EPDM

A factory-manufactured polymeric waterproofing sheet, typically EPDM, TPO or PVC, installed in a single layer and joined at laps by welding, adhesive or tape. Single-ply systems may be mechanically fastened, fully adhered or ballasted, and are widely used on flat and low-pitched roofs.

Thermoplastic polyolefin, a polymer blend based on polypropylene and ethylene propylene rubber, used as a heat-weldable single-ply roofing membrane. Being thermoplastic, seams are joined by hot-air welding rather than adhesive, and the material contains no plasticisers. Related grades are used for automotive interior and exterior components.

A single-ply roofing and waterproofing sheet based on plasticised polyvinyl chloride, usually reinforced with a polyester or glass fibre scrim and joined by hot-air welded seams. PVC membranes are flexible and easy to detail, though plasticiser migration and incompatibility with bitumen and polystyrene must be addressed in design, typically with separation layers.