Reinforced PVC Roofing Membrane

Polyvinyl chloride (PVC) membrane roofing is made up of two layers of flexible PVC surrounding a woven polyester (PET) reinforcing layer, or scrim. Flexible PVC is made up of a variety of additives including plasticizers, pigments, flame retardants, antimicrobial pesticides, fillers, and thermal and ultraviolet stabilizers. PVC roofing membranes are typically sold as sheets ranging from 40 to 96 mils in thickness. Literature from one manufacturer indicated that PVC roofing membranes may include up to a combined 10% pre-consumer and post-consumer recycled content. Depending on the source and type of recycled content, this may introduce additional hazards. Roofing membranes are sold in rolls which are applied over structural decks and additional components like insulation, vapor retarders, and gypsum board. They are attached via mechanical fasteners, site- or factory-applied adhesives, or loose laid with gravel. Membrane seams are heat welded. This CP does not include installation products such as fasteners or adhesives, but characterizes the roofing membrane alone. 

PVC roofing membranes require a plasticizer to make them more flexible. These plasticizers can be liquid or polymeric. This Common Product profile represents products using only liquid plasticizers, which is common for PVC roofing membranes. Much of the product literature surveyed indicated that orthophthalate plasticizers are still common in these products. Modified PVC membranes, sometimes called KEE membranes, include a polymeric plasticizer ketone ethylene ester. These plasticizers are not expected to migrate from the roofing membrane like liquid plasticizers. Such products were beyond the scope of this Common Product profile. 

A historical version of this Common Product is available here: https://pharos.habitablefuture.org/common-products/2214430