Traditional underlayment is made of organic building felt. It's good, but now there's something even better to help protect critical areas. GoldShield is a remarkable membrane, composed of a rubberized asphalt material. Its special chemistry makes it extremely flexible for easy installation and top performance, even in extreme weather conditions. Best of all, it offers unique sealing properties that will actually form a protective seal around each nail or fastener so that there won't be any space at all for water to drip through. A self-adhesive backing is protected by a silicone-treated release sheet which is easily removed during application. It is surfaced with a unique treated film to provide a non-slip surface.