Paradiene 20 TS is a uniquely designed, high performance, semi-adhered, modified bitumen base ply designed for use in homogeneous multi-layer modified bitumen roof membrane systems. Paradiene 20 TS consists of a lightweight random fibrous glass mat impregnated and coated with an elastomeric styrene-butadiene-styrene (SBS) modified bitumen. The unique back surface design consists of factory applied, heat activated adhesive stripes combined with a proprietary acrylic coating between the stripes, which provides for uniform bonding of 50% of the total surface area of the sheet.