I have a guy who wants me to spray the underside of the sheathing in his condo attic with something called "Radiance e-0.25 Attic Barrier". I have never heard of it, but it looks like neat stuff. It is a metallic silver finish that blocks the radiant heat. It looks pretty straightforward to apply, but since I have never seen it, I'm a little apprehensive. Will it cause some weird moisture problem and result in thousands of dollars of damage to the roof? Will the odor make everybody in the condo ill? Will my sprayer explode? If this stuff is so great, how come nobody else is using it?