When rain and snow hit, StormShield® ice and water protector acts as a secondary barrier to help protect against wind-driven rain and unwanted moisture that can penetrate the shingle layer, causing leaks or ice dams. Made of non-woven glass fiber mat, this modified bitumen roll is easy to install with self-adhesive backing for watertight sealing in critical areas. You can also use it as flashing membrane around dormers, vent stacks, skylights, or even doors and windows.