Single Ply roofing systems are just that, a single ply of a roofing material made from several types of polymer plastics and rubbers. The Single ply roof membranes are ballasted, mechanically attached or adhered to insulation or other substrates. Single ply materials provide one ply of material to protect the building instead of the multiple layers in a built up or modified bitumen roof membrane. Single ply membranes include those products made from EPDM, PVC, TPO and other formulations.
EPDM (Ethylene Propylene Diene Monomer)
EPDM is a rubber material that is supplied in large sheets for application on a roof. The material can be loose laid and ballasted with round, river washed rock or pavers to hold the membrane in place. The EPDM roofing membrane can also be adhered as well. Seams and the membrane are adhered with contact adhesives, with seams sometimes treated at the edges with a sealant. Toppings such as ballast or a reflective/protective coating may or may not be required by the manufacturer. This product is available in black mostly.
PVC (Polyvinyl Chloride)
PVC roof membrane materials are suppliedin rolls, and typically mechanically fastened to a roof deck assembly. Long screws and screw plates (large washers) 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.
TPO (Thermoplastic Polyolefin)
TPO roof membranes are typically fleece backed membranes that are adhered with adhesives to insulation. These products are typically white in color, and may be reinforced. There may or may not be a topping system of gravel, ballast or a reflective coating required by the manufacturer on these systems.