Adding foam board to ceiling rafters?
The rafters in my ceiling are only 2 x 6. Is it acceptable to lay polyiso sheets across the top of the rafters, or should I be concerned about the foam acting as a second vapor barrier? The fiberglass batts have a kraft liner facing the sheet rock.
If the answer to the above is yes, can I place the foam in between the rafters against the sheet rock under the fiberglass batts?
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