If we use spray foam on the inside of our attic, should we also use rigid foam on the roof?
If we use spray foam on the inside of our attic, should we also use rigid foam on the roof? This is being built in Upper MI.
We had an estimate for spray foam and along with spray foam. The company states it would then put 1" rigid foam on the outside of the roof. Is this normal practice, as I thought you insulate one side, not both? It is an A-frame with cathedral ceilings.
Must be vented by code, insulated to r-49 on roof, R21 in walls. spray foam was to 39 with 1 inch rigid foam on exterior roof. We are planning on putting 4 inches of rigid foam on outside walls.
Posted Jan 1, 2013 8:07 AM ET
Edited Jan 1, 2013 12:39 PM ET
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