Interior sheathing with outsulation?
I am designing and building a tiny house on wheels (in climate zone 6) and the wall assembly I have come up with is a little bit unconventional. I would like to use the PERSIST method, but due to size limitations this is not possible. The wall section I have come up with is a little like PERSIST though:
From interior to exterior:
-7/16” OSB (sheathing & interior finish – applied using caulk)
-2×4 wood studs @ 24” o/c filled with 3-1/2” XPS
-3” XPS over the studs
-Solitex MENTO 1000 WRB (38 perms) -taped continuous air barrier
-vertical ¾” furring strips
-open joint timber cladding
I have never seen this wall assembly used, and was wondering if there could be any issues with moisture, fire, etc. My thoughts are that the wall can breathe to both directions and the structure is fully contained on the warm side of the insulation. Has anyone had any experience with a similar wall assembly? Or does anyone think that this assembly won’t perform well?
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Replies
Travis,
Sounds fine to me. When you install the rigid foam between the studs, make sure that you seal the perimeter of each piece of foam with caulk or canned spray foam.
The OSB is going to be outgassing and pretty stinky for a year or two. You might be better off with plywood. On a tiny house the cost premium will not be great.