Roofing systems in general have evolved greatly over time, becoming more efficient in terms of heating, cooling and maintenance as well as becoming increasingly efficient in terms of installation. The introduction of different materials that can be used to create these durable and long-lasting roofing systems has also become wider in array over the course of time, giving consumers and installers alike more options in terms of roofing system installation. TPO (Thermoplastic Polyolefin) roofing systems, as well as PVC (Polyvinyl Chloride) roofing systems have grown exponentially in their usage over time, despite their differences.
The first and perhaps the most significant difference between TPO and PVC roofing systems is the chemical makeup of each material. PVC roofing membranes are kept flexible through the use of added plasticizers, along with the chlorine taken from salt. TPO roofing systems contain none of these plasticizers, as the chemical makeup of TPO materials does not require them in order to be pliable. This is where TPO roofing gains an advantage, as the plasticizers in PVC tend to break down and migrate over the course of time, being pulled to the surface of the membrane and being washed away by rain and weather elements.
Because of the additives that PVC contains which are needed in order to enable the material to be heat welded and pliable, TPO roofing systems are given another advantage due to the lack of breakdown that occurs in them. Over the course of time, as the chemical makeup and necessary elements of PVC roofs becomes diluted through weathering, they begin to break down and even shrink in some cases, which can create tears in the membrane requiring either patching or complete repair of the roof. TPO roofing systems are made of materials which are designed to withstand the elements, not lending themselves to any of the chemical breakdowns or separations that occur with PVC.
Because of the tendencies of PVC to break down and release its chlorines, among other toxins, TPO seems to be the more ecological choice. Both have reflective qualities that have earned each material energy star ratings and both require the washing of the membrane in order to maintain the reflectivity of the roofing system. One area where PVC roofing systems gain an advantage over TPO membrane systems is that PVC roofing materials have proven themselves to be efficient and cost-effective materials that do last longer than conventional roofing materials, whereas TPO materials haven’t been used long enough to realize the long-term effects and disadvantages.