We live in Dallas, and the summers are hot. When the temperature is 102 outside, the attic is above 116 degrees. We want to put in a radiant barrier. Why did the Austin house have insulation in the rafters, did it have a radiant barrier between the insulation and roof? Regarding radiant barrier's a friend told me that I could not spray it in the the summer because it is too hot. I plan to do it at night when it is cooler. Is it true that I cannot spray it in in the summer, is there a heat maximum to consider? How much better is the aluminum foil radiant barrier? These questions all pertain to a house that is already built.