Conference 7.286::home_work

    	I don't know alot of detail, but i was told of a tip...
    
    	When you are laying your blocks, get a bag of marbles and put
    	one in each corner as you lay each block, tap the block down
    	until it rests on the marble. As long as your 1 block is square
    	the rest will be too.. Also it will ensure uniform distance
    	between blocks...
    
    			Steve
    

	Did you look in the "do it yourself" section of your local 
	bookstore?  There must be many books with detailed instructions
	on chimney building.  One that I can think of off the top of
	my head is the U.S. Navy Bureau of Personel's "Building small
	Buildings and Houses" or something like that. 

	Also if you have access to the Mother Earth Bookshelf catalogue
	there should be something in there.  

	If you still need names, let me know.  I will be on vacation next
	week, but back the week after.

	-gary

    I have a copy of "Wood Heat Safety" by Jay Shelton.  It is
    a very good book for installing a wood stove.  It discusses
    several different types of stoves and chimneys.  I used
    this book when planning my chimney.
    
    I built a 26' chimney for a woodstove that is on a hearth in
    our living room (built the hearth too).  I had to get two
    permits - one for the stove and one for the chimney.  I'll
    put the details of the chimney in the next reply.
    
    
    Mark
    

Although your chimney will be somewhat different since your stove will
be in the basement, I think some of the details of my chimney will apply.
    
The chimney is 26' feet high - it only needed to be 25', but for reasons
below it was easier to make it 26'.  The 25' comes from 21' to the edge of
the roof plus 4 more feet to get the top of the chimney 2' above any roof
within 10' (all this is in the Wood Heat Safety book).  

I calculated that an 8"x8" liner was the proper size, so I bought 16"x16"
one piece chimney blocks.  The liner is actually 7 1/4" square and the
hole in the 16" square block is a full 8", so there is a little air space.
After pouring a "pyramid-like" base (40" down to get below the frost line),
I started laying the blocks and liners.  Each block is 8" high and each
liner is 24".  I would lay 3 blocks, then slide one liner inside.  To give
the mortar a change to set, I would only build 4' a day.  This also gave
me a rest because after I was 20' up in the air standing on a 2x10, it 
was time to get back on solid ground !

I started the first liner on a 4" bed of mortar to offset the liner joints
from the block joints.  In each joint (between blocks) I used 5 brick ties
(1" x 6" galvanized metal strips).  I put 2 on the side next to the house,
bend them into "L" shape and nail one side into the house and put the other
side into the mortar.  Then put one brick tie on each of the other 3 sides.
These are used if you want to face the blocks with nice looking bricks.

The reason for going 26' was to eliminate cutting another liner - used 13
liners and 39 chimney blocks.  For the cleanout, you need to cut the one
liner one and one block - I used an abrasive cutoff wheel on my circular saw.
I think this was a mistake because the fine dust got into the saw and
ruined the commutator.  I have since learned that they make special saws
for this (with filters).  You can rent them or have the blocks professionally
cut - Charles Precourt in Sudbury does this.

I built this chimney two years ago.  I read a few books and drew some plans
which the building inspector approved with one suggestion (the one about
offsetting the liner and block joints).  I have not finished laying the
red bricks though - it will take 900 bricks and I have 100 in place.

One more thing, the chimney blocks weigh 90 pounds.  Once I was higher than
I could reach, I tried to pull one up on a rope - not a good idea.  However,
since the block has a hole in it, you can easily put your arm through and
rest in on your shoulder and walk up a ladder AND still be able to hold on
with two hands.

The chimney also has a metal cap - a requirement for chimneys for woodstoves.
Another suggestion I got from someone else (who got it from his building
inspector) was to put Perlite in the space between the block and liner.  This
filled the air space, the theory being that the liner would stay warmer thus
reducing the possibility of creosote buildup.


Hope this helps,
Mark


One other book is "Masonry and Concrete Work" by Max Alth.  There is one
chapter on building chimneys and fireplaces.

    

    re: .4
    
    Thanks for the info.
    
    How did you interface the chimney and the house?  Did you remove
    the siding or just build next to it?  Did you seal the gap in any
    way?
    
    -joet

    I think you mean Vermiculite, not Perlite, for between the liner
    and the blocks?
    
    Don't cement the liner to the block - if you do the liner will crack
    when it expands from the heat.
    
    I think you need 2" between the masonary and any combustible surface,
    in theory.  Building inspector might have an opinion on that one.
    
    You can cut cement block (and tile liner) by drilling a series of
    holes with a carbide masonary bit and then going at it with a cold
    chisel and hammer.  The concrete isn't too bad to drill, but the
    tile liner takes FOREVER to drill.  It is possible though.
    
    

    When I had a chimney built in Townsend, the building inspector
    wanted 2 inches between the brick and the wood around it.  
    Then, the 2 inches had to be filled with cement as a firestop
    (so if there's a fire on one floor it can't spread to the
    other floor as easily).  So what you have is brick two inches
    away from the wood, and cement filling the gap.  It didn't make
    any sense to me, and still doesn't, but that's the way he wanted
    it, and that's how mine is.
    

    re: .5
    
    Yes, I removed the siding so that the chimney blocks were next to
    the sheating.  Since I planned to install siding (with styrofoam
    insulation underneath) the following year, I just made sure the
    insulation fit snug with the chimney blocks.


    re: .6

    Nope, I mean Perlite !
    

    The only requirement for a 2" clearance was from the outside edge
    of the metalbestos thimble to any combustible material.  If you
    use the one-piece chimney blocks, you have very close to 4" of
    concrete between the house and the liner.

    
    Mark    

    

    Isn't Perlite some sort of foam plastic beads?  I may have an erroneous
    idea of what Perlite is.  
    Anyway, Vermiculite is puffed-up bits of mica, and absolutely 100%
    non-combustible as well as an insulator.  
    
    Steve

    Steve,
    
    Perlite is processed volcanic ash.  I am sure it is non-combustible,
    but it sounds like vermiculite may be a better insulator.
    
    
    Mark
    

.10 reminded me of a "juvenile" mystery novel I found at a flea market
and read to my daughter last year. Salting a perlite mine was part of
an elaborate plot to get clear-cut logging rights in national parkland
in Colorado. 

Perlite is, as .10 introduces, formerly liquid volcanic rock that
solidified while still under pressure in the presence of gas. This
means that there is gas inside the rock when it is mined. Heating the
rock to its melting point allows the gas to expand, foaming the rock
into a light-weight fire-proof insulator.

Glenn

    Sounds like either one of 'em would work....
    

    The bottom line is to use what the building inspector 
    says to use......
    

    re: .4
    
    You said the chimney had to have a metal cap.  Is this in
    Massachusetts?  I'm buying a home in Gardner with a woodstove. 
    It's on a chimney much like the one you described.  But I don't
    recall a cap on the chimney.  
    
    I wonder if the fire inspector will notice when he does the smoke
    alarms...
    
    Elaine
    

    I have a floor to ceiling (24') chimney in brick that I am
    thinking about refacing with stone.  The whole deal sits on a
    slab so no problem with weight.  How should I go about this?
    Wall ties?
    Some kind of mesh?
    
    The stones would be fieldstones.
    Tom
    

    You may have a problem here.
    
    Most of the time, a fireplace on a slab has structural concrete
    beneath the slab to support the extra weight. Especially if the
    fireplace is 24 ft tall. If there is an extra concrete pier beneath
    the fireplace portion of the slab, it's probably shaped just like
    the fireplace. Build a fieldstone face around the fireplace and
    you may find that the extra pouring under the fireplace doesn't
    extend the the area where you're erecting the fieldstone. If that
    happens, you'll find the shear forces on the concrete slab will
    rupture it ... concrete doesn't do well in tension, only compression.
    
    Good luck!

Blue-skying for a bit...

My wife and I are designing a log house and we are wondering about maximum
chimney heights.  The central part of our house will be a great room with a
cathedral ceiling and a four-sided stone fireplace in the very center with
a chimney extending to the top of the cathedral ceiling.

Ignoring the problem of extending the chimney through the king rafter of a 
cathedral ceiling, is the height alone going to be a problem?

Consider, the great room is 30' x 35' with the cathedral ceiling running the
35' length.  A full basement (10') + first floor (10') + second floor (10')
+ cathedral ceiling (15' - assuming 45 degree pitch) + extension through roof
(5') = 50'.  Feasible?  Impossible?  

Should such a fireplace be constructed BEFORE the house is built?

Would a 5' square hearth tapering to a 4' square chimney cut it?

How about a block core covered with stone vs. solid stone?

Paul (lusting for the thermal mass of such a fireplace in a passive solar house)

Should be no problem, as far as I know.  The Old Faithful Inn in Yellowstone 
(the largest log structure in the world) has a free-standing fireplace up the 
center that must be 200 feet tall - and about 20' across at the base.  (how's 
that for thermal mass?).

I'd go with stone-faced block.  And I'd build it after the house was up.  I'd 
hate to see the crane smack the chimney with a bent - TIMBERRRRR!!!

Paul

    
      Altough many years ago it was normal to use the (LARGE) chimney
    to help support the house, this is not done anymore. Most building
    codes require that the framing of the house be ~2" away from the
    chimney to prevent the wood from catching fire. This means that
    every house you see has what amounts to a Free-standing fireplace
    from top to bottom. (I KNOW the one in my log cabin doesn't touch
    the framing and it's at LEAST 35' from top to bottom!)
    
    					Kenny

    Jim Rizzitano
    Summet::Rizzitano
    DTN: 227-3691
    
    In the near future I will be building a double flu 8X12 chimney from my
    basement, through a closet on the first floor and through a closet on
    the second floor and up through the roof. My plans are as follows and
    would like some sanity checks.
    
     * Pour a 12" slab in the basement to carry the weight of the chimney.
    
     * Begin by placing and leveling and plumbing two flus and encasing
       them with chimney block. (should I fill between the flu and chimney
       block with mortar ?)
    
     * cut through the roof when I get there and begin courses of used
       brick which look alot better. (roofers will take care of flashing)
    
    

    >   them with chimney block. (should I fill between the flu and chimney
    >   block with mortar ?)
    
    No, the flue tiles want to more or less float inside the block.
    If you mortar them in solidly, they'll crack when they heat up and
    expand.  You can fill the space with vermiculite, if you want.
    
    The joints between flue tiles should be cemented with fire clay,
    I believe.

    re: .1
    
    Please do not recommend the use of vermiculite, as it is banned in many
    states.  There is a product on the market which is a combination of
    vermiculite and portland cement which can be used.  Check with a local
    mason or chimneysweep.  The rationale is that if there is a break in
    any of the tiles, the vermiculite will fall into the chimney further
    blocking it.  The portland cement in the mixture above will prevent
    this.
    
    Dan

	The footing should extent 12" from the chimney base on all four sides.
12" thick may be alittle over kill. It's my understanding that the footing must
rest on undisturbed base not on top of an existing floor. A chimney this tall
should have reinforcing rod (rebar) 6" on center, 1/3 to 1/2 way up from the
bottom. If it's going next to and existing footing, I'd pin it to that as
well by drilling holes and extending the rebar grid into them.
	First frame the rough openings needed above leave 2" clearance on all
sides. Drop two diagonal plumb bobs from the attic and work your way down to
the footing in the basement. Outline the chimney on the footing and your ready
for the first course.
	The first course needs to be fitted for the cleanout doors. This is done
with half blocks (wrong name? 4x8x16) gray (cinder) bricks or you may be able
to buy prefab chimney blocks? Flue tile is cut with a masonry blade in a
circular saw. It dangerous and dirty, do it out side.
	As to filling between the flue tile and block "DON'T". But leave any
squeeze out between the block and the tile stay. If you need alittle more add
it on the next course. Each flue tile should be pinned randomly 3 or 4 times.
This is  enough to hold things in place, while at the same time providing a
thermal break. Without it something will fail prematurely. Use refactory sp?
cement for the flue tile joints. It's not necessary for the all the tiles but
good practice at least a few tiles above and below where the flue pipe enters. This
is the same stuff that should be used in the fire box of a fireplace. It has a
high clay content and can take the extreme thermal cycling. It can be bought
in a caulking tube or five gal. buckets. I've bought it at Spag's, but any
good size hardware store should stock it. I take a tube up on the roof
when I clean the chimney to use it to do minor crack repairs to the Chimney
cap.
	You should lay some sort of metal strapping tying the side by side
chimney block together maybe every over coarse. Here's a trick I've hear of
but never actually tried. Place standard size marbles in mortal at each corner
of the chimney blocks. This will hold the joint to the desired thickness 3/8"-
1/2" while the mortar sets up. This would be a big help to the beginner mason,
because if the mortar is just a little to soupy these blocks are heavy and
will cause headaches.
	Now about the bricks and flashing. I'd use the best new bricks you can
find for the exterior work. They sell some designed to look like used but are
much  more durable than some used bricks. If you know you have a good used
brick go for it. Here a porous brick is bad, they suck up rain water freeze
and deteriorate quickly. You can get a relative feel for there quality by
placing in a bucket of water and watching the bubbles or maybe weight them
before and after the bubbles stop. You can quickly develop a feel for a bricks
quality, color will also come into play for the used bricks.
	The best time to apply the flashing is while your laying the brick. I
know because we ran out of lead and just left space on the outside edge for the
lead and mortar to be applied later. These few joints have needed repair since.
Flashing is not that hard to do, just keep reminding your water flows down
hill. It is hard to describe without pictures but I'll have try at a later date.
	This job is too tough for the average do it your selfer. The skills
required aren't hard to come by but are tough to learn as you go because the
lower first laid courses got to carry all the weight. Go slow maybe 4 feet each
day, give things a chance to setup.
You could come out OK. I took a Night Life course to get my confidence level
high enough. Bare minimum do your homework and spend a few nights at the
library. Or maybe donate a Saturday to helping a mason, mixing mortar and
watching his every motion.

Good luck,

/Jim



Start low and overlap seams at least 4". First cut to length be sure to
leave an extra 12" on the first piece. This piece needs to wrap around both
sides where the step flashing goes. Start by bending an 1 1/2" 90 deg. bend
which will rest on top of the last coarse of brick laid. This should be about
2 courses about the lowest point on the roof line. Now cut a 1/2" slit every
2" on the 1 1/2" edge. Bend this cuts up at a 45 deg angle this will provide
tabs which will hold the lead in place when mortar is setup.

    RE: .3
    
    Where did you take the course? How much was it?
    
    Marc H.

    reply to .4 

    	I took it at Assabet Valley Vocation High School Located in Hudson. It
    was about 5 years ago but it cost ~$100 +- $20 and you need to pick up 
    about $25 worth of masonry tools assuming you already own a level.
    	We met once a week for ten weeks for ~ 2 1/2 hours. The first 2 classes
    were classroom lecture, question, answer type deal. Then is was all
    hands on, we built things like stairs, walls, and a fireplace. The
    instructor left it up to the class as to the types of projects covered.
    We used a sand and lime mixd for the mortar. Which worked like the real
    stuff but disassembled real easy before the next project got started.
    	Back when I took the class it was offered twice a year, in the fall and
    spring. The sign-up for the Spring session should be coming up soon,
    if it's still offered. You want to talk with the Adult Education Office
    located at the high school.

    /Jim    

    Thanks....
    
    Marc H.

    
  I'm hoping this is an ok note for this question (cross posted in STOVES)
    I'd like to find out what people do about chimneys warming up an
    attic space. We have a very efficent woodstove and over the past
    month it has been cranking out the heat. This is the first winter
    for us in this house.  It has a gambrel roof and a center chimney 
    which probably has lots of exposure in the attic area.  The attic 
    (which will be investigated this weekend to be sure!) is about 4-5' 
    high and about 22' long (one room has a cathedral ceiling).  We are
    experiencing ice dams which are forcing moisture/leaks onto 
    ceiling areas which border the dormers.  We suspect that a very heated
    up attic exacerbates the problem.  I'm hoping that someone in this
    file has seen such a situation and can offer some advice.
    
    thanks
    carol

                                                                          

    Carol - it *may* be possible for you to build a frame around the
    outside of the chimney within the attic space and insulate it like you
    would a wall. If you do that, you need to keep the wood of the frame at
    least 2" away from the chimney and you would have to use unfaced
    fiberglass insulation. The idea being that combustable materials must
    be kept away from the side of the chimney. 
    
      That said - the chimney is likely a very small part of your problem.
    You likely have insufficient insulation and/or insufficient attic
    ventilation. You need also check for air *leakage* paths into the attic
    from the house. Around the chimney and around pipes are the most common
    paths. It is extremely common that houses do not have enough
    ventilation of the attic space.
    
    			Hope this helps a little,
    				Kenny

    RE: .15
    
    I would be very surprised if the chimney was causing a huge amount of
    warm air in the attic. The pipe should be insulated...........
    
    Marc H.

    >Carol - it *may* be possible for you to build a frame around the
    >outside of the chimney within the attic space and insulate it like you
    >would a wall......
    
    IMHO this would NOT be a smart thing to do! Insulation a considered a
    combustible material and is not advised to leave exposed (except in an
    attice type situation between the ceiling joists).
    
    When I was finishing off my attached familyroom, I asked the building
    inspector if I could just insulate or did it need to be sheetrocked
    (this was to obtain a CO). He absolutely said it had to be sheetrocked
    because of the reason above and it was code. I never really thought
    about it before. Then I read the warning label on the bag & on the
    paper backing & even Owens Corning says the same thing.
    
re -1    I would seriously reconsider using insulation around a chimney. Like
    others have mention, check your ventilation. If you have soffit vents
    make sure they're not blocked. As far as the chimney being too warm,
    I'd talk with a mason or someone who specializes in fireplaces & see
    what they would suggest (call a few people)>
    
    Alan
    

    Re .18:
    
    The PAPER FACING on (faced) fiberglass insulation is combustible,
    and a warning to that effect is printed directly on the paper.  If
    you read further, that same warning message also states that
    the FIBERGLASS INSULATION itself is non-combustible (after all,
    it IS glass).
    
    Using unfaced insulation around a chimney would be safe.

    re .19
    	I thought about it after I entered the note, so I checked when I
    got home. The warning label states to read the warning label on the
    outside packaging but did continue to say that the paper facing on the
    insulation was flammable.
    	Unfaced insulation could be used. Personally I'd feel better
    talking to a pro first. Bottom line is that there's possibly something
    else causing the problem, as been previously mentioned.
    
    Carol - have you had a chase to inspect your attic? Let us know your
    	    findings.
     
    Alan
    	

	    An easy way to determine if yours is a ventilation problem is
	to check the attic for frost.  If you have adequate ventilation, 
	you shouldn't be able to find any.  If all the rafters are frosted,
	the lumber was too moist to begin with.

					Tim

    The attic inspection shows an uninsulated spot over an old bathroon fan
    which is probably not helping matters.  and it looks like there could
    be a few more bats of insulation placed on one end of the center
    section but otherwise - no real horrid spots.  One thing we did notice
    about the design of the roof .. tell me what you all think :  remember
    it's a gambrel and the part where the top 'cap' slants down to meet
    the other part of the roof which is sorta at an angle has a trim piece
    on it.  Not just shingles but an actual separation with the trim on it.
    hoping i'm making myself clear.  it's quite common for gambrels (as we
    look around the area i've seen all but 3 have that feature) it seems
    but I wonder if that is not helping matters.  it looks like this :
                   /||||||||||||\
    	          //            \\
                 //              \\
    	        // |            | \\
                   |            |
     dormer \      |            |   <full dormer
     window /      |            |   <across back
    
                  |

    I'm about to call in the BI to check things out as we install our new
    woodstove.  The basics are these:
    
    New chimney was built using chimney block and 24" flue liner sewctions
    as in the base note.  This chimney extends from the basement floor
    through the first floor, through the second floor, through the second
    floor ceiling through the roof and 3' above the roof.  This is a cape -
    this new chimney is about 11" away from the old chimney.  The framing
    and floors were cut to allow about 2" (actually, 1" to 4") space
    between the chimney block and the framing/floors.  This means I can see
    from the second floor ceiling all the way down into the  basement
    around the chimney.  
    
    There seem to be no visible attachments between the chimney block and
    any framing.  One section of the application for the permit states "all
    chimneys shall be secured at each floor level or at least every 10' and
    adequately supported."  What exactly would qualify as securing the
    chimney?  Does an interior chimney block chimney need securing?
    
    The app goes on to say "All spaces between chimneys, floors, and
    ceilings shall be firestopped to a depth of 2 inches".  What would
    qualify as firestopping if I can't use wood?  Or, as 311.7 says, does
    the chimney block itself qualify as non-combustible material and I can
    safely fill those spaces with wood?
    
    Thanks,
    Dana

    To answer my own question:
    
    Interior masonry chimneys need no support/securing to interior framing. 
    (Thank God for that - we've got enough things to do)
    
    There can be no combustible products within 2 inches of the exterior of
    the chimney, even though its a chimney block chimney.  Aluminum
    flashing, durock, and other non-combustible stuff can be used to fill
    the spaces.  
    
    Dana

   
 Hi, I just had a chimney built (in central Mass) and it is finally complete
     on the exterier of the house.  Most of the work was done during the 
     recent indian summer but the last 3-4 feet were finished yesterday
     (very cold outside).  The mason use an antifreeze in the mortar and
     tented the chimney using a quartz heater pointed at the chimney.  I 
     am still a little concerned.  There are 4 side to the chimney, are the 3
     not facing the heater going to possibly freeze?  I live on top of a hill
     and it get quite windy so the heat does not stay very well in the test.
     The mason nailed some small boards into the roof to hold down the tarps,
     will the holes left in the roof be a problem?  Are there any questions I 
     should ask him or work I make sure that gets done before I pay him?  
     What is the standard guaranty on this kind of work (if any)?
 

                               Thanks for any and all info


                                         Tom

    I have center brick chimney.
    
    I noticed that there is a good 8 inches of air space
    between the back of the fire place and the sheet rock wall
    in the kitchen. I'm interested in claiming some of this air
    space with built in cabinets. The desired locations of these
    new cabinets would be directly above and behind the fireplace 
    opening:
    
                          || ||
               desired  { || ||
     kitchen   location { || ||           living room
    			  |/ \|
    			  || fireplace
                        |?||__
    
    Whats the typical minimun distance |?| required bt the
    back of the cabinets (assume combustable) and the
    brick chimney? 2 inches?
    
    Suppose I put aluminum flashing on the back to the cabinets? 0"?     

    The Brookline, NH, building inspector and fire marshall require
    a minimum 2" clearance between the chimney and nearby things.
    One is allowed to have some trim covering the gap but in case of
    fire they want to be able to tear it away and look into the 2"
    space.
    
    Towns may vary, check with your own fire marshal and/or
    building inspector.
    
    ed

    We had a similar experience in Mass.  Our building inspector required a
    2" gap between the fireplace/chimney and any combustible materials. 
    Steel studs were acceptable, however.
    
    Elaine

When I built my brick chimney in Mont Vernon, the only requirement was
a two inch clearance from FRAMING. Roofing and flooring are allowed to
abut. I thought it an odd restriction to I asked the building inspector
very specifically about it just to ensure that I hadn't misunderstood.

Here's a drawing I swiped from another note:

    				_______
    				|     |
    	------------------------|     |--------------------------
    	|			|     |                         |
    	|			|     |		Roof		|
    	|			|     |				|
    	|_______________________|     |_________________________|
    	 |		________|     |________			|
    	 |		|	|     |       |	  <slanted	|
    	 |		|	|     |       |   bluestone	|
    	 |		|_______|     |_______|			|
    	 |		|		      |			|
    	 |		|		      |			|
    	 |		|		      |			|
    	 |______________|_____________________|_________________|
    

My question concerns the "slanted bluestone" pieces on the shoulder of
the chimney.  How should these things be fastened?  Ours is sliding
off slowly but surely.  

Should the mortar bed on which the bluestone has been set be
sufficient to hold the bluestone in place?  

One person said that the pieces should be "pinned" somehow, like with
rebar pins, to positively prevent them from slipping.  Anyone know
about this?  What sort of drill bit would I need to drill holes in
this rock?

Thanks for any help,

-Chris