Cut and cobble eps foam
First I just want to say GBA is awesome and I appreciate all the info .my question is I’m in east Tennessee and I am going to cut and cobble 1 inch polypro eps foam board between the studs with a gap between the foam and osb and gap between foam and drywall with no other insulation it will be heated and cooled do you forsee any vapor drive problems or any other problems that may arise.
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There are wall assemblies that are generally safe, and wall assemblies that are generally unsafe. The space between these two loose categories is a grand canyon of choices.
How did you develop this unusual assembly? Knowing what materials you reviewed and your goals will help people provide more targeted feedback.
The foam thickness you've specified won't meet energy codes anywhere I can think of, and generally the goal is to create fewer areas for air to circulate rather than more (with a few special exceptions, none of which cover your two circulation areas inside the wall cavity).
I got the foam board for free and as for the air space I'm not really worried about r value at the moment I'm more worried about condensation and vapor drive so I figured I'd keep the poly away from the osb for more air drying and the poly away from the drywall for a little better r value and in case moisture did bead it wouldn't bead onto the drywall
My main concern is moisture problems any input is appreciated