The Asphalt Saturated Organic Felts are manufactured from premium quality Organic mat and saturated with high-grade asphalt. Asphalt Saturated Organic Felts are designed as an underlayment product to be applied over the roof deck prior to the installation of asphalt shingles. Install Asphalt Saturated Organic Felts as a secondary barrier to moisture caused by wind-driven rain and ice damming.