Two types of single-ply membranes are most popular and fit with our high quality standards. Here are the differences between the two and what applications each is best suited to:
1. Thermoplastic Polyolefin (TPO) Membranes
TPO is a polypropylene-based plastic and ethylene/propylene rubber material that is similar to PVC. By blending plastic and rubber, manufacturers found they could make an extremely durable, yet flexible, membrane material.
TPO accounts for more than 40 percent of the installed square feet of roofing membrane in the U.S. for the past 7 years. It has become popular because of its ability to resist ultraviolet (UV) rays from the sun, ozone and environmental chemicals. Other benefits include:
* Heat weldable. Using a heat weld prevents seams that let water in. * White color. White is well-known to reflect up to 90 percent of the sun’s rays and keep a building cooler.
* Easy to repair. Damage is limited and does not usually require whole-roof replacement.
* Flexibility. The membrane conforms with any building movement, which is especially useful in tall commercial structures.
In the early 1990s, when TPO was first introduced to the U.S. market, installation guidelines were not as informative and few installers were familiar with the material. That resulted in a lot of early failures and some negative feedback about TPO. But 20 years later, with installers being better educated and ASTM standards more complete, TPO is successfully used in many long-lasting commercial roofs.
2. Ethylene Propylene Diene Terpolymer (EPDM) Membranes
EPDM roofing membranes are rubber-based and made from a blend of ethylene and propylene. They first became popular in the 1970s and have held up well since the first installations. Over time, roofing experts found better ways to seal the seams, moving from liquid adhesives to seam tapes. EPDM roofs account for about 35 percent of the single-ply roofing membrane market and are first and foremost very durable. Some manufacturers offer up to 30 year warranties on their EPDM products, and warranties are available that cover punctures as well as weather damage from wind and hail.
Other benefits of EPDM include:
* Excellent performance in very cold temperatures; does not become brittle like a
material with plastic can.
* Resistant to UV radiation.
* Color options. EPDM is available in white for environmental “cool” roofs or in black.
If you are considering either TPO or EPDM, note that each manufacturer makes a slightly different blend and uses slightly different stabilizers, so the different brands are not interchangeable. Contact us to learn more about which products are best suited for your commercial roof.