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Community and Q&A

Does Water-Damaged Plywood work as an air barrier?

joejoemiller | Posted in General Questions on

We’re building a house that has a flat roof.  Due to a variety of issues in the construction process the flat roof has been rained on repeatedly; it is not possible to prevent the roof from getting rained on.  The plywood is now in various states of decay.  We replaced the absolute worst bits, the pieces where the plywood disintegrated.  The rest of it is at best roughed up, at worst it’s taken on a permanently wavy top layer that bulges with each successive rain.  

We’ve taped the seams of the plywood in order to create an air barrier because the flat roof membrane will include building elements that are not part of the enclosed building envelope.  Do we need to do more to make this water damaged plywood work as an air barrier, as planned?

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  1. Expert Member


    It sounds like parts of the plywood have decayed to the p0int where it might not function as either an air-barrier, or as a structural component of your roof system.

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