If I install Kraft faced insulation on inside perimeter walls. Does the paper offer a vapor barrier too, or should I also install poly over it?
Kraft paper is an excellent vapor barrier by itself. Covering the paper with poly would be considered a “double” vapor barrier, this would cause serious moisture issues within the wall. Your most effective insulating practice will be to use either Kraft faced material or unfaced fiberglass with the poly.
Related Questions
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