TPO (Thermoplastic-Polyolefin) – TPO is a relatively newly developed (early 1990’s) low-slope roofing material made from polyethylene/polypropylene/ethylene-propylene rubber polymers reinforced with fabrics or fibers. TPO is very similar in look and nature to PVC. Because of thermoplastic nature, seams can be heat-welded.
Good UV/heat resistance. May be more economical than PVC but with a shorter warranty of often 10-15 for a standard system. TPO roofs have features similar to thermosetting membranes, but being thermoplastic, they can be heat welded. TPO Roofs have excellent UV, chemical exposure, and ozone resistance. Because of it’s durability, performance, and cost, TPO roofs are one of the fastest growing in the last 5-10 years. The market share has become as much as 20-40% of installed commercial roofs, depending on the region. TPO has some of the most stringest ASTM standards of all the current flat roofing materials. Different TPO producers make different chemical formulas, but they all utilize the same general formula. One of the primary chemical differences between TPO from PVC, is TPO has natural elasticity and flexibility while PVC requires chemical plasticizers to achieve the same.These plasticizers can break down and attract mold and microbes which attach themselves to the roof turning it a darker color over time reducing the inherent reflectivity. Also, as these plasticizers break down the roof returns to it’s more brittle natural state.
TPOmaterial itself is often 10-20% more economical than PVC so not only do many choose it because it can be less expensive, but also because valid data exists that TPO can outlast PVC slightly.