This video explains how to incorporate a radiant barrier UNDER certain types of roofing systems. Metal, tile and concrete roofing systems usually have an airspace which will allow a radiant barrier to work. AtticFoil® Radiant Barrier Foil Attic Insulation is placed over the waterproofing layer and then battens are installed. The heat that would normally be absorbed by the roof is now reflected by the radiant barrier. By keeping the heat out, the attic will be cooler and the home will be more comfortable and energy efficient.