We are going to explore TPO roofing benefits and concerns. If you want more details on what TPO is and installation options, check out our TPO Roofing product page.
TPO Membrane roofing system is growing in popularity. Since the 1990s, the US has been manufacturing it and it has been on the rise ever since. Currently, around 40% of new industrial roofs are TPO.
The popularity of TPO is a recent trend we are seeing in commercial roofing over the past few years. The main reason is the appeal of business owners and companies wanting a bright white roof. There are benefits to this, but a white TPO roof might not be the best option for you.
In this article, we are going to look at a few of the pros and cons of TPO on commercial roofs.
Benefits of TPO
Let’s address the benefits of TPO roofing first.
Costs of TPO
The one thing we are all concerned about when making a large purchase like a brand-new commercial roof is, “How much will this cost me?” This leads to the first benefit of TPO.
On average, TPO is the more affordable roof for commercial buildings that are sloped (we will address slope and TPO later). When you are dealing with a substantial size roof, the smallest price difference in square feet can make a large difference in cost.
Also, compared to PVC, which is another common white roofing membrane, TPO is usually more cost effective.
Membrane roofing is an option for buildings that have a metal roof, as well. The cost of metal is high, especially at the time of this post (April 2021). To remove metal and replace it with new metal may not be the best option, especially economically speaking.
We suggest if the metal roof and structure underneath is sound, you go with a retrofit flute-fill option. The basic way this works is you cut the insulation to fit in-between the metal flutes (aka flute-fill) and then an additional insulation coverboard is attached over that (see image below for a Carlisle system).
This gives a solid surface to apply a membrane on like TPO. Since the metal roof will already have a slope, this is an affordable option that doesn’t require taking the current metal roofing off. Currently, it is roughly $5 sq/ft.
Request a Roof Inspection to see what the cost would be for your roof.
Aesthetics of TPO
TPO vs. PVC: Both require the same amount of maintenance and the install is roughly the same. We recommend using PVC when there is increased use of exhaust ventilation needed in your facility. PVC does better than TPO for those facilities.
Also, for restaurants that might have exposure to animal fats on the roof, we prefer PVC. As mentioned above, PVC is more expensive than TPO, but the benefits may outweigh the cons in the long run.
TPO vs. EPDM (white): To cut to the chase, we don’t really see much of a need for white EPDM. First, it is very expensive. Second, it is hard to find in stock. For very flat roofs, you will need to use EPDM.
But, there is a better option than going with white. The one that offers the most UV protection would be to use a ballast over the top of the EPDM. If you are going to spend the money for a white EPDM, use the extra funds towards adding ballast.
A side note, there are some areas in the US that are requiring new commercial roofs to be white in their building code. So that may play a factor in your choice of material. But here outside of Greenville, SC and Asheville, NC, that is not the case.
However, the aesthetic value of a white roof may not be what you want when you consider the cautions of having a white roof.
Let’s dive into the concerns.
Concerns of TPO
Before diving straight in, here are a few reasons upfront to not install TPO:
Flat: if there is no way to add slope to the roof, you should not put on a TPO (or any white roof for that matter). We will talk about this below regarding the problem of standing water.
Exposure to animal fat or burns: this usually applies to restaurants, but not always. TPO does not hold up well to either. When it comes to a burn test, PVC holds up the best. Check out this video below from Empire Roofing’s YouTube.
It looks like PVC burns the most but it goes out after extinguished. Note that TPO and EPDM continue to burn.
TPO is touted as energy efficient. True, it is a white roof that reflects heat and TPO is UV resistant. But, here is the thing to consider. What season do you spend the most on for energy costs: winter or summer?
If summer, then going with a white roof that reflects heat and keeps your building cool is the better option. For our clients in Spartanburg and Greenville, this is usually the better bet. It will help lower A/C energy cost in the summer.
In areas where energy costs are higher in the winter, a darker roof is better. It will keep the building warmer in the winter. This is recommended for our clients at higher altitudes in Asheville and Western North Carolina.
More information on this can be found in our post, “How Energy Efficient is Your Roof?“. There we dive into the different Climate Zones.
Standing Water and TPO
The greatest concern with TPO (and PVC) is standing water. Standing water is the enemy of TPO. Let me explain.
For a white roof, you absolutely need to be sure that it has some slope to it so that water can reach the drains or gutters. If the roof is entirely flat, you will have to install crickets and tapered insulation to divert water to the drains and gutters.
However, sometimes these drains and gutters get clogged, or even worse, the slope added to the roof does not divert water to them properly. This causes standing water.
Here is what happens. The water puddles up taking with it all the dirt and debris on the roof with it. This dark water will eventually evaporate leaving behind all that dirt and debris.
As this happens over and over again, an even darker spot is created on the roof. The UV rays from the sun will breakdown the membrane in that spot and lead to the membrane failing there.
In the image below, you can see the TPO being eaten away. Eventually all of the dark spots on the roof will break down.
One way to make sure this is mediated it to have your gutters and drains cleaned and dark spots washed at least once a year. A good maintenance plan from a commercial roofing company should be a yearly budgeted item for your facility. WNC Roofing’s commercial roof maintenance plans cover all sized roofs.
So, these are a few things to consider for TPO roofing and the pros and cons of the membrane. Do the benefits outweigh the concerns? That depends on your needs, location, budget, and roofing structure.
Hopefully, this gave you a few things to consider when you speak with a commercial roofer about your needs.