Through my years as a contractor, I’ve seen the industry standard for best roofing practices evolve when it comes to “flat roofs,” which are almost level and designed to drain. When I started, 3 and 4 ply felt sealed with hot asphalt were the standards, and before that coal tar in lieu of asphalt. If you don’t believe it was a messy business, see the photo to the left. These days, most of the roofs we build are Thermoplastic Polyolefin or “TPO” single-ply roofing membranes.
Makeup: TPO is comprised of a reinforcing scrim with 2 layers of polymer blends, making it light and malleable.
Installation: TPO installation uses a heat welding technique. Specialized welding machines are used to heat the membrane, allowing the polymers to melt and join together. The majority of TPO roofs are screwed down with plates and screws to a metal deck or adhered with a bonding adhesive to the insulation. Rhino Bond, a new system, uses special plates that allow an induction weld to join the membrane to the plate. Rhino Bond technology was designed to speed up the roofing process even further while meeting wind speed requirements.
Cost: Ease of installation and low material prices translate to a more cost-effective system.
To me, it’s fair to say that TPO has changed the roofing industry. As demand for heat-reflective and energy efficient roofing systems increases, TPO provides solid resistance to ultraviolet, ozone and chemical exposure. TPO is much cleaner and faster than its predecessors. Installation only requires one layer of material, whereas built-up roofing may have required four. For us, using TPO roofing been an all-around win. But stay tuned…Just like with the felt roofs, TPO will have a successor.
