Parabase is an asphalt coated fiberglass base sheet. It consists of a lightweight random fibrous glass mat impregnated and coated with a specially formulated, high-quality, oxidized asphalt. These base plies are approved for use as a protection course in the hot applied rubberized asphalt PA-750 System. Parabase is typically mechanically attached, but some variants can also be applied with cold adhesive or hot asphalt in certain systems. All Parabase base sheets meet ASTM D4601, Type II Standard.

Parabase variants include Parabase FS, which has a polyolefin film backing. Parabase Plus is impregnated and coated with an SBS-modified bitumen blend and can be applied with hot asphalt or cold adhesive. Parabase Plus P is impregnated and coated with SBS-modified bitumen, with a top surface that has a proprietary Syntan^® acrylic coating designed to enhance adhesion of Siplast self-adhesive SBS-modified bitumen sheets.

Compatible substrates include: Concrete, wood, metal