Insulation at Attic Floor vs. Roof Line
My 15×30 cabin has R15 (3 inches of foam) on the exterior. This continues up to the attic. I put in raised heels to allow for venting without constricting the airflow around the top plates.
I’m deciding now whether I want to condition the space (rafters) or insulate the attic floor (cj’s).
I don’t plan on storing anything in this attic ever. The only mechanical or HVAC equipment that I plan on ever having will not be in this area. I do have the plumbing vent passing though.
If I insulated the floor, I wondered if I could block off the undersides of the rafters to allow the venting to go from one end of the roof to another without creating a breeze in the main attic space. Of course, there would be a vapor barrier from the house.
I’m planning on using salvage iso rigid foam.The floor is likely a much easier job and I won’t have to heat the attic.
Is there anything I’m missing?
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