GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Interior sheathing with outsulation?

travismarttinen | Posted in GBA Pro Help on

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?

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Replies

  1. GBA Editor
    Martin Holladay | | #1

    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.

  2. user-659915 | | #2

    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.

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |