# Vapor Barrier on elevated 4 season room



## AGWhitehouse (Jul 1, 2011)

Vapor barriers provide no R-value (insulative) gains. They strictly control the migration of moisture vapors through a system. I wouldn't worry about adding one in, if temperature is your concern, then the soffit demo and spray foam is your best bet.


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## Gary in WA (Mar 11, 2009)

I agree with AGW, above. Remove the plywood and aluminum as they are vapor retarders. You already have one vapor retarder (plywood) next to the heated side. The joist bottoms are cold giving you a heat sink and cold floors; http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces/

Gary


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## Indyc0lt (Sep 14, 2011)

Great info. Thanks


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