Polyethylene as WRB and air barrier – comments?
I’m considering the following wall assembly, from interior to exterior:
vapor permeable interior finishing, gypsum board, wood frame wall with unfaced fiberglass batt insulation (diagonal braces, no wood-panel sheathing), 2″ polyiso with no seam detailing, polyethylene (shingle lapped with sealed seams) transitioning to fully adhered membrane around all envelope intrusions acting as WRB and air barrier, 3″ EPS offset seams, rainscreen with light-weight cladding.
A more expensive alternative i was considering would be to replace the polyethylene with a fully adhered membrane all around, glued to the polyiso, but i would prefer to save on the membrane costs.
I’d love to hear any thought anyone has on this assembly.
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