Single-Ply Membrane
Single-Ply Membrane
Single-ply roofing membranes have steadily grown in popularity over the past 30 years, and due to their flexibility, relative ease of installation, and competitive price, it’s no wonder that building owners and facilities professionals are interested in this product. One of the benefits to single-ply membranes is their production - they are manufactured in a factory to strict, quality control requirements. This consistency in the quality of the products is undeniably one of its strongest selling points.
As single-ply membranes were gaining market share in the United States, concerns for the environment and an emphasis on energy conservation became important topics. Single-ply membranes offered a solution. Light-colored, reflective roof surfaces could offer building occupants a significant reduction in energy use, points toward a U.S. Green Building Council LEED™ building certification, as well as the potential to downsize HVAC equipment. Additionally, single-ply membranes offer a lightweight solution that can accommodate the sometimes unconventional roof designs of modern architecture.
Single-ply roofs can be generally grouped into two categories, thermosets and thermoplastics. Thermosets must be applied with an adhesive, whereas thermoplastics can be hot-welded together.
EPDM membranes are the most commonly used thermoset and are known for their long-term weathering ability, and perform well even when subjected to fluctuations in temperature, ultraviolet rays, and ozone. The membranes are available in both unreinforced and reinforced, the latter of which increases resistance to tearing. EPDM is available in thicknesses ranging from 30 mils to 90 mils, and it’s offered in extra wide sheets of 50’ by 100’ that may be desirable especially for very large roofs.
Hypalon is another thermoset that is actually manufactured as a thermoplastic. Although hypalon is heat sealed at the seams, as it cures over time it becomes unweldable with age, making it a thermoset.
Thermoplastic materials are distinguished from thermoset materials in that there is no chemical crosslinking. These membranes can be repeatedly softened by heating or hardened when cooled. Because of the materials' chemical nature, thermoplastic membranes typically are seamed by heat welding with hot air or solvent welding. PVC and TPO are two of the most commonly installed thermoplastic single-ply membranes.
PVC sheets are produced by calendaring, spread coating or extruding, and typically are reinforced with polyester or glass-fiber mats or scrim. PVC sheets contain plasticizers and stabilizers, as well as other additives to impart flexibility and achieve other desired physical properties. Some membranes are available with nonwoven fleece backing adhered to the underside of a sheet. PVC membranes are available in a variety of colors and range in thickness from 45 mils to 90 mils.
TPO sheets are a blend of polypropylene and ethylene propylene polymers and usually are reinforced with polyester. TPO sheets contain colorant, flame retardants, UV absorbers and other proprietary substances to achieve desired physical properties. TPO membranes are commonly white or black and range in thickness from 40 mils to 100 mils.
A.D. Willis Company is a National Roofing Contractors Association (NRCA) “Authorized Fabricator” of edge-metal roof flashings for single-ply roof systems, and we can provide you with products that are designed and installed in accordance with the ANSI/SPRI ES-1 standards. These standards are already a requirement in several states including Texas, and it’s just a matter of time before they’re required nation-wide.
As with any roof, the ultimate life and durability of the roof is directly related to the quality of the initial installation. A.D. Willis Company has been named a Firestone Master Contractor for our consistent excellence in commercial roofing installations.
