Air sealing between rafters
I am getting ready to side a “backyard cottage” with a shed roof in Seattle. The wall and roof assemblies consist of the following…
Unvented Roof – 2×10 rafters filled with fiberglass or cellulose, 5/8″ OSB with taped seams, 2 layers of 2″ polyiso insulation, 1/2″ OSB nail base, ice and water shield, metal roof
Walls – OSB, 1 1/2 ” polyiso with taped seams that will serve as air barrier and WRB, 1/2″ rain screen battens, Hardiboard siding (mostly). I opted not to tape the OSB seams as the polyiso seams are taped to serve as the WRB, and taping both seemed redundant.
I feel good about the air barrier in general, but my question is what is the most efficient and effective way to seal the space between the roof rafters? Cut and cobble polyiso? Spray foam on the inside? Photos attached. Thanks.
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