If youÂre tearing up the sheathing under the shingles, you can purchase the plywood with the aluminum barrier attached to one side and do both at once.

Having it on the plywood it the best method to apply the radiant barrier.

I have it on the underside of my sheathing, my neighbor with the same shingles does not, we both have full vented soffits and ridge vents. His attic is 30 degrees hotter than mine when the sun is shining.

Thank you! We'll bring it up with the roofers as we are getting quotes!

If you are not replacing the sheathing, you can put foam sheets with the foil on your rafters in your attic. Also be sure to put enough blown in insulation on the floor to equal 12". You can put the cellulose over fiberglass to equal 12"

Please look at DougRye.com
He is the energy expert here in the South.