Wall Thimble Install

Great idea on the firestop!

 

The install is under way. Almost done actually. Question, do you also silicone around the vent pipe as it goes through the thimble on the inside? The manual only speaks to doing it in the outside. My other stove, installed professionally, has the silicone. Is there any advantage, disadvantage to doing so?

 

I didn't on my install but yesterday when I cleaned the furnace, I remove my exhaust tip on my vent to do the brush once over. When I went to compressed fit it back together, the whole assembly slid some in the thimble, Mind you I do not have a wall brace inside If I had put silicone it would probably not move. It's more for air penetration stoppage. I have heat resistant insulation inside the thimble so I didn't bother. Now I need to get a wall brace and get at silicone the thimble Silicone on the inside would prevent any air leakage coming out of the wall if any.....plus double the vent tightness in the thimble.

 

I didn't on mine only because I don't want to have to fuss with cutting the silicone off when I pull the vent at the end of the season to thoroughly clean. There is a slight air leak though if you don't put anything around it. I with they make some type of 3" silicone "ring" that would go around the vent just to seal it up a bit but I've never seen anything like that.

 

I'm pretty sure I've read that you're not supposed to put silicone on the inside thimble "in case there is smoke inside the wall". Now...you're not supposed to have a pipe joint inside the wall anyway, so I'm not sure how there would be smoke inside the wall unless the pipe breaks down, in which case you've got bigger problems anyway.

I siliconed mine because the exterior walls of my house are poorly air sealed and I had a pretty decent draft coming through.

 

Yeah, having a joint in the thimble does not sound like a wise thing to have. I agree with yourself and others that it would be good to prevent any draft.

 

Same thing happen to me because I didn't have my brace fixed to the wall yet. I did have high temp caulk inside around the vent but it was wet still. The vent slid in and ruined the nice bead of silicone I just had done. Had to redo it lol