Single-ply membranes are flexible sheets of compounded synthetic materials that are manufactured in a factory. These materials provide strength, flexibility, and long-lasting durability. The inherent advantages of pre-fabricated sheets are the consistency of the quality of the products that are manufactured, the versatility in their attachment methods, and therefore, their broader applicability. Some of the single-ply membranes in use today are: EPDM, PVC, and TPO.

EPDM is an elastomeric polymer synthesized from ethylene, propylene, and a small amount diene monomer. In its typical form for roofing applications, an EPDM membrane is a cured, or vulcanized, material and is thus classified as a “thermoset”. Simply defined, this means that the polymer's molecular structure is “set” as a result of heating during the manufacturing process. EPDM sheets can be produced in various colors, non-reinforced or reinforced, and range in thickness from 30 – 90 mils. EPDM membranes can be installed using one of three methods: ballasted with large stones, fully adhered with an approved adhesive, and mechanically attached to the roof deck.

PVC (polyvinyl chloride) is produced by the polymerization of vinyl chloride monomer, a gaseous substance resulting from the reaction of ethylene with oxygen and hydrochloric acid. PVC membranes can be non-reinforced or reinforced with glass fibers or polyester fabric and come in thicknesses ranging from 45 – 96 mils. PVC membranes can be installed by mechanically attaching the membrane to the roof deck, fully adhered with an approved adhesive, stone ballasted, and paver ballasted. PVC membranes do not cure after exposure to the elements therefore remains heat weldable throughout life.

TPO (thermoplastic polyolefin) is a blend of polypropylene and ethylene-propylene polymers. TPO's are the “new generation” roofing membranes that combine attributes of two of today's popular flexible single-ply membranes EPDM and PVC. Some of these attributes include long-term weathering resistance, cold weather flexibility, tear resistance, puncture resistance, and chemical resistance. Like PVC membranes, TPO's do not cure after exposure to the elements which allows them to remain heat weldable throughout the life of the membrane. TPO's may or may not be reinforced, produced in various colors, and come in thicknesses ranging from 40 – 100 mils.