Tongue and Groove
I purchased a bank repo home in Northern Wisconsin in 2018. It has cathedral ceilings with T&G pine applied to the rafters. The builder from what I can find was a sno-bird and traveled south for his winter months. The ceiling cavities have foam chutes and 12″ batt insulation, and the T&G applied directly over both. No plastic, paper or sheetrock vapor barrier was used in the construction of the ceiling. My issue of course is I’m living in the home year around and heating it with LP radiant in floor heat system with a LP forced air backup system. Major heat loss thru the ceiling… I had an Air/door test done and of course it showed all the leaks in the ceiling. The suggestion from the air leak guy was to caulk all the seams of the ceiling from the inside of the home. It seems to me that it could stop the air leaks but at what cost astatically. The ceilings are stained a medium pine color and I’m afraid I’ll see a shiny seam on all the boards from the caulk when done. What’s your advice.? jmstenseth
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Replies
Your best option is to pull out the T+G boards, put up a good air barrier behind them, then reinstall. Chances are that you'll break/damage some of the boards when doing this, so you'll need some new material to replace the damaged ones, painted/stained to match. If you randomly mix these new ones in, small variations in color and tone won't be as noticeable, as you'll get a randomized pattern that will look "right". If you go this route, 1/2" (or thicker) foil faced polyiso works well, but you can also use drywall.
Assuming those vent chutes are properly vented with soffit and ridge vents on the end, the rest of the assembly is probably OK IF you haven't had any moisture issues in the past (in which case you might need to replace some batts and possibly do some mold remediation if it's bad).
I've sometimes thought about painting the ceiling as a sort of air seal process, with the thought that a heavy sprayed-on application would probably wick into the gaps between boards and at least improve the air sealing somewhat. I've never tried this though, and can't say it will really accomplish much -- especially after a few seasons that will likely cause some cracks in the coating.
Bill
I agree with Bill, any attempt to seal between the boards is just going to develop cracks as the boards move with the seasons.
I got a tool called Duckbill for taking decks apart but I find it does a good job on tongue-and-groove too. If the wood isn't old enough to be brittle it can pull the nail head through without damaging the board. If the boards are brittle it can pull them away from the rafter enough that you can get a sawblade in and cut the nail off.
Link is:
https://www.amazon.com/gp/product/B01N6I35UU
JM,
The easiest solution is to leave the boards in place, and simply cover them with new drywall. It won't look the same, but you'll get the performance you want.