Environmentally Safe Products Inc.’s Therma Sheet roofing underlayment has been certified by the International Code Council Evaluation Service. The designation means Therma Sheet meets the code requirements of a standalone roofing underlayment for the building industry. Previously, code required roofers to install Therma Sheet over a layer of felt paper or another underlayment. Therma Sheet insulation is constructed of 99 percent pure polished aluminum facings, heat laminated to a closed-cell polyethylene foam core. This patented process makes Therma Sheet a thermal and moisture barrier under metal roofing, stone-coated steel, concrete, clay tile and more.