Thermoplastic polyolefin (TPO)

What is TPO? Thermoplastic is a material with a unique ability to be cooled and reheated. The seams of this material are typically heat welded with either solvents or simply hot air. Thermoplastic Olefin are calendared to PVC yet are lamination-based in manufacturing. Two different polymers, polypropylene and ethylene, are forged into sheets with polymer added to backing. They are flame-retardant, UV absorbent and have stronger qualities than most other Thermoplastic membranes. TPO and PVC roofs are the two most commonly used thermoplastic membranes due to their material qualities. TPO is an elastomeric membrane that accepts roofing motion along with the damaging thermal shock. They are resistant against ozone and algae, eco-friendly and safe to setup. It is a single-ply membrane and is usually installed with mechanical fasteners that place down on the edge of the sheet and are secured with the membrane into the roof’s decking. Seam strengths are reportedly three to four times those of EPDM’s adhesive and tape seams. TPO is extremely resistant to tears, impact from hail, and punctures with good flexibility to accommodate for building movement. It comes in standard colors, white, light gray, and black with thicknesses of either 45 or 60 mils. The width of the membrane is varied depending on the manufacture, but they typically start with widths of just under seven feet and 100 feet in length.

The Membrane formulation contains no plasticizers or chlorine, which prevents it from drying out or becoming fragile with each passing year. A TPO membrane comes in a reinforced and non-reinforced finish, and the material is completely recyclable during the production process. Single-ply PVC membranes are very comparable in appearance to TPO.

TPO is often less expensive than PVC, and seems a lot more rigid. TPO membranes also generally forego the need to use “fiber” as an internal puncture barrier.


What is the most appropriate application for this system?

Many hot and dry climates often opt for this material because of extreme concentration of ultraviolet rays constantly beaming down on the roof. Where as with tar-based roofs, they radiate heat inwards since they lack UV-blocking properties. Thermoplastic membranes generally carry UV protection much stronger than conventional roofing systems, keeping the adhesives relatively cooled in comparison to other materials. Also, the application process of thermoplastic membranes is much quicker than conventional roofing materials since they are generally applied to flat roofing systems exclusively.