PVC Roof “Vinyl” (Polyvinyl Chloride)
PVC Roofing Systems have been installed since the 1960’s and was one of the first single ply materials used in roofing. PVC Roofs come in thicknesses from .036 mil to .090 mil, can only be reinforced (On older non-reinforced PVC roof systems, the entire roof could shatter under cold conditions), and is typically white, tan or gray in color. A PVC membrane installation can be mechanically attached, fully adhered, or ballasted.
Like TPO roof systems, PVC Membrane rolls and flashing membrane are heat welded together, creating the strongest bond available in a roofing system. A PVC Roof installation is heat welded together using computerized hot air equipment that reaches temperatures of around 800 degrees in the seams. For welding the seams on open membrane rolls, an automatic “robotic” welder is used that automatically sets the correct temperature, applies the perfect pressure, and sets the best speed to perfectly weld the two membrane sheets together. For smaller areas, like rooftop units and curbs, a hand-held heat welding gun is used, along with a rubber roller. These smaller detail areas rely heavily on the craftsmanship of the roofing mechanic to achieve the correct temperature, pressure and speed required for a perfect weld.
Benefits of a PVC Roof
PVC Roofing systems have solid strengths. Some Benefits of a PVC Roof are:
- Proven system that has been around for over 50 years.
- Strongest seams available, which is typically the weakest point in a roof system
- Resistant against a variety of chemicals.
- White, Tan and Grey PVC roofs are much cooler than comparable black EPDM roof systems, which is beneficial to HVAC units and other rooftop equipment.
Drawbacks of a PVC Roof
In the roofing industry, PVC roof systems are being overtaken by TPO, because TPO holds many of the same strengths of PVC without many of the drawbacks. PVC system drawbacks include:
- More expensive than TPO Roof systems or EPDM roof systems.
- Weaker puncture resistance than EPDM or TPO.
- Can shatter under cold conditions. On non-reinforced PVC, the entire roof shatters. On reinforced roof systems, the shattering is contained, but still occurs.
- PVC roofs tend to shrink over time, causing the membrane to pull from walls, rooftop units, etc.
- Not environmentally friendly product, due to toxins being created during manufacturing process and during burning of PVC. PVC has been banned in many countries for this reason.
- PVC membrane is not combatable with different PVC manufacturers. The same manufacturer must be used for all patchwork, new rooftop unit installations, expansions, etc.
- Effective welding requires extensive experience. Only the best contractors should be considered for installing a TPO Roofing System.