Tradesman SBS Base is a modified bitumen base ply designed for use in multi-layer modified bitumen roof membrane systems. Tradesman SBS Base consists of a lightweight random fibrous glass mat impregnated and coated with styrene-butadiene-styrene (SBS) modified bitumen. The top and bottom surfaces are covered with a mineral parting agent. SBS Base can be applied with Type IV hot asphalt or compatible cold adhesive to approved substrates.