Small round liner causes fireplace smoking. Spray foam in smoke chamber??!! By the way, do I need a stove pipe damper?

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Jan 10, 2022
Northeastern Vermont
Hello. After having done a ton of reading on this forum over the last long while, I am finally a member and this is my first post.

When I bought this house a while ago, the previous owner and her realtor had a brand new stainless steel liner and lock top damper put into the small fireplace so the house could be listed as having at least one (out of four) wood burning fireplaces that were functional.

The fireplace never functioned properly and would severely smoke up the house. Early on before I became educated, the certified chimney guy who did it wanted to blame atmospheric conditions, etc. Then he said "you can only make a small fire" among many other things (even though burning any amount of wood, however well seasoned, was a complete disaster any month of the year).

It appears that the liner is 8" round and it is very easy to calculate that it is nowhere near large enough to handle the size of the fireplace opening. The original rectangular masonry fireplace is several times larger in cross sectional area. It should have had a much larger rectangular steel liner, or something poured (although nobody wants to do difficult work to preserve the design and function of these amazing old fireplaces). Insulation was poured in around this severely undersized round liner, so it is pretty much ruined from the perspective of functioning as a fireplace. I started planning to install a wood stove.

The bricks of the hearth are not connected with mortar into a continuous surface, but rather just PLACED down with a bit of adhesive (caulk gun type) on the bottom of them. There is masonry all the way down to earth floor in the basement, so it is not so much an issue of fire or heat protection, but it was really pathetic having these loose bricks laying there as my hearth (not level either). I redid the hearth myself.

I had to re-position some bricks in the fireplace opening so that I could pass stove pipe through it. I could see the poured in insulation, and there were obvious large voids which upon investigation were found to be filled with SPRAY FOAM. This is right in the fireplace chamber.... one brick thickness away from the flames in my fireplace. Some of this spray foam was CHARRED and MELTED and STUCK to the BRICK! I will try to find the photos I took of it. Is this normal or accepted practice?

It takes 20 seconds to spray a couple cans of foam in there, and I can't tell you how many hours it took to locate it, remove it, and recement all those bricks back in place. This was done by a "certified" chimney guy that is still running around.

I was able to get a decent length of stove pipe in there and form a reasonable seal. It was quite difficult to find any kind of wood stove that could be accommodated by this small fireplace, but I finally got a used Jotul 3TDIC, so this is a bit of a happy ending. Despite the unpopularity of that model on these forums, it has been performing very well in the space with very clean burns, very little ash, and almost zero deposits in the chimney so far. The only issue is that burn times are pretty short. The stove never really deviates from ideal burn temperatures (300 to 500) no matter how much or how little air I give it, and whether catalyst in engaged or not.

I suppose I should not complain... but I almost feel like there is TOO much draft. Is this possible, and might it benefit from installation of a damper in the stove pipe?

Thanks for listening and for advice.
Here are some photos of the spray foam removal. Has anyone ever encountered a situation like this?
I thought this foam was combustible. They might as well have stuffed it with newspaper.

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I would be very troubled should I find that scenario in my home, wow. I could understand rockwool as it is not suppose to burn but would not be happy with fiberglass insulation either. If your stove and stove pipe temps are not running away from you and easily controllable with the stove air intake itself why bother with a damper, no need really.
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Yes, the ceramic type insulation would have been fine, but expensive.

There was some pink fiberglass too... and while I roll my eyes at it, I did not freak out about it. I mean, it seems to still be allowed by certain jurisdictions to close off a fireplace opening around the pipe from a wood stove with plain old fiberglass.

But the foam.... this stuff seems to really burn well and hot (in addition to giving off chemicals at the start).

Thanks for advice on damper. Yeah, the little old Jotul in the current chimney has the most usable range of air control I have ever operated on a wood stove. Open is hot but not too hot. Closed is cold but not too cold.

I suppose I'm just wondering about the short burn times and if that could be a result of TOO much draft (sucking a lot of heat out the chimney). Though maybe this is all I can expect from such a tiny stove? As I said, I am sure i will appreciate the very good draft and relatively low heat output in the spring and fall seasons here.

I'm sure there is a bunch of leakage going on, preventing it from running in full catalytic mode... due to warped back and top baffles. The air can escape through the regular route. I have the new baffles, but seems I now need to replace one more part (back grate?) that is warped... in order to get it fitting properly.

But even without catalyst at all, I would have expected longer burn times. It is not much better than my antique little 'morning stove' that is in the kitchen. That thing is completely unsealed.
I suppose I should not complain... but I almost feel like there is TOO much draft. Is this possible, and might it benefit from installation of a damper in the stove pipe?

I had too much draft and short burn times. Installed a flue damper and got slower burns and more usable heat. Took some trial and error to find the balance between the intake damper setting and the flue damper.
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