Commercial Roofing Archives

TPO vs PVC membranes... This topic 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.

Let’s start with the nitty-gritty of what the membranes are and how they are alike, then we will talk about the differences.

Similarities of TPO vs PVC Membranes

TPO stands for Thermoplastic Polyolefin, and PVC is Polyvinyl Chloride. Both of these membranes are designed for low slopes and flat roofs. And they can both be implemented with both commercial and residential applications.

PVC has been widely used since the 1960s
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.

Installation (Mechanical)

You may be surprised to know that both membranes are installed pretty much the same way. The subtle differences depend only on the manufacturer. You can mechanically fasten (mixture of screwing and heat welding) the membranes over the top of a rigid sub-surface such as ISO board or Densdeck. (For the love of all things holy, NEVER directly screw to wood – speaking from personal, traumatizing experience).

Installation (Adhesive)

You can also fully adhere (glue) over the same surfaces. Fully adhering also allows you to install over structural or lightweight concrete, tectum deck, or any other surface that you cannot mechanically attach to. When you fully adhere the product, you generally get a smoother surface. This looks tighter and a bit crisper than simply screwing it down. So if aesthetics are important to you, then that’s the way to go.

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. This plate 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.

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TPO vs PVC Membrane 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

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.

All this said...

The most important thing to remember about single-ply membranes is that the roofing system you choose best fitted for your needs is only as good as the company you hire to install it. Not all companies are created equally, just like the membrane manufacturers themselves are vastly different.

The contractor you hire should have enough liability insurance to cover two things.

Anything that could possibly go wrong on the job
And the proper workers’ compensation insurance to cover the workers that could get hurt on your property.

Contractors should also be properly licensed to do the job. A good question to ask the company you’re working with is if they will pull a permit with the proper public authorities. If they are not or cannot pull the proper permit, do not hire them. I mean it, you should ask for a copy of the permit pulled.

Here is a helpful article on picking a contractor.

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.