The perfect bathroom wall?
Although I’ve not tried it, what I’ve read about exterior rigid foam sounds very winning. I’m now about to renovate for the first time and am starting with the bathroom. I’m also likely to reside the house at about the same time which seems to afford me a great opportunity to switch to exterior rigid foam. I’m also thinking of doing this because currently the framing of that part of my house doesn’t fully cover the foundation cinder blocks leaving a point of entry for rain in to my foundation wall. 2″ (or 3″) or rigid foam would allow the exterior edge house to be flush with the exterior edge of the foundation there. I’m currently thinking of making that half foil faced polyiso and half XPS.
Anyway, as I begin the planning of this, I recall that thick rigid foam can act a a vapor barrier… especially if foil-faced. At the same time the bathroom behind this wall, and three sides of the tiled bath/shower immediately behind this wall, is likely to be relatively humid at times and result in moisture entering the wall space. Certainly we’ll have some sort of barrier on the inside to prevent this, right? But then it sounds like we’ll be sandwiching the wall between vapor barriers which I understand to have very poor drying behavior.
I’m sure many of you have already solved this many times. How do I need to adjust my thinking?
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