Polyvinyl Chloride (PVC) membrane roofing is derived from two simple ingredients: fossil fuel and salt. 

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PVC resin is modified with plasticizers and UV stabilizers, and reinforced with fiberglass non-woven mats or polyester woven scrims, for use as a flexible roofing membrane. PVC is, however, subject to plasticizer migration. (a process by which the plasticizers migrate out of the sheet causing it to become brittle.) Thus, a thicker membrane has a larger reservoir of plasticizer to maintain flexibility over its lifespan.

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