# Air Sealing Subfloor Joist Space - Foam Board?



## Windows on Wash (Aug 30, 2011)

Rigid foam blockers, spray foam and seal edges, cover with some fiberglass.

The plywood servers as your thermal barrier (although you really only require an ignition barrier in this case) and the fiberglass covering the foam will serve as your ignition barrier.

Get the foam tucked right to the edge of the warm wall and seal it there.


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## masonbrown (Nov 7, 2011)

Thanks, that makes sense!

-Mason


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