Single-Ply Roofs: TPO, PVC, EPDM

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TPO, PVC and EPDM are the most popular of the single-ply roof category. These roofs consist of a single layer of membrane which may be fully adhered or mechanically fastened to the roof deck.

 

TPO

ThermoPlastic Olefin is highly resistant to UV rays and is becoming increasing common in roofing, especially in warmer climates. It may be applied on low-slope or steep-slope roofs, and can even have strips applied which give it the appearance of a standing-seam metal roof at a lower cost than metal. TPO is available in a wide variety of colors, including highly-reflective light colors eligible for LEED points and EnergyStar credits.

 

When mechanically fastened, TPO membranes have a tendency to "flutter" in high wind situations. Fully adhered systems can meet high wind uplift requirements and exhibit virtually no flutter. Seams are always heat-welded to form a watertight seal.

 

PVC

Polyvinyl Chloride roof membrane consists of two layers of PVC with a reinforcing scrim sandwiched in the middle. Like TPO, PVC roofs have heat-welded seams which make them exceptionally watertight. While PVC is available with a reflective finish for energy-efficiency, some environmental groups express concern over the chemicals used and released during PVC production.

 

TPO has recently surpassed PVC in terms of popularity, however PVC has a longer track-record as a product which has stood the test of time longer than TPO.

 

EPDM

Ethylene propylene diene terpolymer is a rubbery singly-ply roof membrane traditionally black in color, although white EPDM is available. It is resistant to temperature extremes, and exhibits the least brittleness of the common single-ply membranes in freezing temperatures.