Wednesday, February 3, 2016

Need help with rafter insulation

Ok to start...I already have blow in insulation.



I live in Kingman, AZ where we don't quite get Phoenix heat, but it still gets damn hot. Usually 10-15 degrees lower than PHX. We get humidity during monsoon season for 2-3 months. Rest of the year is pretty dry other than rain, but then the ambient humidity is minimal.



House is a single story stick home, 2 years old, asphalt 3 tab roof on top of OSB. Quality stucco, with insulated outter walls, 3 natural vents in attic. Pretty simple construction. All things considered it's pretty efficient. With somewhat conservative settings, september 2014 I used 512 Kwatts. (was staying with girlfriend a lot this last summer so had AC minimized).



Ok, onto rafter insulation. Would pushing fiberglass batting between the rafters be a proper way to keep roof heat from entering the attic? I see online where many people sprayfoam the attic, or use white styrofoam insulation to create a gap that vents to???? My problem is the only access is the hole in the hallway of the house. It's big enough to crawl into, but not really big enough for sheets of that white styrofoam. And after reading some horror stories of spray in foam (chemical smells)....I'll just pass thanks.



As for the batting, I guess I'm worried about either 1. humidity getting between the batting and OSB and molding....2. Too much heat building up and destroying the OSB/Roof/etc.



Thanks in advance

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