Insulation system to use for an insulated attic?
I’m designing and building a house in Houston, TX Zone 2A. I want to insulate the roof line so I have a conditioned attic. For the roof construction, i’m initially planning on using TechShield with an Ice & Water shield and asphalt roof system. I do have some hesitations using spray foam. Interior Air Quality is a priority. Basic questions are as follows.
1. With a vapor barrier on the roof decking should you use a closed cell foam underneath the decking or should you use a batt or blown cellulose for vapor transmission? Will the closed-cell act as another vapor barrier “sandwiching” the roof decking?
2. Can you use a blown cellulose in the roof joists and rigid foam boards to close off the eaves and soffit areas if you avoid spray foam?
3. Is blown cellulose the best insulator for the walls?
4. With all the info available regarding conditioned attics, im a little confused on the best direction in the hot and humid Houston area.
Comments are appreciated.
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