Air Sealing Wood Paneling
I’m in climate zone 6 (New Hampshire) and am close to finishing the framing of a 24×32 garage apartment with the living space above the garage. The total living area is roughly 750 sq. ft.
I prefer the look of wood paneling for the living area for both the walls and ceiling (garage will still be drywalled), but I’m now suddenly concerned about being able to adequately air seal the ceiling. My insulation approach, up to this point, is 2 inches of polyiso on the exterior, foam air sealing the top plates in the living area, mineral wool insulation in the 2×6 cavities and loose fiberglass insulation in the attic.
Part of my motivation for wood paneling is that it’s also less expensive that drywalling the living area, but I feel like I may working against my goals of tight air sealing with the introduction of the wood paneling and that mitigating any air sealing issues may offset the cost savings and may introduce added fussiness.
Am I right to be concerned or are there simple solutions to ensuring proper air sealing with the wood paneling?
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The air-sealing of wood paneling is done by including a substrate that can be made air-tight. That is usually drywall, sheet goods like plywood or OSB, or a membrane -either p0ly, or a variable perm one.
Thanks for the reply Malcom. That's kind of what I figured would be the case. I would imagine that the drywall would, at a minimum, need to be taped, if not also a skim coat.
What are you doing with the apartment floor, garage ceiling with regard to insulation?
If your main air barrier is at the roof deck, the only thing you need on the warm side is a class III vapor retarder. Permeability of most plywood falls into this range, so you a probably ok to simply nail the sheets up. I would still tape over the seams under the battens with a narrow flex tape (3m8067 is available in 2") as a backup air barrier.
It also wouldn't hurt to do a blower test before doing any interior insulation or paneling. This would let you see if your roof is tight and also how good is the separation from the garage. Fixing major leaks at that stage is pretty simple job. An official blower door is the best but you can do a decent job with a box fan taped into a window and some smoke sticks.