I have a woodstove on the 2nd floor of my house. The stovepipe goes straight up through the ceiling into the attic, and then through the roof. There is a small gap between the stovepipe and the firestop radiation shield (see photo). This gaps allows inside air to vent directly into the attic. Is this normal? What is the best way to fill this gap, if any? Thanks.
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Replies
Is this normal?
Well, what kind of pipe do you have? Triple wall insulated or single wall?
A thimble or through the ceiling transition comes in many forms. For single wall you'd find two rings that mate with each other, these rings often vented to cool the heat transfer from pipe to thimble.
Insulated pipe will have similar two pc transition, that you can insulate right up to, however the area is sealed so no air transfer. You can use RTV caulk around the pipe in that case to seal where it slides through..............................I think.
What I have in the shop is what amounts to a single wall to triple wall through the ceiling transition. The single wall connects up to the bottom of the transition to a trip. wall "thimble". The top of that thimble is made to fit up to trip. wall pipe.
So, to answer the question...............beats me, depends on what pipe you have and whether it's street legal to seal the gap.
Call the pipe manufacturer
They may OK you to use fire-rated sealant in that gap.
Looks odd to me. The thimbles I'm familiar with are all one unit.
Like David said, you might be able to use a fire rated sealant, but I think you're going to have a hard time making it look good from below (I've never seen it in flat black). You might have better luck applying it, or fire-rated rock wool, from above.
take off the collar
That flange is decorative. You should be able to take it off and see how the chimney connector connects to the chimney. Generally there's a box or cylinder around everything which is rated for contact with combustibles, and you can seal that to the surrounding ceiling with low-temperature caulk or silicone.
You can also use furnace cement on the high-temperature part (do the other joints too), or stove gasket sealant, etc.