- Install as sheet or laminate to OSB decking (OSB is Oriented Strand Board-now used instead of plywood in many cases)
- Blocks 90%+ of roof deck radiant heat
- Attic should still be ventilated at eaves and ridge
- Check manufacturers warranty. For a while composition shingle companies were afraid of the heat generation back through their product. I think they have eased their concerns lately, but always check.
There needs to be an air space between the roof sheathing and the radiant barrier, there are also spray on barriers. It is possible to retrofit an existing roof by calling your trusted roofing contractor. We use Roofmax in Concord (925) 685-4151 for our roofing needs and Icalled. Yes, they install radiant barriers; but any roofingcontractor knows about radiant barriers. www.builditgreen.org has a green products listing also. I am going to look into this more for my home as well. As my daughter says, "Google it Mom."