Tradesman SBS Torch Base is a torch grade modified bitumen base ply designed for use in multi-layer modified bitumen roof membrane systems. SBS Torch Base consists of a lightweight random fibrous glass mat impregnated and coated with styrene-butadiene-styrene (SBS) modified bitumen. The top surface is covered with a mineral parting agent, and the back surface is covered with a polyolefin burn-off film.