Manufacturer offers clarification
I am writing to you in response to "Thermoplastics 101," June issue. Specifically, I would like to address the incorrect information about PVC membranes that was published.
PVC membranes are known for their flexibility and heat-welding properties. Although available in a wide variety of colors, white membranes most commonly are used because of their superior reflectivity. PVC and TPO membranes typically are reinforced with polyester scrim or fiberglass mats and can be mechanically attached, adhered or induction-welded to roof decks. The process of heat welding only is meant for seaming two membrane sheets together—not to attach it to the building as the article implies.
PVC and TPO membranes commonly are used in low-slope applications and range in thickness from 40-80 mils. Comparing these materials as an alternative option to asphalt shingles, typically used in steep-slope roofing projects, is inaccurate and misleading as is the mention of the need to use primer and coatings during maintenance. Although coatings are an option for protecting and prolonging the life cycle of thermoplastic membranes, they are not a required maintenance expense as the article indicates.