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PVC roofing membranes must have a property added to them to make them flexible. PVC membranes typically have liquid plasticizers added to give them their extreme flexibility. The challenge with these liquid plasticizers is that they eventually migrate to the surface of the membrane causing it to become brittle. DuPont solved this problem by developing a method to soften PVC material without the use of those liquid plasticizers. They produced a material called Elvaloy® KEE that gives PVC flexibility without plasticizer migration. One roofing manufacturer, in particular, has taken advantage of this and uses over 50% KEE in its roofing membrane completely eliminating the need for liquid plasticizers.


In addition to overcoming the challenge of plasticizer migration, the addition of KEE greatly increases the membrane’s durability and longevity. It is able to resist harsh chemicals, acid rain, industrial pollutants, oils, fats, and jet fuel unlike any other roofing system on the market today. Its weather resistance is also unparalleled being able to withstand large amounts of hail. Many high quality KEE roofs have been installed in North Texas over 30 years ago and are still in service today.


There is only one manufacturer that meets ASTM D 6754-10 standard for KEE roofing—FiberTite. G4 Roofs is a Factory Authorized FiberTite Installer.

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