Single-ply roofing systems are just that, a single ply of a roofing material made from several types of polymer plastics and rubbers.
Ethylene Propylene Diene Monomer is manufactured into large sheets for application to insulation on a roof. The material can be loose laid and ballasted with rock or pavers to hold the membrane in place. It also can be fully or partially adhered as well. Seams and the membrane are adhered with contact adhesives, with seams sometimes sealed with a sealant. Toppings may or may not be required by the manufacturer in many cases. This product is available in black.
Polyvinyl Chloride Sheets are manufactured into rolls, and typically mechanically fastened to a roof deck assembly. Screws and plates are used to hold the roof membrane to the roof assembly. Seams are heat-welded together, and sometimes sealed with a lap sealant. PVC membranes are reinforced with a fabric scrim, and available in tan and white colors. A topping material may not be required on this membrane.
TerPolymer Olefins typically are fleece-backed sheet membranes that are adhered with adhesives to insulation. These products typically are white in color, and may be reinforced. There may or may not be a topping system used on these systems.