Understanding TPO & PVC roofing materials

The thermoplastic single-ply roofing has been on the rise over the last decade. This has been attributed to their lightweight, which is in tune with generally adopted standards of “green buildings”. Today, the two popular single-ply roofing systems in the market are PVC and TPO. Among the two, PVC has been in used for a longer time - from 1960s - in both commercial and residential roofing. TPO is touted as an improved and affordable version of PVC and thereby gaining popularity, but PVC has a proven track record. Both of these roofing systems are more affordable than other conventional built-up roofing systems since they are single-ply. They are often referred as “cool roofs” because of their relativity and emissivity. Reflectivity is the energy being reflected back by the roofing membrane while emissivity is a measure of how a membrane repels or absorbs heat.

If you have been in the roofing market, then you might have realized that there are many choices. You might be aware of PVC and TPO as viable options, but you might not know exactly which one will serve you well. While you can leave all these decisions to your roofing contractors, it will be more sensible if you are armed with adequate information on these roofing systems. Before you embark into any roofing venture, it is important to understand have broken down the similarities and differences between TPO & PVC roofing materials.

The two roofing systems are similar in many areas. First, they are both thermoplastic; they have heat weldable seams and highly resistant to fire. Secondly, both are Energy Star Rate for cool reflective properties and thus, energy savers. They are also light in color - white and gray. Their installation can be fully adhered, mechanically attached or ballasted.

TPO is rising in popularity in both residential and commercial buildings because of its affordability when compared to other roofing systems. Some of the best features of TPO are its innovativeness, energy efficiency and cost-effective qualities. They also resist tears, punctures or any impactful force because of its flexibility. TPO is a roll good system since it comes in small rolls. A typical size of an average roll is 8 feet wide by 50 to 100 feet long. This means that more seams - the weakest part of any roofing system - are needed when installing.

Initially, there were no clear ASTM standards guiding TPO manufacturing resulting in different products in the market. This has, however, been resolved. Being fairly new in the market, TPO manufacturers of are still working out on the best versions of the product through various formulations aimed at increasing durability and longevity. Furthermore, they do not have the longevity proof.

PVC is arguably less long-lasting than TPO given that it contains plasticizers thus, break-down over time and migrate to the surface area. However, practically PVC has a proven track record in terms of performance. Some roofs which were installed three decades ago and still intact. Like TPO, PVC is heat welded, but the structural integrity of the membrane might make installation quicker resulting in better result than TPO. Moreover, PVC roofing systems are manufactured according to ASTM standards.

Majority of roofing products come in either reinforced or non-reinforced material, but PVC is always reinforced. This reinforcement is an indication of polyester scrim, fabric mesh or mat inserted into the material, just like iron rods used in concrete walls. While some manufacturers’ reinforcements are stronger than others, there is structural integrity with a PVC membrane. Generally, reinforcement is equated to better quality. This one of the reasons why PVC is comparably expensive than TPO. Generally, getting TPO & PVC materials would help improve your roofing designs.