SBS PolyBase is a modified bitumen membrane featuring a blend of SBS (Styrene-Butadiene-Styrene) rubber polymer and high-quality asphalt reinforced with a strong non-woven polyester mat enhanced with continuous fiberglass yarns. The addition of SBS rubber polymer optimizes the asphalt blend to increase its natural waterproofing properties, adding elongation, elasticity and flexibility to the sheet. The fiberglass reinforced polyester provides strength and stability to the product, yielding a membrane that resists natural forces and other factors on the rooftop. SBS PolyBase is designed specifically as a base layer for use with SBS Modified Bitumen Systems and is ideal for use on both new construction and reroofing projects.