Sheet metal over interior studs: Mold issue?
I’m a homeowner / GC who’s building a custom home. We’re using 1 1/2″ Roxul for exterior insulation, 1″ closed cell foam on the interior seathing, and cellulose in the remaining 2 x 6 stud cavities.
I[‘m running into one problem though. There’s a few large PVC pipes in the exterior cavities ( see pic ), and few professionals have recommended covering these areas with sheet metal. Doing so will protect the pipe from future nails punctures. However, if the entire stud cavity is covered in sheet metal, and then drywall, will that create a potential mold problem? I say this because there’d be two vapor barriers. One being the closed cell foam and the other being the sheet metal.
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Replies
Ryan,
The best solution is to avoid routing PVC pipes in exterior walls. (Too late for that one.)
The second best solution -- one you can use -- is to furr out the wall (make it deeper) in order to provide enough room to avoid the nail-piercing problem.
The third best solution is to provide a steel protection plate, as your builder suggests. I wouldn't worry about condensation. The 1 inch of closed cell spray foam will prevent inward vapor drive.