. Therma Sheet provides excellent thermal and moisture protection under metal roofing, stone coated steel and clay tile. The product is very lightweight and easy to install. The... into the attic by super heated roofing materials. Therma Sheet used under your roofing system will help cut your summer air conditioning bills. It greatly reduces attic heat gain making... with a radon mitigation system it can also be used as a radon barrier. Applications it can be used for include lightweight/gypsum concrete pours, wrapping foundation walls, and under...