Maintaining the Air Barrier with a Wood Stove Installation
Evan here, moving forward with my 8×10 tiny cabin in Vermont (zone 6). With the help of this generous community I have created an unvented, 3:12 shed/skillion cathedral roof as follows: Exposed 2×6 rafters, 7/16 sheathing with taped seams, Grace Ice and Water Shield, 3″ polyiso, 5/8 sheathing screwed to rafters, #30 felt underlayment, metal roof.
I am now working to install my heating system, which I hope to be a wood stove. I want to make sure I plan the install correctly given how much time, energy, and money I put into making the ceiling warm and air tight. Ive seen a few threads in the Q&A history about air tight wood stove installs where the poster already had their stove and chimney pipe and were stuck with a certain manufacturer’s recommendations. I do not have my stove or pipe yet so I have a lot of flexibility.
Question: What is the best practice for maintaining the integrity of an unvented roof with a wood stove? I could simply go out of the wall instead of the roof but I would have a similar issue as I have also detailed air barriers at multiple levels in the wall assembly.
Any advice or tips would be great! Thank you – Evan
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Replies
Evan,
Because you need to maintain a gap between the flue and combustable materials, the easiest way to air-seal the intersection is to install a galvanized or stainless steel collar and use high temperature caulking to seal between the two.
Most chimneys manufacturers make cathedral supports that are quite air-tight. You might want to check with whichever chimney supplier you are using before building your own.
Amazing Malcolm thank you for this info I will make sure to do as you advise!
Note that the "high temperature caulking" Malcolm recommends is the red silicone HIGH-TEMPERATURE caulk. I've seen people occasionally confuse that material with the red FIRESTOP caulk which is an intumescent (expands when heated) material use to plug holes in fire barriers.
Both types of caulk are more expensive than the regular stuff.
Bill