Evap: How close to wood walls can I get?

[MapleME]

Well, before i call the town and find out what "code" is for wood stoves etc, i thought I would find out what I need to do to get the evap as close to the walls of my shack as I can (mainly because I have absolutely no extra room). My stack goes straight out the back of the evap, through the wall of the shack and then makes a 90 degree turn north...i.e. I can get pretty close to the outside wall. Right now, the shack is t-111 sides with studs on in the inside and a wood floor. i wonder if I put some sheet metal up on the 2 walls and floor can I get closer?

Much thanks
MapleME

[Haynes Forest Products]

I would insulate the wall with fiberglass without paper on it and then drywall with 5/8s and then put 1/4 tile backer and call it good. I dare someone to cause a fire in that wall with direct flame to the cement board. If that does not make you happy then go to home depot and get hat channel in the drywall section and use it to shim out a piece of sheet metal and your all set zero clearance.

[peacemaker]

rock then a air space then your cement board or tin

[hard maple]

why would you call the town???
Is your sugarhouse insured???
If your headed in that direction ...good luck

[Amber Gold]

I think fire code is 2X the pipe diameter to a combustiable surface. If you have a non-combustible surface with a 1" air gap to the combustible surface you can cut the distance in half. The non-combustible surface also needs a 1" gap top and bottom to allow air to circulate through and the spacers you use to create the 1" gap need to be non-combustible as well. I'd use 1/2" cement backer board (Durarock or equivalent) and cut up 2"x2" pieces of Durarock and stack them 2 thick to create the 1" gap. When you screw the durarock to the wall screw through the stacked pieces. This is what I did for my woodstove and it worked great.

The problem isn't only flames coming in contact with the wall. The other issue is the combustible matieral exposed to high temperatures, which over time lowers the ignition point of the material. This is the reason for the air gap, it keeps the temperatures down. Also I wouldn't put the insulation in. Personally I'd want to maximize the transfer of heat away from the walls and I think the insulation would reduce this and help to retain the heat.

My opinion.

[peacemaker]

i agree with u amber gold i wouldnt insulate and i use copper pipe cut to 2 " then screw thru them

[3% Solution]

MapleMe,
May I add my two cents worth of being a retired firefighter.
First off you need to be 36" from any combustable material.
Hang a piece sheet metal between the arch and the wall and you can cut that down to 18".
I would make some type of stand to hook the metal to, then it isn't in contact with the wall.
Keep in mind that 5/8" sheetrock is also called firecode sheetrock, that means that it will take direct flame contact for 1 hour (per single board layer) before comprimising the board.
Heat will still radiant through the board and may ignite the paper covering on the face.
I would strongly suggest the stand and metal option.
Again, just my two pennies!

Dave

[hard maple]

3% just curiuos
what percent of sugarhouses have you been in that have 36" of clearence
my guess would be around 3%
unless your title is the county building inspector

[MapleME]

hard, do you really think I would tell the town??????? geezum! (hence my post here!)

Of course, calling them to find out what wood stove fire code is would be giving up any secrets would it???or does that make you uncomfortable too?

[3% Solution]

HardMaple,
Ouch that hurt!!!
MapleMe asked about the code and I gave him some info and to my knowledge it is factual info!!
If you read along to the third sentence you will see that you can be as little as 18" away from a combustable surface.
We don't have a county building inspector here, it's a town building inspector, and that I am not.

Dave

[Bucket Head]

I'm not trying to hijack this post, but everyrone should think about how close their stack is to their rafters also.

I have seen some very scary looking walls, rafters, and roof jacks. All of them were black and/or charred. One sugarmaker even told me he caught his rafters on fire one night! He had to call the Fire Dept. He was very lucky to say the least.

This leads me to the 90degree elbow through the wall and up the outside of the sugarhouse question. If you have enough room, it would be safer to do it this way I would think. I don't know how much it would alter the draft, maybe it would have no effect.

Any thoughts on this?

Steve

[Amber Gold]

Steve,

I thought of this and my roof jack will be the sleeve style which extends down into the sugar house protecting the rafters. I think Lapierre makes the one I'm getting.

[MapleME]

Bucket, depending on the evap model you have will greatly help/or inhibit your idea- mainly because you dont want any turns in your evap stack if you can avoid it. Many of the evaps have the large, wide opening stack on the top of the evap so going straight up in the best thing. My model has the stack nipple on the back, so shooting out with a 12" metalbestos piece through the side wall of the shack and then going up will be ok. much discussion has happened on bends in stacks etc.
MapleME

[Pete S]

The information given about the 36" then reduced to 18" with the "shield" and air space would hold true here in WI, regarding the building code.

The noncombutible AIR SPACE is what is key here. Building up a "non-combusitble" surface will still allow the transfer or conduction of heat.

I'm thinkin' that an even greater concern is the single wall pipe penetrating the wood wall.

Check out "thimbles" on a search engine for some homespun builds,...........or spend the money and buy an assembly.

You may as well want to consider your clearance on the outside of your building as it's being subjected to excessive heat with the single wall pipe.

Is there anyway to penetrate your roof and keep the pipe inside? Horizontal spacings (roof penetrations) can be a bit easier to achieve, as opposed to verticals, as in wall penetrations.

Just my $.02

Pete

[SBClorite]

Be sure all of your pipe is well secured too.
We had stack pipe through the roof with a roof boot. The last section of pipe, before the boot, settled slightly (screws pulled) and the whole stack shifted about 2" to one side.
There was so much steam that we didn't notice until the solder from the roof boot was dripping down on the stack base and into a pail of water. One bit landed on my arm after splattering off the base... that got my attention.
Lucky that we had plenty of clearance to the rafters and that the other sections of pipe were well supported to the loft bridge, so the whole thing didn't move a lot more.
You may not have seen too many sugar houses with arches 36" from the wall (or even 18"), but you hear of plenty that burn down. A little fire retardant and some common sense are cheap insurance. You usually don't have a problem until it is too late!
3% is giving good advice to stay out of trouble. You may be able to go closer to the wall, but is a few inches worth rebuilding a few years later after the one time that things got hotter than the rest?

[3% Solution]

Thanks Pete and SB,
That's all I'm trying to do here.
Just looking at 22 years as a firefighter and "Improper woodstove (cause that's what we've got here is a big wood stove) installations."

[peacemaker]

if u do as was mentioned way back with the space and a piece of cement board and if the wall behind the arch is ext... why couldnt you go low to the ground on the outside and drill in some of those 3 in soffet vents this would draw in cold air ....no ?my problem is my finishing room is behind there now so i thought why not take down the osb wall in between and the one stud frame a header and the suspend a cement board that would ad heat to the finishing room

[3% Solution]

Hey Peace,
It's the radiant heat that's the problem, it has to be cut off before the combustable.

Dave

[peacemaker]

thats what i mean do as we said with the double wall space but intruduce some cold air into the middle

[3% Solution]

Piece,
Check your PM!!!

[CityMaple]

Here is my contribution, that is if you have a concrete floor to work off of. Lay up 4" concrete block now you do not have to worry about it because you have a non combustable wall. I belive that you could dry stack them and get a product called quick wall, you plaster it on the block and holds them together with out the mortar. That in effect would be the same as a block chimney and that has a zero clearance to wood in the construction of a house. You code guys please let me know if i way off.

Joe

[peacemaker]

thats not a bad idea u could lay them all the way up to the roof

[Haynes Forest Products]

I have 24 guage sheet metal that is mounted 1 1/2" of the OSB that is painted white. My 2x6 wood fired and the oil fired and now my 3x10 oil fired have all been within 10" of the wall and it hasnt even scorched the paint beneath the tin. As soon as the heat starts to radiate to the sheet metal it starts convection air movement and keeps the wall warm but not burning hot. I think its better to be safe than sorry but I think over kill to have 24" of space with fire retardant wall.

[WESTVIRGINIAMAPLER]

I have 10" stainless stack thru rafters on 24" centers and I have all the exposed rafters on both sides of the stack insulated with ceramic blanket. To me this is a good, safe, and cheap insurance policy on the building. Remeber, better safe than sorry and you have put a lot of time of money into your sugarhouse to see it go up in flames.

I have my building insured for a lot more than it cost me, but I still want to take every precaution I can.