# Fiber faced Poly Iso board vapor barrier



## CDiablo (Oct 29, 2013)

Excuse me, I mean felt faced not fiber.


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## Gary in WA (Mar 11, 2009)

Welcome to the forums!

The fiberglass faced would stop any moisture trying to exit the rooms below to the attic space where it would be removed by ventilation. I would use something more permeable, (over the <1 perm) especially if you already have a vapor barrier/retarder poly/craft-faced next to the ceiling drywall/plaster. http://www.menards.com/main/buildin...decking-insulation-board/p-1485632-c-5779.htm

http://www.google.com/url?sa=t&rct=...AlLK4qHT75vjXLA&bvm=bv.55819444,d.cGE&cad=rja

Air seal the attic first, before all else; http://www.google.com/url?sa=t&sour...sg=AFQjCNHwd56o0AxLi8-V03E5cMUmwWATQw&cad=rja

Gary


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