Best way to seal off attic above drop ceiling? Plywood and seal, 1 or 2" foamboard?
I am trying to come up with a solution to seal off the attic of this 5800 square foot house. The top attic is two parts: one part that is drywalled (300 sq ft) and other that is not (420 sq ft). It has a drop ceiling and if you move the tiles away you can just push up through the 9 inch fiberglass batts into the attic.
So they technically are heating an additional 700 sq ft of space until I close it off to shrink the envelope to the roof of the third floor. I was originally thinking 2 inch Thermax, then blow an additional 14 inches of cellulose. But Thermax was getting expensive.
Would I be able to just do drywall or 5/8 plywood and spray a coating to give it a vapor barrier? Or can I use 1 inch foam board then seal it and then put down plywood?
What is the most cost-effective and efficient way to close off that attic? (Note* there is fiberglass ductwork up there.)
Posted Wed, 03/19/2014 - 13:49
Edited Wed, 03/19/2014 - 14:12
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