I installed a new wood stove around the end of July and in the documentation for the stove it said that if I used the optional heat shields I would need 8.5" clearance between the rear corners and the walls. When we placed the stove we gave it 9" of clearance however we didn't yet have the heat shields and I didn't even consider that they would increase the width of the stove. Once I ordered the shields and put them on I realized that now I have around 7" of clearance instead of the 8.5". I talked to tech support at the stove company and the operator said that it did in fact have to be 8.5" clearance from the shields, even though the documentation doesn't mention anything about their size and how it affects the width fo the stove. However, he didn't feel we'd have an issue with 1.5" difference. I'm paranoid about not meeting the minimum clearance and possibly burning my house down so I want to do what I can to make this safe.
Since we installed the chimney based on the original location of the stove, if we move the stove to the correct clearance, we'd have to also move the chimney which is the last thing I want to do. I could also possibly put some UL wallboard against the walls but the pattern that matches the floor piece I have is around $450 each so that's just $900 to line the walls.
The other options I see having are...
1. Not worry about it and use a fan to circulate the air around the stove and hope it doesn't get the walls too hot.
2. Is it okay to cut out the drywall behind the stove and replace it with fire resistant drywall? If so, how far higher than the height of the stove would I need to remove the drywall?
3. ??? not sure what else I can do?
First I'd explore moving the stove. You don't say what kind of chimney you have but I'm going to assume somekind of metal chimney. It may be possible to move the bottom of the chimney a couple of inches without having to redo the roof. How hard it is to move the chimney will depend on how it's installed. If you have a single walled stove pipe that connects the bottom of the chimney to the top of the stove then it's really easy to move the stove. If the metal chimney comes all the way down to the stove then I'd explore if there is an adaptor piece made for that particular brand that is designed for a problem like this. You're not the first one with this kind of problem.
Yes you could replace your existing drywall with thick fire resistant drywall but the rating on something like that has to do how long it will keep a fire burning on one side of a wall on that side of the wall. I'm not sure how much protection it provides with a long term heat source.
I've also seen a double heat shield. This would do the trick I think. it makes like a baffle behind the stove. It lets are move behind both layers of steel. they stand off about an inch from each other.
I was able to move the stove and adjust the flue and ended up with about 10" clearance. Last night we fired it up for the first time and I was very nervous after a couple of hours. One wall wasn't even warm but the other wall was very hot.
My insurance agent gave me a booklet that said that a wall exposed to even 200 degrees for an extended period of time can catch fire through a process called pyrolysis. I don't know how hot 200 degrees feels so I don't know if my wall was that hot or not.
I've read that I could put some hearth boards behind the stove to protect the walls but that I need a 1" air gap between the board and the wall. I've never seen this where there's a gap like that. Is that normal? Or can you put something on the top and sides to make it look like it actually connects to the wall instead of just sitting off the wall an inch?
And, can anyone think of a reason why one wall wouldn't have even been warm while the other was so hot? Thanks!
Differences in some combination of where the hot spots are on the stove and how the air circulates near the wall to name two.
Closing the air gap top and bottom would largely defeat the purpose of having an air gap. Air rising in back of the shield cools the shield and the wall behind it. You could use some kind of grill work to make it look better.
You can't really tell by feeling because what we feel is how hot our hand in which depends more on how quick heat is transfered to your flesh. The temperature of the surface only partially influences this. For example we can reach into a 400 degree oven. The air doesn't bother us that much. Touching the cookie sheet will burn our fingers and reaching into a boiling pot of water, which is much cooler would result in a hospital stay and a long healing process.