the chimney.  The last few 
years we have had not much more than a dusting accumulated.

Shortly after we moved in we got hit with a bad winter and ice dams.  That was 
the year (next summer) when the heating wires went up and gutters came down
(just could not afford to run the wires the length of the gutters and down the
downspouts). 

Y'all have my sincere sympathy.

Dave

	    There is an alternative to gutters that I considered installing.
	Instead of gutters to channel the water, you install a deflector
	array to make the water sprinkle away from the house.  They looked
	easy to install and the concept seems sound.  Has anybody tried
	these?
	    I'll try to draw a picture:


					      _-
				          _-
				      _- roof
				   -____________
				       |	|
		Deflector array	       |	|
			\	       |	|
		  	      / / / / /		|
						|

	    Water dripping off the edge of the roof hits the deflector
	which projects the water away from the house.  And NO downspouts
	to deal with!
	    BTW, I have gutters but no ice dams.

					Tim

    
    Seems like  a good thing for the rain Tim.  but what happens
    when the water freezes on the deflectors?  Although I would think
    it would pose less of a problem seeing the water isnt confined to
    a limited area.
    
    I'll attest to the fact that this is a bad year for Ice Dams.
    But it seems that taking the first 3or 4' of snow off my 3-12 pitch
    roof hads taken care of anymore major ice backups.  So much for
    this years headaches!
    
    JD  

    
    Tim,
    
    Are these the "rainhandler" gutters advertised in various home
    improvement mags?  I hae the same reservations as .148, that they
    would handle ice no better than gutters.
    
    On the other hand, if they were hinged so you could drop them down in
    the late fall....
    
    Colin
    

re .147:

Slatted gutters are discussed in 3930.

I've got the "Rainhandlers" on the front of the house, where the only issue
is keeping the water from digging a trench just outside the foundation.
They work pretty well for that, but are no good if you need to REMOVE water
from the area.

As for ice; yes, icicles do form on them, but they don't build up ice like
gutters do and don't contribute to ice dams on the roof.

					Steve

    It sounds like then no matter what you do, you can still have ice-dams!
    
    Gutters/no gutters	insulation/no insulation ventilation/no ventilation
    heated cables/no heated cables.
    
    What's a boy to do?
    
    I only say this because I have soffit vents, ridge vents, insulation,
    though no heated cables.  I was thinking of getting gable venting and
    a fan but now I don't know if it'll be worth the cost!  Plus I don't
    know how the fan would know when to turn on anyway!  Maybe I'll just
    get more plastic pails...
    
    -TB

>    What's a boy to do?

Clean living's the answer.  Either that or move to the tropics.

	> but what happens when the water freezes on the deflectors? 

	The Rainhandlers hang below the eave, so they couldn't contribute
	to ice dams (even if they did ice up).

>    Are these the "rainhandler" gutters advertised in various home
>    improvement mags? 

	No idea.  I saw them at HQ.

> They work pretty well for that, but are no good if you need to REMOVE water
 from the area.

	For most landscapes, I would think you just need to keep the rain
	water away from the foundation.

>    It sounds like then no matter what you do, you can still have ice-dams!
 
	I've been looking around since this note has been reactivated.  There
	doesn't seem to be a pattern as to which houses do or don't have ice 
	dams.  It's probably a combination of things that cause them.

					Tim

re>     <<< Note 736.152 by WONDER::BENTO "I've got TV but I want T-Rex..." >>>
>                           -< All is lost then???? >-
>
>    It sounds like then no matter what you do, you can still have ice-dams!

Well,  there IS a 100% solution to the ice dam problem.  The house I spent most 
of my childhood in never had an ice dam problem; yes, still in NE.  This place 
was built in the 1800's, sometime. There were no eave overhangs and there was 
no insulation in the attic (or anywhere else, for that matter).  Heating was 
"gravity" and we kept a coal fire banked all the time.  So, 100% of the roof
was heated 100% of the time. All melt kept melting.

Is this practical today?  Perhaps.  Assuming you have no eave overhang or if 
you do, there is an air gap in the overhangs between the insulation and the 
underside of the roof, the key is to make sure you never have any snow 
on the roof to melt down and form an ice dam.  I guess if you wanted to, you 
could heat the attic during/after each storm to assure a clean roof.  Once it 
is all melted, close the attic off again.  Snowy seasons could be expensive, 
dry seasons, not so. 

Dave

    
    I'll bet A-frames or houses with steep roof pitches don't have an ice
    dam problem.
    
    Phil

    Well, it's my turn...I was up on the roof yesterday for the second time
    this year breaking the dams.  It's an older house (+/- 1920), with a
    12/12 pitch, and the insulation is hurting (at best).  I plan to
    insulate better this spring, as well as soffits.  It's a new roof,
    with a ridge vent and gable end vents.  
    
    After breaking through the dams, chunks of ice were stuck to the
    shingles and some pieces of the shingles went south with the ice. 
    Since that appears to be a problem, as well as the fact that I'm
    terrified of heights, I do plan on either flashing or heat cables.
    
    I imagine the cables are easier, but probably a little more expensive.
    With how I feel about heights, I'd rather spend as little time as
    possible up there.  Am I correct that the cables are easier than
    flashing?  Cost-wise, what would flashing run me?  The house is 
    about 40 - 45' long, with a minor dormer, so I'd be looking at 100'
    of flashing or so.   
    

>     I'll bet A-frames or houses with steep roof pitches don't have an ice
>     dam problem.

	I have an old house with a steep pick and that roof never
	has any ice dams (just icicles haning from the flashing).
	My other roof (L-shaped house) had some small ice dams, but
	no known leakage.

	My folks however who I mentioned are getting lots of them
	this year but haven't had them for 15-20 years, have a grambrel
	where one side of the roof is super-steep.  That's the side
	they are getting the water coming in from, mostly due to ice
	dams forming in the rain gutter.

    
    There's always standing-seam metal roofing. You can still get an ice
    dam but there's no way for the water to get through the roof. One
    drawback is that when the ice dam finally slides off, it can kill
    anyone who happens to be underneath (this has happened a couple of
    times in northern NH in the past few years).
    
    JP

��       <<< Note 736.159 by SEND::PARODI "John H. Parodi DTN 381-1640" >>>

��    
��    There's always standing-seam metal roofing. You can still get an ice
��    dam but there's no way for the water to get through the roof. One
��    drawback is that when the ice dam finally slides off, it can kill
��    anyone who happens to be underneath (this has happened a couple of
��    times in northern NH in the past few years).

    Is this something that could be used on a house?  Or would it
    be too expensive, or to out-of-the-ordinary to be resale-able?
    Shingles seem to be such an antiquated idea.

    Beyond ice dams, a strong wind can blow off a few shingles
    and you get a leak.

    What 'high-tech' roofs are available for homes?

    Thanks.

    	- Lee

    Metal roofing along the roof eaves is a fairly common sight in New
    England to prevent leaks from ice dams. So, yes it can be used on a
    house (you expected them to be used on cars, maybe?). A similar solution
    is double-coverage roof rolls, which are also applied along the eaves
    and overlap each other (completely sealed) by 18" or so. We've got them
    along our eaves for six feet back (we've got 3' overhangs and a shallow
    pitch). We had ice dams leaks back around 1977 before installing these
    (that was when I learned what an "ice dam" was). Got nice large ice dams
    this year, but no leaking ... the water can just stand on the roof rolls
    with no place to go.

    The roof rolls have the slight advantage over metal roofing that ice
    doesn't "slip off them", so it's unlikely to kill anyone. Installation
    on an existing roof requires getting the existing shingles to lap over
    the rolls (this would also be true of metal).

I took a look at what was going on in back of my house and found a solid mass
of ice from the gutter up to the roof line.  I suspect the solid gutter guards
are contributing to the problem as they would tend to force ice up against
the soffit, but I only have them half-way across and there's no visible 
difference between the section with the guards and the section without.

				Steve

    I came home last night to find ice gathering along the cedar shakes
    on one side of my house.  It's right at the inside corner where
    our existing house meets the addition we put on 5 years ago.  Both
    the original house and the addition have the 3 foot ice-dam sealer
    under the shingles, along with adequate insulation and ventilation.
    However, we do have gutters (and no guards like Steve L appears to
    have).  I climbed up to the roof this morning and found that
    essentially normal melting got to the gutters, froze, and made
    a nice ice blockage.  As more melted, the ice grew.  With no place
    left to go outwards, the water built up along the facia between
    the gutters and the house, and worked their way under the flashing
    and under the plywood.  Fortunately, this 1 spot only dripped 
    under the eaves and not inside the house (probably due to leaking
    only at the facia and not under the shingles farther up).  But
    I chopped away the ice from the whole area, and kept the gutters full
    of ice, but low enough to let the water run off the roof  and over
    the gutters when it melted.  I thought about clearing the gutters but
    the frozen full along the whole house perimeter, so I figured for
    now I'd make the gutters get bypassed completely.  
    
    Should I get coils for the gutters for the winter?   Interesting
    idea, since I don't need them for the house itself, and just laying
    a strip inside the gutter is easy.  I will probably check into it
    during the summer when the rush for heating coils has dropped when
    the temps hit 90.  :-)
    
    andy
    

    
    >I'll bet A-frames or houses with steep roof pitches don't have an ice
    >dam problem.
    
     bzzzt! Guess again! ;-)
    
     I snow raked my neighbors nearly vertical front roof to help alleviate
     problems from foot thick ice dams this year. Face it folks, this is 
     just a BAD year for damming.
    
    							- Mac

    I'll add that even with "Ice barrier - membrane" - I still have roof
    leaks caused by ice dams - and I rake down the roof after it snows.
    
    Of course I have an interesting roof line that causes the problem. The
    roof line with with membrane applied is about 12 feet wide and sits 
    between two vertical walls.  What happens is when an ice dam forms it
    backs up the water high enough to leak into the vertical side walls.
    I only have the normal step flashing at these vertical side walls.
    I will be using heating cables from now own. 
    
    This roof line has four skylights and two bathrooms (two family duplex)
    and a cathedral ceiling with only 6 inches of fiberglass insulation and
    full vents at both ends (top and bottom).  I also do NOT have gutters
    at this location.  With the temps in single digits and lower it has
    been extremely hard to prevent the build up of an ice dam with the
    snow rake.
    
    /Howard

��                 <<< Note 736.161 by HYDRA::BECK "Paul Beck" >>>

��    Metal roofing along the roof eaves is a fairly common sight in New
��    England to prevent leaks from ice dams. So, yes it can be used on a
��    house (you expected them to be used on cars, maybe?). A similar solution
    No, I meant as opposed to sheds, barns and commercial
    structures, where I had seen metal roofs.

    My car has no problem with ice dams, just with damn ice.

    The metal being talked about here is just along the eaves (with normal
    shingles along the remainder of the roof) rather than full metal roofs.
    It creates a seamless barrier so that when water builds up behind an ice
    dam it can't back into the house.

    I don't think I'd want a whole roof made out of metal. Think of trying
    to get any peace while it's raining (or worse, hailing)...

    
    I've got a 12/12 pitch roof and 2 4/12s on each side of the steep
    one and have not had any problems with ice dams.  My problem, minor
    that it be, is the ridge vents.  I have a Lindal "JUSTUS" with the 
    R40 roofs.  Insulation is "THERMAX".  Whenever we get a fine snow
    driven almost horizontal by the wind, it gets in the ridge vents,
    settles on top of the thermax and whenever the sun commences to
    warm things up, we end up with drips thru the wood ceilings.
    
    In the last home we had, the roof ran east/west. The builder didn't
    have soffit vents, only two small peak vents.  When we had high
    winds out of the north during the first winter of burning wood,
    the roof actually acted like an airplane wing.  The wind would rush
    up the north side and actually pull a vacuum in the attic. With
    that, the higher pressure from the living space would make it's
    way to the attic and of course this left us at a lower pressure
    than ambient. What was the path of least resistance for the higher
    ambient to get into the living quarters?  The woodstove flue.
    Filled the house full of smoke 2 or 3 times that winter.
    
    Additional soffit vents cured that real quick like!
    
    Fred

    If you drive up to northern Maine (and probably northern New Hampshire
    and Vermont), you'll see metal-roofed houses all over the place.
    

    
    My mother-in-law has a metal roofed pre-fab garage about 12' away from
    the house. On the same side of the house she has a sunroom. A week or
    so ago ice began careening off of the metal garge roof with enough 
    speed to leap the divide and crash through into the sunroom.
    
    Just gotta love winter in New England.
    
    							- Mac

    ��<<< Note 736.167 by HYDRA::BECK "Paul Beck" >>>

��    The metal being talked about here is just along the eaves (with normal
��    shingles along the remainder of the roof) rather than full metal roofs.
��    It creates a seamless barrier so that when water builds up behind an ice
��    dam it can't back into the house.

    I have that.  It's commonly called ice belting.

    .159 mentions 'standing-seam metal roofing'  That's what I'm
    asking about.  I've seen contemporary commercial buildings
    with metal roofing -- it looks like it might be aluminum or
    enameled steel.

    	My house is painted white. It now has brownish streak running down
    most of the front of the house and a few brown icicles to boot..Very
    attractive, but at this point no leaks inside *that I can find*. My
    pull-down attic door is broken. So I can't get up there unless I want
    to re-fix it...but I'm afraid to pull it down anyway. My only hope is
    that all the wildlife living in the walls of my house are drowning.

    
    Lee,
    
    Questions about these roofs have come up before and my suggestion is to
    call a hardware store or roofing company in Conway or Laconia or Berlin
    (that's BURR-lin) NH. But note Paul Beck's point -- they're great for
    snow but any other precip is going to be noisy.
    
    There are some other interesting new roofing materials including
    concrete shingles and enameled steel shingles. I don't see why they'd
    be any better at handling ice dams, tho.
    
    JP
    

>    It sounds like then no matter what you do, you can still have ice-dams!
>    
>    Gutters/no gutters	insulation/no insulation ventilation/no ventilation
>    heated cables/no heated cables.
>    
>    What's a boy to do?


For 79 years my house never had gutters except on the now-removed porch, yet it 
has had ice dams every winter I have owned it (since 1978) until I built the 
addition and INSULATED/VENTED IT and INSTALLED GUTTERS.  

I never had any ice dam problems with the gutter on my porch.  They were 
always on the roof of the house.  The addition has gutters on both the 
east and west sides.  The west side is protected from all but the late 
afternoon sun by the main part of the house that runs at right angles to it
.  If anything were a candidate for ice dams, this arrangement is.

I don't have ice dams on the eaves.  I do get a heavy snow build-up in a 
valley on the north/northwest side of the house, but the runoff still flows 
under it.

Other than where one hanger has come loose and the gutter dips the wrong 
way, my gutters don't fill up with ice either.  This spring, I'll re-hang 
that section and get the pitch corrected so the water flows to the 
downspout instead of to the capped end.

    	I just read something recently about a new kind of roofing
    material. I don't remember where I saw it, but it looked interesting.
    It was made from recycled plastic and formed into 20"x40" interlocking
    sheets.
    
    	There was no price given, but they said it was a little more
    expensive than traditional materials. They also said that it was much
    faster to install labor-wise since you're doing a 20"x40" area at a
    whack. If you were having it done, the lesser labor was supposed to
    compensate for the more expensive material.
    
    	The material was formed and colored to look like ceder shingles.
    Even the width looked similar. I believe it also carried some minimal 
    R-value. It also had a 50 year warranty. I'm not sure if this would be 
    any better or worse as far as ice dams are concerned though.
    
    	Ray

I just called my insurance company (Amica) to file a claim for the water
damage.  I was told that they'll also pay the bill for having the roof
shoveled off after the damage occurred; nice of them!

				Steve

re: .176

So did ours (Sentry/Middlesex).  The adjuster even said he would give us
an allowance for getting the carpets cleaned, although we haven't 
detected any noticeable damage yet (too early to detect mildew).  

   Gary

    The "gutter/no gutter" controversy seems to border on the religious :^).
     
    I have seamless aluminum gutters along both front and back, and get
    very nervous seeing the ice start to build up. Unfortunately, the
    gutters are part of my defense system to prevent a wet basement. Since
    the roofline is simple and the height's not that big a deal (your
    standard 40' split-level ranch)I've been kicking around the idea of
    making the gutters removable: I'd take 'em down in November, and put
    them back in late March/early April.
    
    Anyone ever try this? any comments, suggestions, tips or cautions?
    
    Just fishin' for feedback.
    
    Freddie

    RE: .178
    
    Do *not* remove the gutters.
    
    Marc H.

    
    Has anyone had any experience with filing homeowners claims for 
    water damage due to ice dams?  I have a three-season porch which
    is leaking like a sieve.  The couch is so full of water that it
    sloshes when I tried to move it.  There are icicles (water actually
    since the recent thaw) coming out of the light fixtures, light 
    switches, electrical outlets, etc. but I'm afraid that much of the 
    damage is invisible and/or will be invisible by the time an adjuster
    gets out to see it.  It would be helpful if I knew what to make 
    sure they've included in their estimate - i.e. will electrical outlets
    just dry out on their own?  Will the material under the siding need
    to be looked at? 
    
    

    I just went thru the claim process.  I had water leaking into a
    bedroom and dining room.  There was water damage to hard wood floors
    and all the wood trim around the window.  Personal belongings were
    also damaged.  We filed a claim for damage to the floors and wood trim
    only as we learned that personal belongings were not covered for leaks
    from the roof.  However they are covered if a pipe bursts.
    
    As far as damage inside the wall the adjuster said anything that got
    wet in the wall would dry out eventually and there was no claim made
    for that.
    
    Good luck, Mark

>     As far as damage inside the wall the adjuster said anything that got
>     wet in the wall would dry out eventually and there was no claim made
>     for that.

	The insulation may eventually dry out, but it's R value
	I believe will be noticeably decreased where it had been wet...

Some policies do cover damage to personal belongings caused by roof leaks, etc.
Mine does, anyway. 

				Steve

    re:.179
    
    care to elaborate?

They come down for winter and back up for the remainder of the year. They're
designed to be used this way and the switchover appears to be pretty easy.
All the houses do have really good draining soil, perimeter drains, etc.

						Trace

    I'm in the market to buy about 75' maybe of cable or heat tape to
    place inside a gutter which will be put up in a couple weeks.  However
    it seems this item is seasonal and I haven't found it at places like
    Home Depot or Somerville Lumber.  any ideas?  would it be a heating
    product or a plumbing product? 
    
    c
    

Heating, plumbing, roofing, or electrical.  At Home Depot
I believe it was kept in electrical, but ordered by plumbing.

Good luck getting 75'.  You may need to special order it.

  Gary

I aaw 80' lengths at Wal-Mart, but they probably consider it seasonal and
don't have it out now.

				Steve

    At the Salem NH, Home Depot, it was a roofing product and was with the
    gutters and downspout pieces.
    
    	Dave.

By the way, we followed the directions on one of the boxes and
computed a requirement of 136 feet.  The boxes we saw all used
a minimum multiplier of 4, giving us 4 x 34ft.  None allowed
for the possibility of an overhang less than one foot.

Does this seem right?  34ft isn't exactly a long roof line.

   Gary

    I saw a kit for 120' at a TrueValue store the other day for $98.
    They had other lengths available too.
    
    -TB

.161>Metal roofing along the roof eaves is a fairly common sight in New
>    England to prevent leaks from ice dams. So, yes it can be used on a
>    house (you expected them to be used on cars, maybe?). A similar solution
    
    After a disastrous encounter with ice dams last year I've decided to
    add some ice belting to my roof this year.
    
    As I recall installation is pretty simple at least for me, with just
    one wide flat section to worry about. But since I'm no expert would
    anyone care to comment on whether I should use common or galvanized
    nails? I'm going to tar over the nails anyway and there's *nobody*
    (except an occasional pilot) who will see the roof. But I don't know
    if there's any inherent advantage in either one...
    
      John

>    anyone care to comment on whether I should use common or galvanized
>    nails? I'm going to tar over the nails anyway and there's *nobody*
 
	    Galvanized nails are only a little more expensive than non.
	Why risk corrosion?

					Tim

    Galvanized, without a doubt.  If you can, get the hot-dipped
    galvanized; they're still available, made in Canada, but hard 
    to find. 
    My experience with the made-in-the-far-east electroplate variety 
    has not been all that good.  The heads come off, and they rust
    anyway.

    Any good sightings of:
    
    a) roof rakes
    b) heat cables?
    
    I need to get a couple 100-foot-ish cable kits to avoid troubles on 
    one side of my house this year (the eave is about 25' up, and with 
    the greenhouse window I really don't want to try to do that with a 
    roof rake.. but the front of the house would do fine with a rake..)
    
    I've seen 60' cable kits at Home Depot, but nothing longer.. 
    
    ...tom

   Try Butler Lumber, Maynard.  I thought I saw 100' there...
   
   - Tom

I picked up 120' and 160' cables at Hammar Hardware in Nashua NH last Saturday.
120' was about $65,  the 160' was about $85.

				-- Stan

    How are these cables installed?  Do you run a zig-zag pattern over the
    gutters and up the roof?  How far up?  How large should the pattern be
    in feet or inches?  
    
    How much cable would be needed for a 36' gutter?  Do you just plug it
    into an outlet when you need to use it?
    
    Thanks!  Mark

��           <<< Note 736.192 by BUSY::CLEMENT "Smells like Nirvana" >>>
��                          -< how to install cables? >-

��    How are these cables installed?  Do you run a zig-zag pattern over the
��    gutters and up the roof?  How far up?  How large should the pattern be
��    in feet or inches?  

    The idea of these cables is not to melt ice dams, but to melt
    channels under any ice dam, so any more water coming down the
    roof doesn't get added to the ice dam, but runs under it, and
    off the roof.  Sort of like a pipe running under a road.

    So, 'how far up the roof'?  Further than you expect any ice
    dam to build up.   Typically three feet.  The bottom of the
    zip-zag patter has to extend off the edge of the roof --
    that's the idea, make a channel off the roof for new water to
    run through.

    If you run them over the gutters, it will look like hell. 

��    How much cable would be needed for a 36' gutter?  Do you just plug it
    Is this a trick question?   36 feet?

    If you have downspouts, you might want to run the heat tape
    within the gutter, and down the downspout.

    You should keep in mind, that this stuff is not cheap to run,
    and it might be easier to fix whatever is causing the melting
    leading to the ice dams building up.

    No, it's not a trick question.  The packages tell you how much
    cable to use for a given length of roof or gutter.  My recollection
    is that you add 50%.  The idea is, as Lee says, to form channels
    through which water will drain, but 3' isn't usually necessary, unless
    you have a large overhang.  I think about a foot past the overhang
    will do it, but check the packages for more detailed instructions.
    
    If you run it in the gutter itself, you should also run it down the
    downspout and ground the downspout (according to the instructions).
    
    					Steve

��     <<< Note 736.194 by QUARK::LIONEL "Free advice is worth every cent" >>>

��    No, it's not a trick question.  The packages tell you how much
��    cable to use for a given length of roof or gutter.  My recollection

    I was thinking that there were two things here -- the heat
    tape being used in a zig-zag to melt channels in any ice-dam,
    and heat tape in the gutters/downspout.

    Since I am running a zig-zag pattern I was wondering how much length I
    would need for a 36' length of roof.  This pattern can use 2' or more
    of cable for every linear foot.
    
    So assuming 2'.  I would need 72' of cable plus another 8 feet to reach
    the outlet.  Total of 80'.  
    
    You mention "tape".  Is it tape or cable or both?
    
    I thought (and I have not even looked at a box or directions yet) the
    cable needed to cover both the roof shingles and overhang into the
    gutters.  
    
    I don;t know how to correct the cause of the ice dams.  In 7 years of
    living in this house, last year was the first year of ice dams and we
    had floods coming into our house which damaged wood flooring, window
    treatments, personal property, etc.
    
    Maybe I can find a roof rake now before winter starts.
    
    All the snow just stayed on the roof all winter, and when melting temps
    hit we had water coming in all over the place.
    
    This cable is going to look ugly, especially that part that has to
    travel down the front of the white vinyl siding to meet the outlet box.
    
    Mark

.196> Since I am running a zig-zag pattern I was wondering how much length I
.196> would need for a 36' length of roof.  This pattern can use 2' or more
.196> of cable for every linear foot.
    
    Depends on how much you "zig". The "1.5 times the length of the roof
                                line" rule assumes that angle A in this
          ^         ^       D   zig-zag pattern is 90�. In that case, the
         / \       / \      |   amount of cable needed to get from point
        / A \     /   \     |   B up to the top of the triangle and down to
       /     \   /     \    |   point C is approximately 1.4142135623731
      /       \ /       \   |   times the straignt line from point B to
     V         V         V  E   point C, so 1.5 is a good, slightly 
     B---------C                conservative estimate. Also note that for
                                90� angles, length D-E is the same as
    length B-C. So, if you want to go 2' up the roof, measure out 2'
    intervals for the bottoms of your zigs and maintain 90� angles; if you
    want to go 3' up the roof, measure out 3' bases and still maintain the
    right angles. In either case, you will need ((36*1.41...)+8)' of
    cable.
    
    If you use an angle of less than 90�, you will need more cable. An
    angle can be calculated that will use all the cable you buy.
    

    I saw a couple roof rakes listed in the most recent Large
    catagalog from Northern Hydralics
    
         Dean

    This is our first year in the new house.  We have aluminum gutters and
    to be safe I'm planning on putting heat tape in the gutters and
    downspouts.  I'm not planning on doing the eves as they don't hang over
    that much.  Does this sound reasonable?
    
    Also, I have three rakes that extend out 1-2 feet (looks real nice). 
    Should I be concerned about ice dams here?
    
    Thanks, 
    Bill
    

    If one doesnt have any eaves (as we do on our shed) 
    is it best just to use heat tape in the gutter as (-.1)
    suggest or would the /\/\/\/\ heat wire on the roof/gutter
    edge still be the better solution?
    
    -Brian

    Well, last year I was GOING TO put up Ice Belting (even bought the
    galvanized nails :-) but couldn't find the aluminum panels anywhere.
    
    So for those hunting around SoNH here's the scoop: Home Depot in South
    Nashua has Ice Panels for sale for $7.50 each. Each panel is 30 inches
    wide and the inventory is located across the aisle from the display,
    maybe 12 feet away. Stock number is 506315. If last year is any
    indication, they won't stay in stock very long.
    
      John

    Well. I guess its my turn to deal with ice dams. I've reviewed the
    preceeding 295 replies and have a pretty good idea how I need to
    tackle the situation short and longterm. I'll state the problem
    and I ask for your further valued critique.
    
    I have a cape style home approx. 36ft in length. The front of the house
    is north facing w/ a rain gutter running the entire front of the house.
    I have a dam that has fully consumed the gutter and has backed up
    approx. 1.5 to 2 ft (maybe further) onto the roof and is about 1 ft thick
    of ice. Ice has backed up into the soffit and the melt is dripping in a
    few places. One area is between where the soffit meets the siding. Water is
    dripping here and behind the siding. Interior problems are minimal.
    Water is dripping between the front living room picture window and its
    storm collecting on the sash. Some is draining out the front of the
    storm but its starting to back up into the interior window trim. I've
    also got water coming between the front door and its storm. What
    started primarily on the right side front of the house (pic window
    area) is now moving left with varying degree's of runoff on the outside
    of the siding, in both liquid and frozen form. As of yesterday, the
    water was dripping onto and around the garage (1 bay under) door
    casing. Like I said, nothing has of yet (I haven't gotten home today 
    though) gotten to the interior but I can just feel I have a major
    disaster waiting to happen if I don't get rid of the dam quickly.
    
    The possibilities -
    I'd like to stay clear of the hot water treatment. The pitch of the
    roof (?o) is such that I'm not going up on the roof (maybe I can get
    the Drifter's to go up there 8-). 
    
    I'm planning the wire/cable method. Since the gutter is one of the
    problems for the dam in the first place, I'd like to incorporate it in
    the wire placement. Will just hanging it over the dam/gutter help? 
    
    Should I consider getting a professional to help? Anyone know a rep. 
    contractor(s) in the Leominster,Ma area?
    
    Thanks,
    George
    
    

I ran my cable up through the downspout, through the gutter to the far end, 
then up and down the eaves all the way back to the downspout.

I DON'T run it if it's not snowing.  I only turn it on when it's snowing to 
prevent the "blanket" of snow forming in the first place.

It doesn't work "perfectly" but it does keep a hole open in the downspout 
when it snows.  (Probably, because I forgot to turn it on during the first 
heavy snow storm we had a few weeks ago.)

Ice still forms on the gutters, but it doesn't back up onto the roof.

    Re: -1
    
    Thanks Skip. Now all I have to do is pick or drill a hole where the ice
    is clogging the downspout to run the cable through.
    
    /George

    I've been thinking of putting up a heating cable, too - this is the
    first year since I put up the gutters (something like 16 years ago now)
    that I've had a major ice dam problem.  Luckily, there hasn't been any
    water inside the house, or inside the picture window, but I do have
    icicles everywhere, and a lot of ice from where they have dripped onto
    the steps and driveway and refrozen - which is reason I put up gutters
    in the first place.  It's not just the gutter that are full of ice -
    the whole roof is covered with it, especially the north side.  I guess
    what happened is that the first snow storm, while I was on vacation,
    left a big accumulation of snow that was followed by some real wet snow
    or maybe some rain on top, which all then froze in place - I had a real
    nice mess to clean out of my steep driveway when I got back in town,
    too; that's long since gone, but the gutters are full. I never get any
    leaves in the gutters (no trees, and my hillside location is very
    windy) so I don't think they are blocked by anything but the ice.
    
    /Charlotte

what type of contractor would one get for installing these heater wires?
electrician?  Where do the cables plug in?  Where are the on/off controls?

I have finally convinced myself the insulation/ventilation approach is not 
going to help on my house.  I just had a roofer person inspect the attic and 
was told it is ventilated fine.  He says my ice dam problems are a 
combination of the minimal roof pitch, too many pine trees/too little
sun, and the type of storms we've had.  I was thinking of adding more
soffit vents to enhance the strip soffit venting there now.  He said
it would not help.  

I give in.  I am ready for the heater cables.

Previous replies indicate they can be put over snow/ice.  What about
after channels are cut through the ice to provide water escape routes?
I had these channels 2 years ago and it looked like a maze up there.  
Will the cables be okay?  Are they secured to anything?

-Wendy

p.s. the roof guys are up there now chopping away.  what horrible
sounds it makes!

    Well, when I was a kid, my father installed the heat cables himself -
    during the summer, being a forward-thinking sort.  He put the switch
    for them right above the thermostat for the furnace, that being a
    convenient place to get wires to from the attic as well as someplace
    where whoever was home during a storm might look and so might think to
    turn on the wires.  That house was heavily shaded by oak trees on the
    north side that didn't usually lose their leaves until almost spring,
    so any ice accumulation on that side of the roof was usually around for
    the whole winter.  I think the wires were tacked to the roof somehow,
    but I don't remember.  My dad was both an electrical engineering
    professor, and a licensed electrician.  I expect that legally speaking
    you have to hire an electrician to install the things, at least if you
    are going to connect them permanently to the house wiring.  I would
    need an ice axe to do any work on my roof right now anyhow, though, so
    unless I start getting water inside, I'm not going to do anything yet.
    I have both soffit vents and lots of insulation in the attic (15 1/2"),
    and have never had ice dams before this season, so I think it is just
    the weather.
    
    /Charlotte

The cables have a simple 15 amp, two prong plug.  They plug into ant duplex 
socket or extension cord.

If you want to or need to put a duplex box outside, you'd need an 
electrician to do it legally.  If you already have a GFI circuit outside, 
use a heavy duty extension cord and trudge out into the snow to plug it in 
whenever you need to use it.

FWIW, if you put a switch on an inside wall to control the GFI box on the 
outside you'll have to go out and make sure the breaker didn't trip when 
you flipped the switch, anyways.

    I'm older than you think, I guess: there WEREN'T GFI circuits at the
    long-ago time when dad installed the cables...  I think all he did was
    run their cable into the attic and install an outlet up there
    controlled by the switch he put in.  In fact, the outdoor outlets my
    house has don't have GFI either - I live in an older place.  I'll
    probably get someone to put in a similar arrangement - later in the
    season when it becomes possible to get up on the roof!  (Even the solar
    hot water heater panels are buried under ice - we started noticing that
    we weren't getting the accustomed preheated water out of that device
    into the gas-fired water heater, and took a look at it.  It's a real
    icy mess up there...)
    
    /Charlotte

    I have a nice example of ice damming on my roof. The cause is 
    inadequate ventilation/insulation which I'm in the process of 
    correcting. However, right now there are icicles forming between
    the gutter and the soffit area where the gutter attaches to the house.
    (The current weather is in the 30's and there is about 6" snow on the
    roof.) Coinciding with the formation of these icicles, brown colored drip
    marks have formed on the house siding below the icicles. They have left
    what looks like permanent stains on the paint. I presume the stains are
    drips from the icicles, that touch the house when the wind blows, (the
    overhang is only about 12 in. or so), but presuming that to be the
    case, I don't know why they are brown.  Anyone care to hazard a guess?
    
    thx, 
    
    -Barry

I asked the same question last year.  See answers to .130 in this note.

Btw, the status of your ice dams sounds like they are close to
making an entry into the living space.  Mine did eventually.  Just 
a matter of time.

    Thanks for the pointer to earlier notes, but I don't think the question
    was answered, except for "brown=sawdust", which doesn't sound right
    to me. I am hoping someone else has an idea. 
    
    > Btw, the status of your ice dams sounds like they are close to
    > making an entry into the living space.  Mine did eventually.  Just
    > a matter of time.
    
    When you say eventually, you mean eventually with that particular pile
    of snow, or eventually that year? 

The other possibility for the brown stain is rust, from the nails used to 
roof the house (which should be galvinized, but that's just a coating which
could break).  And eventually does mean this snow pack, rather than sometime
later this year.  Sigh...  Just noticed icicles forming against the
house this morning, a good foot or so from the overhang of the roof.
Which means its probably going to be evident inside the house all too
soon.  Might have to do some chopping tomorrow while I'm home.


PeterT

>    When you say eventually, you mean eventually with that particular pile
>    of snow, or eventually that year? 

I eventually had a leak that year..  I forget if the spot that leaked
was the only area with brown drip marks or not.  It certainly had the
most brown marks because I remember washing them off the next summer. 

(btw, they came off nicely with a tsp solution and hose sprayer).  

I had the ice cleared off the roof before the other trouble spots had a 
chance to find the inside surfaces.  I remember hearing the dripping in 
the walls near windows, knowing it was getting closer.

a ridge-vent, rafter-vents and 22 mos later, I am back in the same
situation!  

Gotta luv winter!

    A guy I work with used rock salt a few years ago when water started
    coming into his house. He said he had good luck with it.  Can anyone 
    suggest a reason (or two) why you shouldn't try this ?  I don't have 
    any problems now (new roof, moisture barrier and properly vented) and 
    don't forsee any but it doesn't hurt to be prepared.
    
    
    		Dean

	I connected a hose to the hot water outlet of the washing machine
and melted all of my gutters last week. Worked pretty good. Fortunately I
only have a racnch single story house, I can't see trying this with a 2 or 
more story house.

To reiterate a few notes back (.3, .120), Bird's Water and Ice
Seal is a godsend.  I had several thousand $$ ice damage from the
wonderful winter two years ago. We've a gambrel with a flat face
facing north (verrry shallow pitch) == lots of ice dams.

When I had the roof redone a year and a half ago, I had them 
install 6 ft of BWI.  Despite the sizable dam on my roof (and
6 ft icicles hanging down), I've had zero problems.

Tom

    Update to .296
    
    Well I decided to take yesterday off to tackle my ice dam and clogged
    gutters. I did buy a 100ft ice cable but only have it partially
    installed. I spent the better part of the day doing my best impression
    of Edward Scissorhands with a wood chisel. A few folks recommended
    using the claw end of a hammer but that was futile at best. For the
    most part, the chisel did an admirable job though time consuming.
    
    I was able to chop 2/3rd's the length of the house and removed the
    bulge into the gutters. The tough part was that I have a one under
    garage and once I hit the driveway wall I had loads of fun positioning
    the ladder. The ice is the gutters is now flat or a little
    under the rim of the gutter. I also placed ice melt in the gutter. 
    
    Saturday I'll finish chopping out the rest of the gutter and run the
    cable along the length of the gutter and over the rest of the dam. 
    
    Sore but getting there,
    George

    Re -.1 try a hachet faster and just as effective
    
    yea Birds ice and water seal thats what I meant to say
    
    
    		Dean

    
    re: .302, plugging ice melt cables into extension cords.
    
        All the cables sets I've seen expressly warn against using any
    	extension cords. Home Mechanix (I think) about two years ago 
    	mentioned that improper installation of ice melt cabling will 
    	nullify your insuarnce, if something should happen.
    
    re: last few...
    
        My favorite ice dam tool:  mason's hammer.
    
    								- Mac 

How do you people who recommend mayhem in clearing ice (mason's hammers,
claw hammers, wood chisels) keep from ripping up the first course of
shingles at the edge of the roof?
My experience has been that the ice frozen around the drip edge has a pretty 
fierce grip on those shingles, and random bashing cracks the cold shingles
and breaks off chunks.
I did that a few times and learned that the only safe ice I could remove 
was that not touching a shingle, unless I was VERY careful.
I use only my gloved hands for most of this work.  (Or a snow shovel
if I get up there soon enough.)

- tom]

    I just spent a few hours chipping away at some ice dams on Sat using
    a claw hammer.. I would use the claw when there was more than an inch
    or two before hitting the shingles. THen I would use the flat hammer
    to pound away at the rest. Suprisingly the flat part did pretty well..
    The other thing that helped was the sun warming up the shingles towards
    the middle of the day. By that time I was using the flat hammer and
    breaking off big chunks because the ice was just separating from the
    shingles.  By the end of the day, I had broken only 1 2-3" piece of
    shingle off a roof that had two layers anyway.
    
    I use a snow rake but, of course, this was on a house that hadn't been
    raked yet.
    
    -Gary

    We did get a few hours above freezing over the long weekend, but the
    only useful thing that did around my house was that a corner of the
    solar hot water panels melted out, so the panels started up and cleared
    themselves - which is goodness since the gas-fired system by itself only
    holds 32 gallons of water; without the solar preheat tank behind it
    (another 80 gallons) we sometimes run out of hot water.  The roof,
    though, still has many inches of snow/ice on it everywhere else.  I was
    looking at the neighborhood houses yesterday, and noticing that the
    house across the street, which has no insulation at all in the attic,
    is now completely cleared, the house next to it with a little
    insulation still has ice but no snow, and houses like mine where lots
    of insulation was added have 12" of snow still!  Almost makes me wish
    for once that I didn't insulate and vent the attic, though I'm sure my
    heating bill is much lower than the house across the street.  I still
    don't have any water coming in, anyhow.  Raking the snow off wasn't an
    option - I was on vacation when it and the ice on top of it arrived, so
    it was all a solid mess before I even saw it.  Sigh.  With another
    blizzard expected this evening, it's just going to have to get by on
    its own, since I couldn't figure out any safe way to try to clean it up
    over the weekend - roof is too steep to try to shovel, plus right now
    you'd need an ice axe to even get up on it at all.  Ycch, I hate
    winter...
    
    /Charlotte

    Re - How do you keep from damaging,etc....
    
    I'm fortunate enough (actually its pretty ugly so maybe I'm not
    fortunate) to have ice belting so my chisel doesn't actually come
    in contact with any shingles.
    
    Saturday I finished clearing the ice overflow in the gutters. Putting ice 
    melt in the gutter really helped. By Sunday AM the gutter was flowing 
    again. Sunday PM all the ice (quite a bit of it) on the belting slid
    off the roof. I forgot to take my flag and flag pole off the outside of
    the house and the pole/mount was ripped from the siding by the falling
    ice. I would have though the pole would have snapped first but it didn't.
    
    Luckily I've seen no visible signs of interior damage due to water. But
    time will tell!
    
    Now I'll just have to get a snow rake so this doesn't happen again.
    
    /George 

re: .317

The houses with warm (uninsulated) attics are now snow free,
yet your (well insulated) attic is not?  Is your attic insulated
on the eaves, or only the attic floor?  If the latter, maybe 
this is a bad idea, but ... a (supervised) electric heater in 
the attic might be worth a shot ...  

Re: .319

Why are you astonished?  That's the way it usually works.  The best situation
is to have a thick layer of snow and no icicles or ice dam - that means that
the roof is staying cold.  The snow itself is a good insulator.

				Steve

re .319:

.320 is correct, and what you suggest is just the opposite what you want.

An ice dam forms as follows:  Snow on roof starts to melt from heated attic,
water runs down and reaches eaves.  Since there is no attic below to heat
it here, the water freezes.  Further water builds up as ice and voila, ice
dam.  Now water stopped by the dam will pool and flow through the shingles
into the attic, the walls, etc.
 

>water runs down and reaches eaves.  Since there is no attic below to heat
>it here, the water freezes.  

...or in my case, there's a well-insulated walk-in closet running the 
length of the eaves on the northwestern side of my house.  Additionally, the 
lower portion of the roof is shielded from the south by the roof on the main 
portion of my house (peaks are at right angles)

Snow melts on the top half of the roof and reaches the well-insulated 
closet ceiling and starts building an ice dam 6 feet up the roofline.

Fortunately, most of that roof gets hit by the noontime/afternoon sun but 
the valley, now THAT'S a different story.

A roof rake and heater cables is the only solution.

Of course, that snow-followed-by-rain storm we had about a month ago didn't 
help matters.  The ice dams never really got a foothold but it was getting 
mighty close.  What little ice there was between the coils chipped off 
easily with a hatchet.  Since there was a lot of bare roof around these 
patches, they were nearly free of the shingles, anyways.

Ice dams can appear even when there is little/no heat loss through the attic.
The sun "compresses" the snow pack on a roof through low level heating
resulting in runoff at the roof.  If it is at or just below freezing at the
eaves, and especially if the eave is in shadows, the drips begin to freeze and
back up. 

The safest way to remove an ice dam is to spray it with warm_to_hot water.  
People who use hammers and hatchets (shivverrrr), usually pay for it by 
replacing shingles in the summer after they soften up and break off.

About the best way to never(seldom) have to worry about ice dams is to install
heater wires in the fall. This was not done to the very well insulated house we
bought last year - it WILL be done before next winter (I used the hot water
treatment, last week). Heater wires can cause monstrous icicles, often going
from eave to ground.  But they preclude ice dams. Although a rood rake will do
the job, you have to wander outside and work in not_nice weather and it is
difficult to get the 2nd and 3rd story roofs. 

As Always, For What It's Worth.....

Dave

    My husband hooked up our power washer to the hot water line on his
    uncle's washing machine to clear his uncle's roof of the ice dams. Took
    about 20 minutes to get channels cut and by the afternoon, all the ice
    had fallen off. This is on a Cape-style house.
    
    Debbie
    

.320: Why are you astonished?

I'm not astonished...the principal is very simple.
Yet two years ago, my attic was extremely well-insulated
(by the previous owners)... two layers on the attic floor, 
and I had tons of snow _and_ colossal ice dams. ( .317
described the same basic problem.)  

Back then, I heated the attic with the idea of softening
the bottom ice. A couple hours later, my friend and I tied
in with our climbing gear on the roof and cleaned off the 
whole roof.  We never established whether warming the attic
had a neutral, positive, or negative spin on the whole task.

As a sole solution, however, in retrospect, I agree its a
bad idea.  As .321 points out, all it would accomplish is 
keep melting the snow on top of the ice.

Tom

I also had to chip away at a large ice dam last week and installed heating 
cables.  When I bought tyhe heating cable the box said to take the length of the
roof and multiply it by 4 for a 12" eave.  Since I had a 30 ft  section of roof
I was working on I bought a 120 ft cable (no gutter).  When I put it up,
following the instructions, I had about 45 feet of cable left over.  Anyone else
find the box instructions to be wrong or did I miss something? I went back and
bought an 80 ft cable and that worked out fine.  I installed itn the recommended 
triangular pattern.

George

Re: .310
> 	I connected a hose to the hot water outlet of the washing machine...

	Funny, my washing machine only has a drain pipe and a hot&cold water
	inlets :-)

    which begs asking: ... is an electric receptacle an inlet or an outlet?

Re: .325

But how well ventilated was your attic?  Most older homes have very poor
attic ventilation.

				Steve

re: .329

At the time, it had (3" diameter) soffit vents every 5" or so, and two 
square vents (approx. 1.5' X 1.5') on the side of the house.  No ridge
vent.  Its quite possible the soffit vents were iced over, as well...

           re: .326

           George,

           What amperage were these cables drawing?  Does one need a
           seperate line/breaker?

           Steve

    Has anybody had to hire roofers to remove snow and ice dams from their
    roofs this winter. We were getting significant water penetration inside 
    from ice dams along a cathedral roof and bay window area.
    
    Admittedly I was desparate to get the ice dams removed and I wasn't
    about to climb a ladder onto a second story roof. I contacted Mathew
    Fair (MJF Gutters and Roofing) who did the job a day later than
    promised and charged $50/hr per man. The three man crew worked 2.5 hours
    with shovels, claw hammers and sledge hammers...... final bill was
    $350.
    
    Now I realize that this may be considered hazardous duty pay.....and
    trademen will charge what the market will bare in "emergency
    conditions" but are these prices way beyond the reasonableness or am I
    just out of touch with trade labor rates.
    
    Any recent comparative prices or experiencees??
    
    Thx,
    
    JBS 

>     Now I realize that this may be considered hazardous duty pay.....

	Speaking of which, I would of also made sure the company
	and all workers were insured (the last thing you need is
	a lawsuit against your homeowners insurance if one of them
	falls off the roof or ladder ....)

That's how my boss got the ice dams off his roof, too.  fifty bucks an hour
.

He's already busted up a foot pretty badly from a previous ladder incident 
so he's not about to go up on an icy ladder to chop the roof up.

We probably are not comparing apples to apples, but I paid $65 last
week.  (2 years ago, the same outfit charged $50).   It is a professional 
roofing outfit (yellow pages said "licensed and insured" - I didn't probe
for particulars). 

They made "channels" in the ice dams and removed snow about 3' up. 
There's about 6 or 7 channels across each of the front and rear edges. 
Each channel is about 1' wide.  I'm not sure how deep the ice dams
were.  The interior damage had not started but it was close.  I could 
hear water dripping and some windows were icing!

There were 2 guys and they were on the roof about 45 minutes.  They
also did a good job shoveling the walk and driveway where ice and snow 
fell.    I have a shallow pitched roof.

Cal's Roofing & Construction, Pepperell.

Also another roofer had quoted $100 but never showed up.

> Also another roofer had quoted $100 but never showed up.

	An hour or flat fee?

$100 flat fee.   The $65 was also flat fee.

    I had Chick Beaulieu (Nashua, our roofer) do this a couple of years ago
    when we had ice force its way into the soffit then melt, causing water
    damage.  The flat price was about $150.
    
    				Steve

I just got a call from the Chimney Sweep we use; Son's in Milford, NH.  They
want $80-$100 (depending on size of house) to clean snow off all eaves going
back 4 ft; $350-$400 to clean snow off the whole roof. I did not ask about ice
dams. 

    The $350 was charged was to shovel the entire roof (except attacthed
    garage and unheated 3 season room) and remove the ice dams (> 6" thick)
    from all roof edges.
    
    I'm now using a roof rake after each 2-4" of snowfall to try try and
    keep the lower 3' of roof line clean.......hopefully this will
    eliminate the need for another $350 ice dam surgery.
    
    JBS  

    Can someone tell me exactly how the roof rake works.  I'm assuming that
    the roof rake is designed like a regular rake (only stronger).
    
    My question is:  Do you stand at the foot of the house and use the rake
    or lean out the windows or get on the roof or stand on a ladder.
    
    How expensive is a roof rake?
    
    Gita

    The roof rake I bought came with 3 six foot aluminum pole section that
    attacth to on another by inserting end to end with a locking button
    similar to what you'd find on umbrella.
    
    The rake is approvimately 24" wide mde of plastic and uses the same
    button & tube connection to the pole end. There are also 2 angle
    brakets that come off the pole to each end of the rake to give it
    added rigidity. The rake doesn't have teeth like a garden rake but
    is really more like a solid squeegee. The mounting pipe on the rake
    itself has a slight bend so that it "addresses" the roof angle
    compensating for your perpendicular position on the ground.
    
    Cost for the rake with 3 sections was $52 plus $9 for an additional
    6 foot pool extension which I needed to reach my second story.
    
       +\     (shows attachment angle between rake and pole)
      /  \
     /    \
    X      \
            \
             \
              \
               \
                \
                 \
    
    
    
    |         (flat top view view of rake assembly)         
    |\         
    | \         
    |=====+===========+============+===========+
    | /
    |/
    |
    

If you are going to buy one, Hammar Hardware in Nashua has all aluminum ones
that are long enough to reach the roof on a 2 story colonial for about $50 -
$55.  Might be more duable than the plastic/aluminum variety.

George

HD (Nashua NH) was selling them for ~40.00 - I think total length is 24' -
which can just reach the roof of my 2 story cape - its the al/plastic model 
described in .342 - it does not have much strength at its full length.

bjm

    
    I bought extra sections and put a long arcing bend in one section so 
    I can reach up over the eaves on the (very high) shallow sloped rear 
    roof of my house. That way, with the pole nearly vertical I can still 
    reach 4' back on the roof.
    
    I have the vinyl/plastic bladed version, which is breaking after two
    years of serious abuse. 
    
                                                               - Mac 
    
    

I have an enormous ice dam forming above my garage next to the main house and
it is causing problems.  I need a roofer to make recommendations and fix it...
Chances are I need to rip out the useless Hicks vents and put in soffit vents,
maybe use an ice shield...

Please, can anyone recommend a good/trustworthy roofer who works in the 
Westford area?

Thanks,
-Tamar

    
    see note 2027
    

     I just got the AL pole w/plastic rake version at Spag's for $25.  I
     think it's 18' feet long.

     Bill

    Bought a wooden one last spring (clearance) for $35.  A friend borrowed
    it and broke it the plastic "rake."  He went to Walmart and replaced it
    for $30, with an aluminum one - same length as the original (18'). 
    It's much lighter and other than the "hazard warning" for electrical
    wires, is much better.

Something I've done to my aluminum rake is to screw a rubber door sweep to the
leading edge, with the rubber protruding a quarter inch or so.  It doesn't seem
to hurt the snow-removal ability and makes me feel that I've helped avoid
damaging the roof by scraping with the metal edge.  I sent this in to 
The Family Handyman a couple of years ago - they printed it and sent me $100!

				Steve

I've been told that gutters help cause ice dams, but couldn't figure out 
why -- until this year.

We have 'Hicks' style soffit vents (along the roof drip edge), ridge vents,
and gutters.  We also have a lot of oak trees which shed their leaves late, so 
I didn't bother to clean the gutters before the first snowfall this year.  Heck,
it was late November & the snow would melt & I'd have plenty of time to do it,
right????

Wrong!  The clogged gutters, abundance of snow, and freeze/thaw cycles caused
a huge ice dam extending from the gutters onto the roof.  Guess what: my Hicks
style soffit vents were totally encased in the ice dam, effectively eliminating 
the soffit vents, causing a warmer attic, leading to more ice, etc.

Fortunately I think I got to it in time (totally chipped away the ice and
cleared out 3/4 of my gutters - all except for one section which is difficult
to access - still working on this one).

This summer I'm going to seriously think about adding separate soffit vents 
UNDER the soffit.  If you have Hicks style soffit vents, watch out for this!

...Ken

I have the hicks vents (no gutters) and I've often heard conflicting 
opinions about them (here in HOMEWORK and out there).

I asked the roofer, who was here 2 weeks ago chopping ice dams, if
the hicks vents were sufficient to ventilate the attic or if I should 
install regular soffitt vents. He said the hicks vents are the best!!  

Can you imagine a contractor turning down potential work?  He must have 
really believed in the hicks vents.  He said more soffitt vents won't change
anything.   He blames my ice dams on shallow pitch, lack of sun,
type of weather, etc.

However, the roofer who installed the ridge vent 2 years ago, 
wanted to also install additional soffit venting at the time because 
he said the hicks vents were not good enough.

Meanwhile my niece-in-law was telling me that she recently went up
in their attic for storage retrieval and it was sooooo cold she could 
see her breath.  No ice dams on that house.  I'll have to see if my
attic passes the breath test.

-Wendy

p.s. I recently saw Mr. Hicks pitching for some lumber company on local 
cable.  I wonder if he's still using these vents on new houses.

What exactly are Hicks vents?

BTW, today's (7-Jan) Boston Globe had a short description how ice dams form
and what to do about them.

    
    Hick's vents are a combination of drip edge and vents. Why someone
    would call them "the best" is unknown... a continuos vent under the 
    soffit could provide more air flow with NO chance of freezing over.
    I added 4" round vents in every other bay to try and help my Hick's
    vents this year.  
    
    Re: a couple back...
    
       Shallow pitch and Hicks vents is a bad combination regardless of
       what the roofer says. Installing Hicks vents on a shallow pitch
       requires closing the angle of the vents... nearly pinching them
       off (this was the problem on my house). Despite the fact that the
       vents are at least 1-2" across, when you pinch them shut and put
       the sheathing gap at such an angle you end up with all of a 1/4"
       of ventilation.
    
    								- Mac

    	I have what is known as a false Gamrel. I believe that they used
    the Hick's vents on the the upper part of the roof (shallow to steep 
    edge). It looks like that's all the could use as there isn't much space
    for anything else.
    
    	When it ever stops snowing and warms up long enough for me to clear
    my roof, I think I'm going to try to reconnect the heating wires the
    previous owner installed. One of the segments has a break, so I'll need
    to solder and reinsulate the wires and give it a shot.
    
    	Though we had ice dams last year, this is the first year we've had
    any significant leaks. The shingles are getting old and are in need of
    replacement. Come spring, I will be reshingling at least the upper
    section. Since this is a relatively shallow pitch, looks like I'll be
    going with the adhesive ice and snow shield material. 
    
    	I just caught the last of a segment of Home Time (?) and they were 
    using this. Looks like the way to go, at least on the upper (shallow)
    part of the roof anyway. I've heard the stuff is fairly expensive. On
    Home Time, they used it to cover a whole small porch roof. My guess is
    that only one or two courses of this are needed on the roof edge. It's
    about 3' wide. Any comments ?
    
    	Ray

    
    The width is dependent on the slope of the roof. Do a rough eyeball
    of horizontal line from the top of a nine inch dam would hit the 
    roof... this will give you a rough idea of a worst case water 
    buildup. Personally, I'd add an extra course beyond that... while the
    stuff is expensive (average is $75 per 3'x35')... it isn't much
    compared to the aggravation of leaks and ceiling repairs.
    
    							- Mac

You just get the honor of paying 30% more ($10) for it at HD.

>     soffit could provide more air flow with NO chance of freezing over.

    I don't think that the lack of air flow from a blocked hicks vent
    is going to significantly affect the forming of ice dams. I think
    that a properly insulated attic is more important here. 

    Charly

>                      <<< Note 50.357 by UHUH::TALCOTT >>>
>            -< BTW HD and Wal-Mart are selling the same snow rake >-
>
>You just get the honor of paying 30% more ($10) for it at HD.
    
    
    And, at least the Wal-Mart in Hudson, MA., is all out of them(as of last
    thursday or friday when I called).

>    I don't think that the lack of air flow from a blocked hicks vent
>    is going to significantly affect the forming of ice dams. I think
>    that a properly insulated attic is more important here. 

but what does "properly insulated" really mean?   If the goal
is to keep the attic cold enough to prevent roof snow melting from 
the bottom up via heat escape, then letting more cold air in has 
to be a good thing.  Can we ever reasonably insulate enough to completely 
maintain the r-value needed?  It seems to me that cold air intake has to be 
part of the ice-dam-prevention formula.    Also, lots of intake must be
needed to keep the flow going to keep the ridge vent clear.

Hick's now, but I'm going for more soffit venting next year.

> BTW HD and Wal-Mart are selling the same snow rake
> You just get the honor of paying 30% more ($10) for it at HD.

	Actually HD is giving you the better deal as HD will sell you
	that item for 10% *less* than Wal-Mart's price under their
	price matching policy (assuming your Wal-Mart is close enough
	to your Home Depot to be a "local" competitor, which is the
	case with the Hudson, NH Wal-Mart and Nashua, NH Home Depot)

>the bottom up via heat escape, then letting more cold air in has 
>to be a good thing.  Can we ever reasonably insulate enough to completely 

    True, but relatively speaking, a well insulted attic (R30+) is
    going to be cold, period. And it's also true that there will be
    heat escaping from a well insulated attic (insulation slows the
    transfer of heat, it's doesn't stop it) but I bet that the small
    slow escape of heat quickly mixes with the cold air in the attic
    and does not melt the snow.

> Also, lots of intake must be needed to keep the flow going to
> keep the ridge vent clear.

    I believe that the high volume of air that most people associated
    with a proper combination of hicks/soffit and ridge vent is more
    likely seen, and important, in the non snow-seasons, when the sun
    is shining on the exposed roof and you're trying to keep the attic
    and house cooler and dryer. It also helps prolong the life of the
    roof.

    Charly

    >True, but relatively speaking, a well insulted attic (R30+) is
    >going to be cold, period. And it's also true that there will be
    >heat escaping from a well insulated attic (insulation slows the
    >transfer of heat, it's doesn't stop it) but I bet that the small
    >slow escape of heat quickly mixes with the cold air in the attic
    >and does not melt the snow.
    
      Mixes with the cold air and then what? 
    
      Answer: Raises the temperature of that cold air slowly warming 
      the attic and causing snow melt. The function of the venting is 
      to remove that slowly warming air and replace it with more colder
      air to keep the "mixed air region colder.
    
      My HEAVILY insulated rear attic space is like an ice dam laboratory.
      Worst case is a heavy snowfall with crusty ice on top. Ice dams will
      slowly begin to form as long as the ridge vent is buried. As soon as
      the ridge emerges... The problem being that by that time, icicles have 
      formed blocking the Hicks vents unless I rake the leading edge of the 
      roof clear.  
    
      Pitch of the roof and orientation have much affect as well... but
      I've tracked down more articles on ice dams than you can imagine and
      they all state that most cases are solved by the proper combination
      of insulation AND ventilation.
    
      I'm waiting for an ice dam study from the University of Minnesota
      which is said to discuss more complicated ice dam problems and 
      prevention. If you want copy, send $1.50 and a request for the
      following 20 page book:  BU-0507/HM1295 to the following address:
    
                     MES Distribution Center
    		     University of Minnesota
                     1420 Eckles Ave, Dept HM1295
                     St. Paul, MN 55108
     
      Also consider including twenty five cents for FS1068/HM1295
      "Preventing Ice Dams on Houses".. a two page booklet.
    
    
                                                              - Mac
    

    I'm not totally discounting that blocked hicks or soffit vents can
    contribute to the problem. I just don't think that it's the
    totally-disasterious-must-be-fixed-imediately situation that some
    make it out to be.

>      Pitch of the roof and orientation have much affect as well... but
>      I've tracked down more articles on ice dams than you can imagine and
>      they all state that most cases are solved by the proper combination
>      of insulation AND ventilation.

    Yes, and then some. Even with everything done right, the weather
    can cause it. A particularly bad situation would be slightly below
    freezing temps with a strong sun. 

    More about insulation and other causes...

    I recently found three situations in my attic that were
    contributing to some ice dams forming.

    All of these were found about two weeks ago by observing the snow
    melt during the warm spell that we had. I noticed three sections
    on the roof where the melting was occurring faster as seen by the
    dips in snow cover. 

    One was a slight imperfection in the installation of some attic
    insulation. Even though I have 12"+ of fiberglass insulation, 2
    layers a right angles to each other, the snow melt was pointing to
    a section where there was a missing piece of the second layer. It
    was only about 1' long but it was right under one of the fast
    melting sections.

    The other two were related to a new bath room in the house. Both
    the ceiling vent fan exhaust pipe and the plumbing stack vent which
    rose up, then went horizontally across the attic to the back of
    the house before exiting through the roof were causing accelerated
    snow melt.

    I insulated both of these pipes and hopefully that'll fix those
    two problem areas.

    Charly

..........................................................................      
.                          Ceiling Airtightness                          .      
.                    Cold Climate Collection - Minn.                     .      
.                               Minnesota                                .      
..........................................................................      
                                                                                
This publication is part of the Cold Climate Collection from the Cold           
Climate Housing Information Center at the University of Minnesota.              
                                                                                
Ceiling Airtightness and the Role of Air Barriers and Vapor Retarders           
                                                                                
This publication is part of the Cold Climate Collection from the Cold           
Climate Housing Information Center at the University of Minnesota.              
                                                                                
Roger A. Peterson and                                                           
Lewis T. Hendricks                                                              
Cold Climate Housing Information Center, Univ. of Minnesota                     
                                                                                
Thermal Envelopes and Moisture Control                                          
                                                                                
    Insulated ceilings and walls that enclose heated space make up the          
thermal envelope of a house (see Figure 1).                                     
                                                                                
%G CEIL1A.PCX; Story and a half house.                                          
                                                                                
%G CEIL1B.PCX; Split level house.                                               
                                                                                
%G CEIL1C.PCX; Two Story house.                                                 
                                                                                
A vapor-retarder and air-barrier system is a necessary part of this             
thermal envelope.  A ceiling air-barrier and vapor-retarder system on           
the war side (interior) of the insulation is designed to stop movement          
of air and water vapor through the ceiling.  The principal function of a        
vapor retarder is to retard or control the passage of moisture as it            
diffuses through the assembly of materials in a ceiling.  Air barriers,         
on the other hand, serve to control air leakage.                                
                                                                                
    Warm humidified air tends to rise in a house, leaking through any           
unsealed openings in the ceiling, or diffusing through building                 
materials.  This results in the following problems:                             
                                                                                
1.  A wasteful, uncontrolled flow of warm air out of the house.                 
                                                                                
2.  A buildup of condensation in the attic or roof structure, resulting         
    in wet insulation and other water damage.                                   
                                                                                
3.  The warming of the underside of the roof, which causes snow to melt.        
    The water formed by this process runs down the roof and freezes at          
    the eaves.  Ice buildup at the eaves can cause water to collect on          
    the roof and back up under the shingles and through the roof.               
                                                                                
4.  The development of a low or even negative pressure in the lower             
    portions of the house, which can cause chimneys to draft poorly.            
                                                                                
5.  The diffusion of water vapor through ordinary ceiling plaster or            
    sheetrock (unless it is painted with a vapor barrier sealer-paint or        
    backed with a vapor-retarding polyethylene film).                           
                                                                                
    Air barriers are used to address the first four problems while a            
vapor retarder is normally installed to deal with vapor diffusion.              
                                                                                
    The tendency of warm air to rise and flow through openings in the           
ceiling is called the stack effect because it is similar to the                 
operation of a chimney stack.                                                   
                                                                                
                                                                                
%G CEIL2A.PCX; The stack effect in a house.                                     
                                                                                
Figure 2 shows how warm humidified air rises to the uppermost ceiling           
and flows through openings (called exfiltration), while cool outside air        
infiltrates through various openings or air intakes in the lower part of        
the house.                                                                      
                                                                                
The Importance of Fresh Air Intake                                              
                                                                                
    Although it is important for the ceiling and upper portions of a            
house to be airtight, the lower portion of the house (usually the               
basement) must have one or more intake points for fresh air.  The intake        
points allow fresh air to flow into the house when exhaust fans are             
turned on to remove odors and excess humidity.  Ventilation fans provide        
airflow as needed when used with a timer, humidity control, or manual           
switch control.  Separate fresh air intakes are also needed for air             
supply to fuel-burning equipment or atmospheric-type combustion                 
appliances.                                                                     
                                                                                
    As previously mentioned, a house has many openings in the ceiling.          
These openings, combined with the stack effect, result in an upward flow        
of air that can cause problems.  One effect of the upward airflow is            
development of a negative pressure zone in the lower portions of the            
house (see Figure 3).                                                           
                                                                                
                                                                                
%G CEIL3A.PCX; Upward Air Flow.                                                 
                                                                                
In addition, if the lower levels of the house are leaky, the upward draw        
at the top causes cold air to infiltrate into the lower level                   
continuously.  (Outside air pressure is considered neutral, or zero.)           
Lower portions of the enclosed space tend to have slightly lower                
pressure than outdoors, which causes cold drafts to enter.  Low or              
negative interior pressure can interfere with proper venting of                 
furnaces, water heaters, fireplaces, or woodstoves.                             
                                                                                
    A house that is tightly constructed, with a vapor-retarder and air-         
barrier system in the walls and ceiling, will tend to be free of the            
problems already discussed.  However, other problems may show up if             
fresh air intakes are not provided.  In tight houses, fresh air intakes         
are needed in areas where fuel-burning appliances are located.  Some            
appliances may allow intakes to be coupled directly to them.  In houses         
equipped with exhaust fans, adequate intake vents are needed to replace         
air that is exhausted.  Ideally, a supply air fan is used to provide the        
correct quantity of makeup air.                                                 
                                                                                
What is a Vapor Retarder?                                                       
                                                                                
    Materials that resist the passage of water vapor are called vapor-          
retarder materials.  Polyethylene film, paint-on vapor-barrier sealers,         
and aluminum foil are vapor retarders.  The effectiveness of a vapor-           
retarder material is measured by its perm (permeance) rating.  Low perm         
means low passage of water vapor.  Plastic films, foils, sealers, or            
paints with a perm rating of less than 1.0 are generally considered             
adequate as vapor retarders.  A combination of materials may be used in         
the vapor-retarder system.  The vapor retarder must be on the interior          
(warm side) of the ceiling structure so that it will stay warm enough to        
prevent condensation from occurring on the retarder itself.                     
                                                                                
An Air-Barrier System                                                           
                                                                                
    Vapor retarders are not to be confused with air barriers.  A well-          
constructed vapor-retarder system, using high-quality materials that are        
uniform in thickness and resistant to degradation in use, can serve as          
an air barrier.  However, construction practices currently in use in the        
United States generally lack the quality control required for vapor             
retarders to also serve as air barriers.                                        
                                                                                
    Why the need for an air-barrier system?  Considerably more moisture         
is lost in a home through convection than through diffusion.  Convection        
losses occur when water vapor escapes the house through open windows,           
the chimney, cracks, and other air leaks (TenWolde and Suleski 1984).           
Air-barrier systems are designed to reduce air leaks through the                
building envelope.  There are several materials that may be used as an          
air barrier if they meet the following requirements (Lstiburek 1987b):          
                                                                                
 ** They are continuous.                                                        
                                                                                
 ** They are sufficiently impermeable to air (0.1 liters of air or less         
    passing through the system per second per square meter at 75                
    Pascals).                                                                   
                                                                                
 ** They withstand the air pressure loads on them--including the local          
    minimum wind design loads, the influence of mechanical systems, and         
    stack effects.                                                              
                                                                                
 ** They are stiff enough to maintain pressure equalization behind              
    exterior cladding.                                                          
                                                                                
 ** They are durable and easy to maintain over the service life of the          
    building.                                                                   
                                                                                
    Although polyethylene film has been promoted as an air barrier (an          
generally meets the first two requirements of continuity and                    
impermeability), most poly materials used in this country do not meet           
the last three requirements.  Gypsum board, stress-skin panels, and             
sprayed-in-place foams do meet all five requirements (Lstiburek 1987b).         
                                                                                
    It is important to note that the installation of an air-barrier             
system within a house creates a very tight structure.  Consequently,            
controlled ventilation systems must also be installed in conjunction            
with air-barrier systems.  Also, buildings are especially leaky at top          
plates of exterior walls.  Therefore, any strategy used to construct an         
airtight air barrier must not leave the barrier discontinuous in this           
area.                                                                           
                                                                                
Bypasses or Hidden Air Leak Passages                                            
                                                                                
    Indirect or hidden paths and openings where warm humidified air can         
leak through the structure are called bypasses.  Examples of bypasses ar        
wire and pipe holes through the tops of walls, drop ceilings, soffits,          
recessed lights, gaps in the tops of partition walls, and gaps around           
chimneys and attic access doors (see Figures 4 and 5).                          
                                                                                
                                                                                
%G CEIL4A.PCX; Bypasses along wire and pipe holes.                              
                                                                                
%G CEIL5A.PCX; Switch Plates and wire in Walls.                                 
                                                                                
Evidence of bypasses in older houses may include water stains on the            
attic floor, ceiling joists, or roof boards (from condensation) or dust         
buildup in the insulation (from house air filtering through).  Special          
inspectors can scan the attic with an infrared viewer to find the               
location of bypasses (look under "Building Inspection Services" in the          
Yellow Pages or call your community energy office or county extension           
office for more information).                                                   
                                                                                
    Flow of warm air from any bypasses (and other holes) warms the              
underside of the roof and can melt snow during subfreezing weather.  The        
melted snow runs down the roof shingles and refreezes at the eaves,             
forming an ice dam (see Figure 6).                                              
                                                                                
                                                                                
%G CEIL6A.PCX; Ice Dams in attic walls.                                         
                                                                                
The ice buildup at the eaves can then cause water to collect on the             
roof and seep through the shingles, resulting in a wet roof deck and wet        
attic insulation, soffits, ceilings and walls, and wall insulation.             
Repeated episodes can eventually lead to rot in the roof deck or walls.         
                                                                                
Creating the Air Barrier and the Vapor Retarder                                 
                                                                                
    Air barriers are designed to control air leakage and vapor                  
retarders are designed to control vapor diffusion.                              
                                                                                
    Polyethylene ("poly") film is a commonly used vapor-retarder                
material that does a good job if it is properly installed.  Figures 7           
and 8 illustrate methods to install a polyethylene vapor retarder and to        
seal connections and openings so that the air barrier and vapor retarder        
become one system.                                                              
                                                                                
%G CEIL7A.PCX; Techniques for effective vapor retarders.                        
                                                                                
%G CEIL8A.PCX; Air barrier system.                                              
                                                                                
                                                                                
Materials other than polyethylene are also available, including rubber          
gaskets and drywall with special vapor-seal paint or foil backing.              
Using the Airtight Drywall Approach, gaskets and sheetrock may be               
combined to create an effective air-barrier system (see Figure 9).              
                                                                                
                                                                                
%G CEIL9A.PCX; Using the Airtight Drywall Approach                              
                                                                                
                                                                                
    During construction, ceiling insulation should be installed                 
immediately if the weather is cold.  The situation where a poly vapor           
retarder and sheetrock are installed in cold weather, but installation          
of ceiling insulation is delayed, can lead to problems.  Without                
insulation, water vapor can condense on the poly vapor barrier and drip         
on the sheetrock.  In existing houses, vapor barrier sealer-paint can be        
used on the plaster or sheetrock, together with sealing of openings.  A         
paint-on vapor barrier usually requires two coats to achieve full               
coverage with a perm rating of 1.0 or less.                                     
                                                                                
Proper Attic or Ceiling Insulation                                              
                                                                                
    Ceiling insulation must be adequate in all locations to prevent             
condensation on interior surfaces.  High-heel roof trusses are designed         
to allow sufficient space in the attic to install full-depth ceiling            
insulation to the edge of the ceiling (see Figure 10).                          
                                                                                
%G CEIL10A.PCX; High-heel roof trusses.                                         
                                                                                
Extra insulation for the ceilings over high-humidity areas (such as             
bathrooms) may be helpful in maintaining warmer ceiling surfaces and            
thus preventing condensation on interior surfaces when they are exposed         
to steamy humid air.                                                            
                                                                                
For Further Information                                                         
                                                                                
    For information on the principles of humidity, moisture movement,           
and condensation, see Humidity and Condensation Control in Cold Climate         
Housing (CD-FO-3567).  Your county extension office has a Home Energy           
Handbook, which lists further reading materials.                                
                                                                                
Summary                                                                         
                                                                                
Mechanical ventilation systems are needed in airtight houses to reduce          
humidity levels and the risk of condensation-related damage.  Tightly           
constructed houses without suitable ventilation systems may also have           
poor indoor air quality.  Adequate insulation must be installed to keep         
inside surfaces warm enough to prevent surface condensation (of                 
particular importance in corners and bathrooms).  Finally, the building         
and wall system itself must be "forgiving" over a wide range of                 
conditions.  It must allow moisture in building materials (i.e., framing        
lumber) and concealed condensation to rapidly dry to the outdoors.              
                                                                                
Endnotes                                                                        
                                                                                
                                                                                
References                                                                      
                                                                                
Canada Mortgage and Housing Corporation.  1987.  Moisture Problems.             
    Ottawa, Ontario, Canada.                                                    
                                                                                
Iowa Department of Natural Resources.  1987.  A Builder's Guide to Iowa's       
    Ideal Homes.  Des Moines, Iowa:  Energy Bureau, Iowa DNR.                   
                                                                                
Latta, J.K.  1985 (March).  The Principles and Dilemmas of Designing            
    Durable Housing Envelopes for the North.  Ottawa, Canada:  National         
    Research Council of Canada, Division of Building Research.                  
                                                                                
Lstiburek, Joseph W.  1987a (March).  Applied Building Science.                 
    Downsview, Ontario, Canada:  Building Engineering Corporation.              
                                                                                
Lstiburek, Joseph W.  1987b.  "How to Control Moisture in Houses."              
    Custom Builder.  December: 9-14.                                            
                                                                                
National Research Council of Canada, Institute for Research                     
    Construction.  1985.  The Difference Between a Vapor Barrier and an         
    Air Barrier.  BPN 54.  Ottawa, Ontario, Canada.                             
                                                                                
Peterson, Roger A. and Lewis T. Hendricks.  1988.  A Systems Approach to        
    Cold Climate Housing.  Cold Climate Housing Information Center.  CD-        
    FO-3566.  Minnesota Extension Service, University of Minnesota, St.         
    Paul, Minnesota.                                                            
                                                                                
TenWolde, Anton and Jane Charlton Suleski.  1984.  "Controlling Moisture        
    in Houses."  Solar Age.  January: 34-37.                                    
                                                                                
                                                                                
........ National CD-ROM Sampler . \docs\nc\cold\text\ceiling.txt ........     
                                                                                

    
                                  [Image]

                             Building Hot Roofs

by Gene Leger

Attic and roof ventilation is one of the most hotly debated topics in
residential construction. There are no fewer than seven schools of thought
on the subject:

  1.  Attic ventilation is necessary.
  2.  Attic ventilation is not necessary.
  3.  Attics should be power-ventilated.
  4. Attics need only intermittent ventilation.
  5.  Ventilation of superinsulated attics (R-40 or more) is dangerous and
     does not work.
  6.  Insulation, light-colored shingles and natural ventilation make power
     vents unnecessary.
  7.  In hot/humid, and hot/arid regions, thermal and reflective
     insulations, combined with solid white or light-colored roofs, are the
     most effective means of reducing attic roof temperatures.

Try to get a dozen builders to agree on one of the above...unlikely! Now
try to get a whole industry to agree...impossible!

Why Ventilate?

Do we really need it? Traditionally, attic and roof ventilation were
recommended as a means of removing moisture that escapes from the living
space into the attic or roof cavity, cooling the outer roof surface to
prevent snow damage and ice-dam formation, reducing attic temperature by
structural cooling, reducing the home's cooling load and prolonging the
life of the roof. (Roof cavities are formed when cathedral ceilings are
built. The "cavity" is the space between the dry wall and the roof
sheathing.)

Obviously there is disagreement on the need to ventilate attics and roofs.
While most manufacturers agree ventilation is necessary, they generally
disagree on how it should be accomplished. Some believe in ridge vents, the
most common form of ventilation in northern New England, others don't.
There have been claims and counterclaims about net free venting area
(NFVA), whether external baffles are necessary and if ridge vents and
soffit vents must be balanced.

Attic Ventilation and the Building Codes

Regardless of the inconsistencies found in building codes, on one thing
they all agree...even to the exact wording: "Attics must be ventilated."
The code requirements originated with the Federal Housing Administration
(FHA) in 1942 and were incorporated into FHA's Minimum Property Standards
(MPS). The first appearance of the MPS in the model building codes was in
the 1950 BOCA Basic Building Code.

These codes and the CABO, The One and Two Family Dwelling Code, require the
ventilation of enclosed attic and rafter space formed when ceilings are
applied directly to the underside of the roof rafters. Section R-707 of the
CABO code allows the building official to determine if atmospheric or
climatic conditions necessitate attic ventilation.

Is Attic Ventilation Climate Specific?

The closest to a universal form of attic ventilation is the gable-end
louvered vent, ranging in size from very large triangle vents to a single
slit. According to one investigator, "The aesthetic appeal of simple
louvers has been a major factor in their continued and popular use."

Unfortunately, they have limited control of rain and snow penetration when
they are sized for summer ventilation. More expensive, more complicated
louvers are equally limited in stopping rain and snow penetration.

Canadian building scientist Y.E. Forgues, in his paper, "The Ventilation of
Insulated Roofs" warns, "Gable vents have a series of blades sloped at 45
degrees. If not properly designed, they may allow rain or snow to enter the
roof space... In regions such as the Prairies, which are subject to fine,
wind-driven snow, gable vents may have to be closed in winter to prevent
snow from accumulating in attics."

Many New Englanders, in addtition to those living in the American Prairies,
found their attics full of snow after a northeaster because one of the
gable-end vents faced north. American Vietnam veterans tell of the sand in
the barrack attic brought in through the gable-end vents. Hundreds if not
thousands of houses in Oklahoma have sand-covered attic floor insulation
brought in through turbine vents.

Houses equipped with ridge vents and soffit drip-edge vents (Fig.1) have
also suffered from accumulation of snow in the attic. Reports from Toledo,
Ohio, Buffalo, New York, Minnesota and other areas tell of snow being blown
through the drip-edge vent up to eight feet into the attic. Only a
drip-edge vent with an external baffle will stop the rain and snow
penetration. Until recently a drip-edge vent was unobtainable. However, the
Combo Vent Company now produces such a vent. (Figure 2). Unfortunately,
there is no performance data available at this time.

When all is considered, a number of experts feel attic ventilation is
contra-indicated in residential construction. At the March, 1994,
Affordable Comfort Conference, Don Fulgar, of the Canada Mortage and
Housing Corporation (CMHC) said that his research shows that attic
ventilation is not necessary to control moisture and may indeed make the
moisture problem worse. William Brown, of the Canadian National Research
Council, cautions that ventilating attic moisture not only will not cure
the problem, but may make it worse.

American building scientists such as Bill Rose, of the University of
Illinois, and Anton TenWolde, of the U.S. Forest Products Laboratory, also
argue that unvented cathedral ceilings provide better performance and
better moisture protection than ventilated cathedral ceilings. TenWolde's
research suggests that very often ridge and soffit vents cannot provide
enough outdoor ventilation to maintain dry conditions in the roof.
Moreover, building scientists in hot arid climates (We sometimes forget
that of the climate zones in the U. S., one is hot and arid and the other
is hot

and humid.) say that because solar radiation factors in roof heating,
thermal and reflective insulations are the most effective ways to reduce
the heat in the interior living spaces. Natural ventilation, they claim, is
both ineffective and unnecessary.

With such strong protestation against it, are we to assume that attic
ventilation is not necessary in all situations? If the answer is yes, then
this is a major departure from what we have been told by industry experts
for many years.

Hot Roofs

Let us be clear for a moment about the definition of a "hot roof." A hot
roof is an unvented cathedral ceiling. (We will deal with unvented attic
spaces - and how to build them - in future issues.) Assuming you buy the
premise that cathedral ceilings need not be ventilated, there are a few
things you must consider.

We know that building codes mandate cold (ventilated) roofs. But the codes
also permit alternative construction methods and materials. The 1993 BOCA
National Building Code, Section 106.4 Alternative Materials and Equipment
says:

The provisions of this code are not intended to prevent the installation of
any material or to prohibit any method of construction not specifically
prescribed by this code, provided that any such alternative has been
approved. An alternative material or method of construction shall be
approved when the code official finds that the proposed design is
satisfactory and complies with the intent of the provisions of the code,
and that the material, method or work offered is, for the purpose intended,
at least the equivalent of that prescribed in this code in quality,
strength, effectiveness, fireresistance, durability and safety.

Furthermore, Section 105.6, Rule-making Authority: allows the building
official to"...adopt and promulgate rules and regulations to interpret and
implement the provisions of this code to secure the intent thereof..."
Clearly the building official has the authority to permit hot roofs.

CAUTION: The fastest way to get a STOP WORK ORDER is to construct a hot
roof without telling the building official. He has the authority to issue
or deny a permit. His decisions are, of course, appealable. You will need
to convince him that you have a design for air-tight drywall that will
prevent moisture from escaping from the living area into the attic or roof
cavity. Be sure he understands you intend to eliminate the roof
ventilation. It is better to be delayed at review time than have your job
shut down mid-way through construction.

Types of Hot Roofs

All hot roofs will have warmer roof surfaces than ventilated or "cold"
roofs. (In a cold roof, the outside surface of the roof is cold because it
is uncoupled, or isolated, from the insulation by the air space between the
two. The flow of air above the insulation from the soffit vent to the ridge
vent removes moisture and warm air from that space.)

Hot roofs take a number of forms:

A) The rafters are stuffed full with fiberglass insulation;

B) Polyurethane foam insulation is sprayed on the underside of the roof
sheathing and the remaining cavity spaces are filled with fiberglass batts;

C) Rigid foam board sheathing is installed on top of the exterior roof
sheathing with the shingles installed over the foam board. The rafter
cavities are filled with fiberglass insulation. (Figure 3)

Type A is the simplest and cheapest way to build a hot roof but it is the
least forgiving and most prone to failure. This type is based on the
assumption (too often a poor assumption) that the vapor diffusion retarder
(formerly known as vapor barrier or air vapor barrier) and the air retarder
have near zero permeability, are constructed of durable, long lasting
materials and, of critical importance, are installed with meticulous care.
A reinforced plastic sheathing, such as Tu-Tuf� works well. Any moisture
that gets through a less-than-perfect vapor diffusion retarder will
condense on the cool roof sheathing. Because it is unable to escape, the
moisture can damage the ceiling and eventually rot the roof. Think twice
about recessed lighting fixtures and ceiling fans. They spell LAWSUIT!

Spraying polyurethane foam insulation to the underside of the roof
sheathing provides an airtight, watertight seal. Here again, durable
quality materials and flawless installation of the vapor and air retarders
are crucial. Type B is more forgiving because of the polyurethane
insulation. It tempers the sheathing by keeping it at a warmer temperature.
The warmer temperature lessens the chance of moisture condensation should
moisture-laden air penetrate the retarders. Types B and C are similar to an
exterior wall (see the article and illustration by John Reynolds, House
Magazine, January, 1994, page 16.)

There have been few moisture condensation problems with this type of
construction. I have seen frost build up between foam board sheathing and
the fiberglass insulation. Air leaked through openings in the air retarder,
sheetrock and VDR, and between the joints of the foam board. Rigid foam
board over the studs does not necessarily provide an airtight exterior
wall.

Ice Dams

Ice dams result from the combination of too little insulation and
inadequate attic or roof ventilation. Escaping warm air easily raises the
sheathing temperature to above freezing, even when it is below freezing
outdoors. However, heavily insulated attics (R-40 or R-50) keep the roof
sheathing temperature close to the outdoor temperature. Snow should not
melt anywhere on this surface.

Unfortunately, in areas with heavy snowfall and little wind, snow will
accumulate on a roof. Fresh snow has an R-value of about R-1 per inch. As
the snow piles up, the R-value increases, less heat escapes, and the roof
surface temperature increases. Soon the sheathing temperature is above
freezing and the possibility of an ice dam becomes very real. However, this
depends on the R-value of the roof, the depth of the snow and the exterior
temperature. The higher the R-value of the roof, the greater the amount of
snow it can handle before the sheathing temperature rises above freezing
and the melting starts. (Assume an outdoor temperature of 20 degrees F and
an R-20 roof. The sheathing temperature will rise above freezing with as
little as six inches of snow. An R-60 roof will accomodate sixteen inches
of snow before the sheathing temperature rises above freezing and the
melting starts.)

CAUTION: A house with a hot roof in the snow belt could suffer from ice
dams if eight inches or more of accumulated snow remains on the roof for a
month or more. A hot roof in an area of high winds should be free from the
worry of ice dams. The winds prevent the buildup of insulating snow layers.

The Hot Roof to Avoid

There is a cold roof that, through ignorance, carelessness and lack of
planning turns into a hot roof with disastrous consequences. This is the
lethal - for the roof - combination of ten inches of R-30 fiberglass in a
2x10 rafter with, or without, a vent chute. There are a number of problems
with this combination. First, how do you get ten inches of fiberglass
insulation into a 9 1/4-inch cavity? Second, with the cavity full of
insulation, how do you ventilate it?

Tens of thousands of cathedral ceilings were built after World War II with
this combination. Some well-meaning, but misguided builders added the vent
chute. The cavity depth in the 2x10 roof is now reduced to 7 1/2 inches.
The insulation installers, working for a penny per square foot and paid to
insulate and not think, simply shoved the ten inches of insulation all the
way home into the cavity. Trapped moisture, unable to exit, damaged the
ceilings, rotted the roofs and resulted in millions of dollars in damage
and lawsuits.

Some experts argue that the above scenario could not happen if high-density
eight inch fiberglass was used. Yet experience shows that the eight inch
batt can loft or fluff up to ten inches. Thus, the 2x10, eight-inch batt
combination can also be lethal. The vent chute here is a must. Otherwise,
use 2x12 rafters. If you frame at 24 inches on-center you will actually
save money over 2x10's at 16 inches on-center. Cost is further reduced
because vent chutes are no longer necessary.

ARMA and Hot Roofs

You have decided to do a hot roof and you are committed to doing it
correctly, even to hiring an "expert" to show you how to properly seal the
retarders. Are you out of the woods? No! The Asphalt Roofing Manufacturers
Association (ARMA) will void the shingle warranty on an unvented roof.
Unfortunately, there is little evidence - ARMA provides none in its
Residential Asphalt Roofing Manual - for or against lack of attic or roof
ventilation affecting shingle life. Two studies have been conducted, but
neither study has been released to date.

ARMA's strongest argument may be in its warning against installing shingles
directly over insulated decks or rigid foam board insulation. This would be
the case when these insulations are installed on the exterior of the roof
deck. (For more information, see ARMA's technical bulletin, "Direct
Application of Asphalt Shingles Over Insulation-or- Insulated Decks."

Gene Leger built one of the first double-wall, super-insulated homes in
1977. He has worked as a building code enforcement officer for the town of
Merrimack, NH, has written numerous articles and most recently has revised
the book Complete Building Construction for the Macmillan Company.

                        To be a sponsor of this site

      [ House Magazine Home Page] [House Magazine Table of Contents]

                  [Home Page] [Construction Publications]

   [Construction Product and Service Directory] [Construction Resources]

         For comments or information contact us at: House Magazine.

   Copyright 1995 by Patrick Gass and Company, Inc. All Rights Reserved.

I'm finding another advantage of continuous soffit venting as I'm
on my roof clearing ice dams.

It gives at least SOME of the water that's leaking into your roof
a place to drain out.

Clue:  If you've got those cute little icicles hanging out of your 
soffit vents, be glad you're losing SOME of the water, but be warned
you've got more up higher inside.
And if you've got those house-hugger icicles forming on your siding with no
obvious source of drippage, then it's also too late - that's the water that's
making it back out of the wall.

Yuk...

- tom]

    Can anyone recommend a company in the Maynard area that can clear the
    roof and chip off the ice dams -- there's no way I'm going up on my
    roof.
    
    I was thinking of calling Locke's Window and Gutter Cleaning (I think
    they're in Concord).  Any comments plus or minus on them or anyone else
    is much appreciated.
    
    ****andrea****
    

In today's Globe, handyman Peter Hotten says not-to-worry
about roofs collapsing due to snow load, since houses these
days are built to take 2' of snow...

Problem is, there's now > 3' of snow and 2" of ice on my
roof, and tomorrow's storm promises to bring lots more of
both.

The house is a 23 y.o. (gambrel in front)/(flat face in
back). So the pitch in back (facing north, gets little/no
sun) is fairly shallow and has the dams.

Are my fears of collapse warranted?  Do I need to get out
my ropes/harness and clear the roof?  Or is everything fine?

Tom 

    my friend was just telling me last night how he made
    his snow rake from a piece of conduit and an old pine
    board couple that with Steves $100 idea of the rubber sguegee
    and walla roof rake for cheap and no waiting.  FYI
    
    
    		Dean

    Well, I hadn't been worried about the 2+ feet of snow on the roof of my
    split, but what got my attention last night was listening to both Bruce
    & Dickie (Boston-area weather wizards) warn about how the Fri/Sat storm
    may be a combo of heavy, wet snow and some sleet and rain. They both
    made a point about how this type of moisture can increase the weight of
    the existing snowpack by a factor of 5! They also suggested that people
    take advantage of today's milder weather to clean off as much snow as
    safely possible from shallow-pitch or flat roofs, as well as decks and
    pool covers. (They also talked about clearing a 3 or 4 ft. "moat"
    around the foundation, to alleviate waterpressure, but that's a topic
    for another note.) 
    
    Since I'm fighting ice dams on my roof, and can't find a roof rake
    anywhere within 30 miles of my home, this advice was the final step in
    convincing me to get up on the roof and start shoveling. Was able to 
    remove all snow for about 7 or 8 ft back from each gutter...if time
    and conditions allow tonight, I might attempt to tackle some more of
    the roof, but I've got a 12x24'deck buried under 4+ feet that needs to
    be done first.
    
    Needless panicking? Maybe...but since I needed to clear away for the
    ice dams, it was definitely time well spent. (On the other hand, I haven't 
    noticed anyone else shoveling off their roofs...:^)
    

We have been mystified at the cause of our ice dams during this winter, and the
winter of 93-94.  Our house was built in 1991, and we went out of our way to
provide insulation, ventilation and that rubber membrane to prevent water and
ice damage.  Yesterday, my husband went up on the roof to shovel off the ridge
vent.  There had been over two feet of snow up there.  He said there were about
6 vents along the whole roof, but when he started shoveling, the bottom six
inches was all slushy.  So in this case, the ridge vent was actually
contributing to the ice dam problem.

We now own a snow rake, which is easy to use after each snow fall.  It's not so
easy to shovel the ridge vent every few days.  I wish there were some easier way
to clear the ridge vent after heavy snow storms.  But until there is, we are
stuck with the system we designed.

Elaine

re .369:

Anyone with a code table know what the dead weight rating (lb/ft�) for a flat
roof consisting of 2x6, 16" center, 10' span between supports (and by 2x6
they're really 2" by 6") and 1"xrandom decking?

It (a barn) has stood for 50 years, but...

    Just moved back to New England into a 23 year old house and
    I have ice dams.  (Sounds like an AA confession).  

	Symptoms:  *  Water dripping into 2nd floor bathroom around
			ceiling FHA vent and through toggle bolt
			hole for track lighting.
		   *  Bubbling of ceiling paint in same bathroom
		   
	Attic:	   *  Installed R25 Miraflex in early December on top 
			of existing fiberglass bats between joists
			(will check to make sure that I did not block
			soffit vents)

	Roof:	   *  Went on top of my roof (1st time this season)
			and shoveled off all snow 5 ft from edge of 
			gutter
		   *  Gutters are completely choked with ice as a
			rock solid block
		   *  Ice sheets dam up and extend 2-4 feet onto the
			roof.  Can see wetness and melting pooling up
			in places.
		   *  Roof is 2.5 stories off the ground.
		   *  Chipping at the ice is slow going and dangerous
			(22 foot fall)

QUESTIONS:  1)  Am I correct in believing that I need to get these
		dams off ASAP?

	    2)  What sort of damage have I done?  Will a scrape and
		new coat of ceiling paint do the trick?

Phil

    >
    > In today's Globe, handyman Peter Hotten says not-to-worry
    > about roofs collapsing due to snow load, since houses these
    > days are built to take 2' of snow...
    >
    > Problem is, there's now > 3' of snow and 2" of ice on my
    > roof, and tomorrow's storm promises to bring lots more of
    > both.
    
    No. What he said was "If you're worried the mass of snow on your roof
    will cause it to cave in, don't be. The vast majority of roofs are 
    built to take heavier loads than 2 feet of snow."
    Notice he said "heavier than 2 feet", he did not say that 2 feet
    was the maximum load. If so, we'd all be in big trouble.
    
    No let's just hope Peter knows what the heck he's talking about! :-)
    How come your roof has 2" of ice on it? You mean on top of the snow
    or under it?
    

I made mine by attaching a 1x4 to the end of my pool vacuum handle.

/C

I heard a new (to me) theory today -- that gable vents are a detriment to the
soffit/ridge ventilation system.  Even though gable vents may help 
in the summer for hot air escape, they interfere with the flow from
soffit to ridge, which in turn reduces soffit intake which in turn
leads to .... blah blah blah ...which causes ice dams.

This person suggested covering the gable vents. Anyone heard of this?   
done it?

    
    When I went to home depot to buy one. They had a delivery coming
    in from ohio, but it was delayed because of the weather. So they were
    instead making them by bending a long piece of the metal electrical
    conduit ( emt? )at one end and attaching a standard shovel to the end
    of the conduit.
    
      I thought about it and decided like .376 that I have two pool poles
    that I could use to make one. So I bought a new plastic push shovel
    ( de-commissioned my old one at home, and a 90 degree plastic conduit
    elbow. Cut all but around 3-4" of the shovel handle off. Attached the
    90 degree elbow to that with a wood screw. Then took my vacume pool pole
    and inserted it in the other end of the elbow with a couple screws, and it
    works like a charm.
    
    Total cost $11.00 ( new shovel to replace old one )
                 1.50 ( plastic conduit 90 elbow )
                12.50 ( roof rake/shovel cost )

	When not blocked by snow or ice, soffit and ridge vents
are supposed to work together to keep the roof underside cold,
so that the snow won't melt and run off and freeze on the colder
overhang, causing an ice dam.  
	Now, add 2 feet of snow into the picture.  The ridge vent
is covered and inoperative - therefore so are your soffit vents.
Heat leaks warm the attic, snow start to melt, trouble begins...
In this situation gable vents might help, if they act as the exhaust
and the soffits as the inlet. (I'm assuming a traditional attic here -
insulation between the ceiling below and the attic floor, nothing above
but gable roof, soffit, ridge, and gable vents.
	Perhaps the thing to do is keep the gable vents covered until
the ridge freezes?

    	Anyone know where the "ice damming" string is? There's no keyword
    (gutters don't work) and I can't find it. Found one reference to note
    736, but the content must have been moved.....
    
    	P.S. I had at least 3 quarts of water pour thru my bedroom ceiling
    last night....
    
    	Thanks!
    	Dave

> Anyone know where the "ice damming" string is?

	Well this is supposed to be the ice dam topic, however it appears
	the notesfile corruption problem has resulted in the roof ventilation
	topic flowing over into this topic .....

:-)

And when you open the conference the message says to read note 6.3.

    OK...I fought the battle valiantly, but lost it anyhow :^(
    
    Shoeveled most of the roof last Wednesday night, but Friday's heavy,
    wet snow coupled with warmer temps resulted in 7 or 8 places (at last 
    count) where wataer has made it's way in and stained the ceilings. I
    went into the attic to try to find the particular source(s), but no
    apparent drippage from the rafters or from the roof boards. Pulled back
    some insulation as well, but again couldn't find anything obvious.
    
    I went back up on the roof Saturday morning and cleared off the new
    snow/slush, and also disconected the downspouts from the gutter to 
    allow clearer drainage, and with the balmy temps (high 30's :^) over 
    the weekend, the water seems to be draining pretty well at the moment.
    But what do I do now to repair the ceiling damage? Also, what damage
    might have occurred inside the walls? Will the insulation dry out as
    temps increase (perhaps in spring/summer?) In the meantime, what can I
    do/what should I look for?
    
    Again, thanks for any useful info.

Let it dry thorougly and use a shellac-based primer (BIN, Kilz, etc.) on the
stains, then repaint.  You can even get a special spray can of primer that
is especially designed for ceilings - it sprays up and is slightly colored to
match old white paint.  I have a can but haven't used it yet.

There's not much you can do for the walls - they will dry out eventually.

You may have the problem I do - ice backing up into the soffit then melting.
You won't see anything coming from the roof at all.

I've been through this twice so far.  This summer I will improve the attic
insulation and ventilation (I found that the soffit vents are blocked by
insulation) and replace the gutter with "Englert Leaf-Guard" that has an 
integral leaf shield that will also prevent ice from backing up into the
soffit.

You can also install heating wires on the roof to keep the edge clear, or,
if you can reach it, use a roof rake to remove at least three feet of snow
back from the edge after each snowfall.

				Steve

followup to .369:

On Thursday, I went up on the roof and cleared the section of 
roof with the most snow (~ 3.5').  Of course, I woke up Friday
to a leaking dining room, under the section of house I did _not_
clear.  

The problem:  the crease between the two pitches of our gambrel
roof could not sustain the weight of the snow and ice over it.
The ice dam was about 3" high and 8" wide, and as long as the 
length of the house.  I counted two places this buckling had
caused leaks. The buckling was only an inch or so, tops.
Due to time constraints, I cleared off the snow and dams in only
these two places.  I then used a can of "Great Stuff" foam in 
the exposed cracks (was this a bad idea?), and took off, with 
trepidation, for the weekend on our planned ski trip.  

Got home last night to a dry dining room with no additional drips,
so the foam stuff seems to have stemmed the tide, temporarily at
least. I'll be finishing up the rest of the house this afternoon.

re: .375:

>    >
>    > In today's Globe, handyman Peter Hotten says not-to-worry
>    > about roofs collapsing due to snow load, since houses these
>    > days are built to take 2' of snow...
>    >
>    > Problem is, there's now > 3' of snow and 2" of ice on my
>    > roof, and tomorrow's storm promises to bring lots more of
>    > both.
    
>    No. What he said was "If you're worried the mass of snow on your roof
>    will cause it to cave in, don't be. The vast majority of roofs are 
>    built to take heavier loads than 2 feet of snow."
>    Notice he said "heavier than 2 feet", he did not say that 2 feet
>    was the maximum load. If so, we'd all be in big trouble.
>    No let's just hope Peter knows what the heck he's talking about! :-)

You raise a valid distinction.  However, the 3.5 to 4 feet of snow on most
Northern Mass. roofs is almost twice the minimum capacity he cites.  I still
worry.  As alluded to previously, there's already been some buckling...

>    How come your roof has 2" of ice on it? You mean on top of the snow
>    or under it?

No, I refer to the ice dams below the snow packs.

re: stains

though it doesn't always work, I've had some success just putting gold ol'
bleach on them.  give it a shot before you go to all the pain of painting...

-mark

    We used a 50-50 mixture of bleach and water to remove water stains on 
    our plaster ceiling.  It too several applications but you can't see the
    stains any longer.
    
    							John

    
    Re: a few back about cost of ice & water shield $$$
    
    I'm using two types currently, both are 3' wide and cost about
    1$/ft.  GAF Ice & Water shield (found at HD) comes in 50ft rolls
    and costs about $55/roll.  Bitathane(sp?) can be found at PJ Currier
    comes in 75ft rolls and is about $80/roll.  The GAF is thicker and
    has a less agressive first time stick.  Its somewhat more difficult
    to work with, but I'm not using it on the roof, but rather for
    underflashing around rim boards for decks (there is standard metal
    top flashing too).  The Bitathane is being used on the roof, two 
    courses w/6" overlap - this is partly because there is a large soffit
    overhang (1'6").  It has a more aggressive 1st time stick, and is very
    flexible even in cold weather.
    
    In terms of cost for the ice shield and total cost
    of roofing materials, its added about 15% more to the roof - but I've
    also used the material at all valleys, roof edges, and knee walls which
    is significantly more material than all the roof edges.  If I used it 
    just on the edges, I'd have about an additional 6% more in material
    costs.
    

    re:GAF Ice & Water shield
    
    	Perhaps it's a seasonal thing, but I thought that the cost was closer
    to $65/roll last I checked. Two courses on my roof would add $260 to
    the materials (44' long house w/dormers). This is non-trivial.
    
    	One of the things that I was going to look into is the corregated
    metal roofing. I believe this comes in 8'/10'/12' long sections. I saw
    a roof done on a house in Vermont with a brighter sort of barn board
    red colored roof, and thought it actually looked pretty good. I also
    saw one in a darker green that looked nice too.
    
    	It added more color to the house than what you'd typically see. It
    should eliminate any possibility of leaks from ice dams, and could
    easily be installed over existing shingles, lending itself to a DIY as
    time permits sort of project. Installation would be *much* faster and
    easier than shingles. 
    
    	It should also allow air to flow up the corregated channels to provide 
    for another level of ventilation. This helps to alleviate a design
    problem on my Gamrel roof, as the gap between the two different roof
    angles doesn't appear wide enough to provide for adequate ventilation.
    
    	From what I remember, the roofing is guarenteed for 15 years, which
    is a minus over shingles. Some would say looks are a down side, but
    that's a matter of personal preference. Overall, the pluses outway the
    minuses (for me), at least enough to look into it. Any other thoughts ?
    
    	Ray
    

    
    I was HD end of last week and the price was in the $52-$56 range, don't
    remember specifically.  Whatever, price per foot still is buck a foot
    range so it can get expensive.  But (re)roofing in general gets kinda
    expensive.
    
    Corrigate metal roofing.  We did a cabin up north with this once.  At
    the time it didn't come in fancy colors, in fact you couldn't paint it
    and expect it to last because of the high expansion/contractions
    problems vis-a-vis paint.  Since then I've seen that the manufacturers 
    (at first) offered a specific DIY paint and now offer a pre-applied
    (baked on?) finish.  Some downsides in working with this stuff.  
    
    1) its noisy when it rains... real noisy.
    2) its noisy when its hot and nite comes (ping, pang, POW) as the
       metal cools
    3) it was difficult to seal well at the ridge, might have been us -
       although we used the right parts
    4) it did leak occasionally along the vertical seams (if we're talking
       the same stuff).  This only happened occasionally on hard driven
       rain and when snow or ice built up (I know its not suppose to, but
       occasionally we'd get ice,slush,sleet,yuk storms that would build
       up on the roof a couple of inches and water would migrate into the
       seam.  Possible if they sell a solid foam sealant/gasket to place
       between the sheets at the seam, but silicone or even most gasket
       material I've seen can't stand the heat or expansion rates well.
    
    After all that, I'd still use it and plan to on another small cabin in
    the planning stages.  It does slough off snow for the most part, and 
    the noise during a rain can be appealing at times.  
    

    
    
    ... was up in Home Depot (Nashua) yesterday and they had a few dozen 
    unusual roof rakes. They had a wide triangular metal blade and a poly
    coated extendable handle. Didn't check the price... but they certainly
    looked well made.
    
    								- Mac

>>                 <<< Note 50.399 by REFINE::MCDONALD "shh!" >>>
>>                             -< New rakes at HD. >-

They are $39.95.

Garry

I didn't like the look of those rakes - in particular, the sharp leading edge.
Also, they seemed limited in how high they could reach.  I noted a "limit 2"
sign at the store in Manchester.

				Steve

    
    
    Yeah, the reach looked like it was limited to about 16-18 feet. But 
    the sharp leading edge was a plus in my book. I've had vinyl rakes and
    I've had aluminum bladed rakes. My favorite is the aluminum bladded
    rake I bought at Hammar in Nashua. It's much easier and faster than the 
    more common vinyl type... and it hasn't been any rougher on the roof
    than the vinyl.
    
                                                                   - Mac

>     	Perhaps it's a seasonal thing, but I thought that the cost was closer
>     to $65/roll last I checked. Two courses on my roof would add $260 to
>     the materials (44' long house w/dormers). This is non-trivial.

	It's trivial compared to the cost of fixing water damaged ceilings,
	etc, and trivial do to it when re-roofing (assuming a tear-off,
	vs. a lay-over) than to retrofit later.

ps: me thinks you really meant to say "this is trivial"? :-)

	Also a warning to others.  Check your insurance *before* you
	get water damage to see if you are covered.  My parents, whom
	this year have significant water damage to some of their
	ceilings, found out they are *not* covered, and they can now
	*not* coverage until work has been done to correct the cause(s) of
	the problem.

	Also, when quoting roofing materials, if you are quoting prices
	for a linear foot of material, say so, as while it was obvious to
	me the previous several noters were quoting the $1/foot for a linear
	foot (which for the 3 foot widths is 3 sq feet or .33 sq yard),
	it can be confusing :-)

> Corrigate metal roofing.....
> Some downsides in working with this stuff.  

	If this is the stuff I think it is, another downside to it is
	that when snow/ice do slide off of the roof, it's like an
	avalanche, and can be quite dangerous.

	There is something that can be added to reduce this risk, something
	like some metal spikes or something near the bottom of the roof
	between each ridged seam, that will break up, slow down or
	something the snow when it comes down ....

    re:last
    
    	Based on the chunks of ice that broke off and came down from my
    conventional covered roof recently, it appears the danger exists either
    way. In my case, the main entrance to the house is on the side. This
    helps minimize the chance someone would get hit, but I understand what
    you are saying.
    
    	Based on what I know, and the input I've gotten, it still seems
    that the corregated metal roofing has more advantages than disadvantages. 
    If I go with it, I will leave the existing shingles so that even if I get 
    seam leaks, it might not equate into roof leaks. I also have a big dead
    air space (attic) between the roof and the living space. I suspect this
    will deaden any sounds substantially.
    
    	I still have a lot more research to do on this before I make a
    decision, such as cost, potential installation problems (i.e. sealing
    seams/ridge vent), longevity, etc., but I suppose I should move this
    discussion to a more appropriate topic ;-)
    
    	Ray

    
    re:last
       last-1
    
     The differences in "dangers" of snow/ice falling off of metal
    corrogated verses shingled roofs are actually quite dramatic. Shingled
    roofs tend to drop chunks randomly... whereas corrogated metal roofs
    tend to clear themselves in one or two massive avalanches. It's an
    amazing thing to hear from inside the house...
    
    The snow off the coorogated roof of my in-laws garage has actually 
    leapt a 10 foot gap to annihilate the roof of their sunroom. They now
    have the "curved spikes" at the eaves to attempt to slow or at least
    chop up the avalanche when it occurs.
    
                                                              
                                        			- Mac
                                         

    
    Corrugated metal roofing is not the same as "standing seam" metal
    roofing. One sees corrugated roofing on barns but the metal roofing on
    houses in the great white north is usually standing seam.
    
    JP

    re:407
    
    	I was made aware of that when I scanned roofing note 186, which is
    where I hoped to move the discussion to. The only reason it started
    here is to show it's impact on ice dams.
    
    	Ray

    
    What is the proper way to install the ice belt panels over existing
    shingles? I presume the top end slips under the shingles approximately
    30 - 36 inches from the edge, and the forward edge gets nailed down 
    with galvanized roofing nails. 
    Is roofing cement necessary or recommended (a) on the part which slips
    under the shingles, and (b) in the interlocking sides ? 
    
    Also, what is the best way to keep the nails from causing leaks in
    the panels?
    
    
    

    	I've never done it, but either HQ or Home Depot had an intructional
    display set-up. They should be able to walk you through it.
    
    	Ray

    Thanks, I'll go check them out. Now if only this @#$%^&*!!! sn*w 
    ever goes away...  :-(
    
    For now all the panels, roof goopie, etc are just resting quietly in 
    my garage.
    
    

    
    I recently got a copy of a 10 year UMinn study of "several thousand
    homes in 36 states".
    
    Basically it boils down to this:
    
      Ice dams on older un-insulated homes form at the eaves where 
      the water run-off meets the cold. Ice dams on homes that have 
      been insulated form *where the water comes out from under the 
      snow pack*. This means at the eaves if you leave things alone, 
      or up higher on the roof (where they're likely to cause more
      serious damage) if you rake/use heating wires/metal ice belt.
    
      They then go on to explain roof-over-roof construction that 
      apparently is popular in colder European climates, as well as
      "cold roof" designs involving very anal retentive insulation
      and ventilation.
    
    								- Mac 
    

.412>                                        Ice dams on homes that have 
.412>      been insulated form *where the water comes out from under the 
.412>      snow pack*. This means at the eaves if you leave things alone, 
.412>      or up higher on the roof (where they're likely to cause more
.412>      serious damage) if you rake/use heating wires/metal ice belt.
    
    My house was proof positive of this pehnomenon two years ago. After
    initial good results with a roof rake (.271), I later found serious
    ice dams just out of reach on my roof, where the snow ended after I
    raked. Result was inside damage to two rooms.
    
    Last year I installed a heat cable, and so far I've gotten through
    two seasons with no trouble (but some truly spectacular icicles
    where the cable comes down to the edge of the roof).
    

    
    
    There are two houses side by side where I drop my son of for daycare,
    one with ice melt cables and the other with sheet metal. During the
    worst of things this year the cabled house had sawtooth shaped ice dams 
    just above the cables and the other had typical dams, but above the 
    sheet metal (mean while my back roof had ice dams about 8 feet back
    where my roof rake didn't reach). 
    
    Both are a bandaid approach... but if I were to choose which bandaid
    I'd try in a pinch, I'd go with the cables. That way if things didn't 
    work out I could remove them a lot easier. Plus I just can't stand the 
    look of the sheetmetal on most houses (with the possible exception of 
    copper-eaved houses occasionally seen out west).
    
    								- Mac
     

What I have found is quite effective (on a shallow-pitched roof) is rolled 
roofing; think about a single 3-foot by 40-foot shingle that overlap and are 
tarred for half their depth (i.e. 18" overlap). Our house has a 3-foot 
overhang, so we have roll roofing going back 6 feet (so it extends at least 
three feet over the heated part of the house). 

In some ways this is very much like the metal ice shield, except that ice and 
snow don't tend to slide off (the surface is standard shingle style). So you 
get the humongous ice dams along the lip of the eave, but any standing water 
behind it would have to extend back six feet before it found any way inside, as 
long as the roll roofing is intact and installed correctly. We've had this on 
the house since about 1980 without any ice dam related leakage.

I've always wondered why you wouldn't get saw-tooth ice dams above heating 
wires; this is the first confirmation I've seen that they do happen.

Now, this year we did get some minor leaking through the roof at the place 
where the roll roofing ends and the normal shingles begin (in the kitchen, so 
it landed on linoleum floors; no damage except minor drips staining in the roof 
decking). Near as I can tell it's because the normal shingles are old enough 
that they're starting to cup and shrink; time for a new roof.

[Question for the roofing experts: any reason I shouldn't have bituthane (sp?) 
or equivalent installed over the entire roof, since it's shallow pitched? This 
is a Deck House, which means that the inside cathedral ceilings are the 3"x6" 
cedar roof decking, on top of which goes felt, 2" rigid urethane insulation, 
and shingles. Can I have them install a layer of bituthane between the 
insulation and the new shingles? I'll still wind up going with roll roofing 
along the eaves, since it's worked so well, but we've always had occasional 
random leaks through the roof in torrential downpours simply because the roof 
sheds water so slowly due to its pitch; the bituthane would be geared toward 
avoiding that.]

    Well, with Labor Day now past can the winter and those lovely ice dams
    in New england be far behind...
    
    I am looking for recommendations of someone in the Greater Maynard Area
    to install ice melting cables on my roof/gutters/downspouts.  Does
    anyone have someone to suggest?  Also, can someone give me some idea of
    what to expect this to cost (per job, per foot, ?)
    
    Thanks
    

    
    	I hope this is the right topic for this question.
    
    	Tuesday night I noticed a water stain on my son's 
    	bedroom ceiling.  I don't think it was there before	
    	Tuesday.  
    
    	We've got a two-year old hip-roof Colonial, and the
    	stain was about four feet from the side wall of his room.
    
    	That slope of the roof faces East.
    
    	We checked the attic and couldn't find any obvious sort
    	of water damage, though it appeared there might be a slight
    	water stain on the inside of the roof (hard to tell if it
    	was the wood grain or a water mark).
    
    	The attic is very well insulated, and has  ridge vent and
    	soffits.  
    
    	Any ideas as to what might have leaked and what kind of
    	action we'd need to take ?
    
    

    	Is the insulation in the attic exposed or is there a floor of some
    kind up there ? If exposed, measure from the nearest house end to where
    the stain is. It doesn't have to be exact, just close enough to get to
    the right set of rafters. Pull the insulation up where the stain is and 
    look to see if the water traveled to where the stain is. 
    
    	This may give you a clue as to where it's coming from. If the water 
    appears to be dripping onto that spot directly, try placing a large flat 
    pan (i.e. cookie sheet) there to verify. If so, it's likely you have a 
    plain old roof leak. We really haven't had the kind of weather yet to
    generate any significant ice dams.
    
    	Ray