WebClass I – Very low permeability vapor retarders – rated at 0.1 perms or less. Sheet polyethylene (visqueen) or unperforated aluminum foil (FSK) are Class I vapor retarders. Class II – Low permeability vapor retarders – rated greater than 0.1 perms and less than or equal to 1.0 perms. The kraft facing on batts qualify as a Class II vapor retarder. Web3. apr 2009 · At a typical thickness of 5”, open-cell foam is rated from 5 to 10 Perms (dependant on specific product). By definition, a vapor retarder has a Perm rating of 1.0 or …
Exterior rigid foam and vapor concerns in Climate Zone 4
Web3. feb 2024 · For purposes of compliance with Tables R702.7(3) and R702.7(4), spray foam with a maximum permeance of 1.5 perms at the installed thickness applied to the interior … Web28. júl 2024 · EPS - Expanded Polystyrene Foam Insulation Boards: Rated at R4 per inch; EPS foam insulation boards are more permeable to air and moisture than XPS, but it doesn't retain moisture to the same extent because of it's more closed cell structure and it's breathability which lets it dry out. pink white sox fitted
Spray Foam: Open-Cell vs. Closed-Cell Johns Manville
Web29. júl 2024 · R702.7.1 Spray foam plastic insulation for moisture control with Class II and III vapor retarders. ... Sheet polyethylene, nonperforated aluminum foil, or other approved materials with a perm rating of less than or equal to 0.1. II. Kraft-faced fiberglass batts, vapor retarder paint, or other approved materials applied in accordance with the ... WebAssemblies containing spray-applied foam plastic insulation shall be qualified by use of one of the room corner fire tests specified in Section 302.4.1, 302.4.2 or 302.4.3. The testing … Web11. sep 2015 · The proposed roof structure is 12" joists at 24" o.c. Because of the butterfly roof and limitations on venting, we opted to use a flash & batt method to avoid it all together. Per our climate zone we are figuring R-20 -- 3" of closed cell spray foam and R-30 batts making up the remainder of the 12" of structure. stein and co