I would like to install Roxul(stone wool) insulation under subfloor. I am located in NY, Long Island. Roxul will be installed in a vented crawlspace. Since Roxul is not kraft-paper-faced like fiberglass, do I have to install vapor barrier between batts and subfloor? If I do, then what kind: plastic(mil?), tar paper else? Thanks!
True, good advice! See if they accept the sub-floor sheathing as a vapor retarder and if able to cover it with a housewrap to stop air from wind-washing and degrading the R-value.
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