Will I rot out my plywood roof decking if I condition my attic space?
Will I rot out my plywood roof decking if I condition my attic space? I have a standing-seam metal roof with 15 lb. felt paper as an underlayment. I am in a coastal climate on the Puget sound in WA state (marine zone 4).
I am considering a conditioned attic space in my home that I am remodeling. We want to use the space for storage and a play space for the kids. I am certain the interior space would have sufficient ventilation from the HRV.
What I am concerned about is rotting out the roof decking since I have an insufficient moisture barrier (greater than 1 perm) under the metal roofing. The metal roof is well constructed and should prevent vapor drive (as I understand it my metal roof should not be as susceptible to inward vapor drive as would other roofing materials) but should I be concerned about condensation? The metal roof is not an air barrier and I am pretty certain the tarpaper is not perfectly applied and covering the decking underneath the metal roof.
Posted Tue, 02/11/2014 - 14:04
Edited Tue, 02/11/2014 - 14:14
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