Air barrier using closed-cell spray foam
I am building a house, Zone 4A, with a Cathedral ceiling in the south half of the roof and a loft using trusses in the north half. Exterior insulation on the roof is not possible. The roof will be vented. One builder I interviewed did say he’d apply 1” sheet insulation on the exterior walls. I’d like to use closed cell foam for an inch throughout the interior space to create an air barrier and to begin the insulation process.
If the closed cell is continuously sprayed on the walls, top plate and up the roof rafters [Cathedral portion, across the attic floor in the truss portion] will that be an adequate air barrier? Will doing that tie the walls to the roof as one continuous air barrier?
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