# Thermal barrier on tongue & groove walls



## Bud9051 (Nov 11, 2015)

Hi Adele and welcome to the forum.
A couple of thoughts. Although T&G looks great it leaks air like mad. Using a flexible plastic behind it does not serve as a good air barrier. What you should have is what you excluded, the drywall.

In the ceiling I'm not sure what the intumescent paint costs, but I suspect similar to a layer of drywall. It's been a while since I priced it. If you go that route be sure local code approves and your insurance company.

As for using all closed cell on the ceiling ($$$) that would require at least 2 applications, maybe 3 to get the 7 or 8 inches depth. You are looking for a minimum of r-49 I believe, might be more.

As for dense pack meeting the thermal barrier the mfg should have that information, but I'm not optimistic.

Let's see if others have some input.

Bud

PS, are you having a set of drawings drawn up?


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## AdeleS (Jul 19, 2018)

Bud, Thanks for the response! I was waiting to get others opinions but this forum is like everything else I'm finding...no one can answer my question. I have the product specs and it doesn't reference this application.

Oh well...back to the drawing board...I hate to apply drywall all over just to cover it with ship lap and tongue and groove...that to me seems like a lot of $$$$ and waisted effort, although I would definitely appreciate it if I ever had a fire!


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## Bud9051 (Nov 11, 2015)

Not sure what your local building department requires but many want to see a stamped set of drawings from an engineer of architect. That shifts the design responsibility over to the person who designs your home. I have worked with a few and they are the ones who need to stay up on local requirements and new energy methods.

As for leaving out the drywall that is difficult as it serves as the thermal barrier and as a rigid air barrier. Installed under the T&G it wouldn't need the final finish, possibly just a single layer of joint compound for the tape but no finish work or paint.

Been a while since I looked at this article but it mentions some energy efficient folks in southern Maine. May have some leads for you.
http://www.greenbuildingadvisor.com...ing-energy-smart-designers-and-builders-maine

Bud


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