This question has property owners and roofing companies alike, baffled beyond belief. Let’s untangle the web of confusion that has the roofing industry in an uproar.
Similarities of TPO and PVC
TPO stands for Thermoplastic Polyolefin, and PVC is Polyvinyl Chloride. Both of these membranes are designed for low slope and flat roofs and can be implemented with both commercial and residential applications.
- PVC has been widely used since the 1960’s
- TPO made its debut in the early 1990s, boasting of being the new and improved single-ply roofing membrane.
The membranes are both very flexible, white (other colors are available but why would you want to miss out on the reflective index of white?), and are powerhouses of energy efficiency. They actually reflect up to 91% of the sun’s rays, and as you already know, when you reduce the temperature of the roof surface, you reduce the need for HVAC systems to run as much or as hard. CHA-CHING!!! CHA-CHING!!! Money in your pockets for sure! You’re saving not only due to a reduction in energy bills but also on the maintenance of the HVAC system itself. So you are definitely on the right track no matter what membrane you choose.
That being said, a fully adhered system is always going to be more expensive than mechanically attaching because the adhesives used are pretty pricey. You can also mechanically attach either membrane utilizing a special induction plate that can be welded to the bottom of the membrane with special induction welding equipment. This is a great way to install when doing a membrane system as part of a metal roof retrofit. It is also ideal in areas that are susceptible to high winds.
TPO and PVC Differences
Let’s discuss TPO first.
- The most important thing to note is that not all TPOs are created equally. Quality costs! A good quality TPO will last years if installed properly. Taking cost into account, TPO is the less expensive of the two membranes.
- TPO has a slight advantage when it comes to tear and break resistance and is sufficiently flexible.
- The fire resistance is also surely sufficient.
- High-quality TPO seems to weather well over time with the right team installing it, especially in areas that see colder temperatures.
- TPO does not, I repeat does not like grease, acids or animal fats. Grease traps and cooking exhausts will ruin a TPO roof faster than a politician can break a promise.
- It also does not age well in extremely hot environments, so with our intense Summer climate in South Louisiana TPO may not be for you.
- TPO does not stand up to ponding water. If you have an issue with drainage, then TPO is probably not the right option.
- PVC is no different than TPO in the sense that you get what you pay for when discussing material costs. If you buy the cheapest material, you will get what you pay for. The local big box hardware stores are not the right place to buy this material – I can assure you. That being said, PVC is, and should be, the more expensive product.
- One of the very first things you notice if you are examining PVC and TPO at the same time is that the PVC is considerably more flexible when new. This is due to the addition of plasticizers in the chemical make-up of the PVC. The plasticizers could possibly make their way to the surface and flash off in a very low-quality PVC membrane, but you’re not the kind of person who would buy the cheapest products on the market to protect one of your biggest investments, are you? I didn’t think so.
- PVC is the only solution for restaurants because of its ability to stand up against the same grease traps that will so quickly ruin a TPO roof.
- PVC wins the battle of fire resistance as well, making it the clear choice for lower roofs of a building that have balconies above them. You won’t have to worry about burn holes from discarded half-lit cigarettes being tossed off of nearby balconies causing leaks in your roof.
- Extreme high temperatures do not affect this membrane the same way it does a TPO roof, and that makes PVC better suited for the southern states.
Always remember: the first time you have a failure in your roofing system, the front end cheapest price becomes the back end more costly option.
Choose wisely, my friends.