Interior vapor retarder?
I’ve got a “tiny house” on wheels I’m finishing up, 10×25 feet. I’m just completing the insulation and trying to decide what to do about an interior vapor retarder, if any at all.
I was looking at membrain but reading some threads here tonight, I’m wondering if it’s really necessary or desirable. I know not to use plastic. I do have some extra jumbo tex (asphalt impregnated kraft paper), but it would stink a while til I got my walls up, which will be months away still. Don’t know how healthy breathing asphalt would be. 😛
My exterior walls are wood clapboard, double layered jumbotex, and osb.
Inside walls will be tongue and groove pine or hemlock, 1/2″ or 5/8″ thick.
My insulation is roxul (rock wool) in 3.5″ studs.
Here’s what I’m thinking:
My roxul is pretty dense, I heat with wood, and I have no shower nor do I make much moisture in the house with cooking or anything, so I wonder if the tongue and groove would suffice to keep the insulation dry.
Would I still be at risk of condensation where the insulatio meets the osb? It just seems like it’s going to be so dry in here in winter that it shouldn’t be an issue. Right now on a damp day I’ve got 40% humidity at 67 degrees.
Thanks for any advice!
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