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vapor barrier on closed cell sprayfoam Post New Topic | Post Reply
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waynr johnson
Posted: Jul 31, 2007 08:14 AM
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vapor barrier on closed cell sprayfoam
I have a 8 inch wood foundation (new construction) and have sprayed 3 inches of closed cell poly. The foam company said I should not put a vapor barrier(plastic) on the interier walls. The local inspector said I need a vapor barrier even with the closed cell poly.The home is in Minnesota. What is the correct solution? |
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Posted: Jul 31, 2007 11:18 AM
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educate the inspector. |
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mason
Posted: Aug 01, 2007 07:54 AM
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Vapor barriers are not required with closed cell foam in all climate areas of the US according to the 2003 and 2006 IBC and IRC codes. Closed cell sprayfoam installed at a 3 inch thickness has a perm rating of less than 1.0 which is described in the codes as a vapor retarder. In the 2007 new supplement, 3 types of vapor retarders are introduced, closed cell sprayfoam would be typed as a class II vapor retarder according to the new codes and again does not require an additional vapor retarder in all climate areas in the US. |
