Which is the right choice for my Commercial Flat Roof? TPO or EPDM?

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This is one of the most common questions we get asked.  With NIR’s goal of extending the life of your Commercial Flat roof, this is a question with many factors to consider.  We put together this helpful article to help all of our building owners and managers understand the pros and cons of both to help them decide. Understand the Pros and Cons of Replacing your Commercial Roof with EPDM or TPO on your Commercial Flat Roof before you sign!

Thermoplastic Polyolefin (TPO) is a single-ply roofing membrane.  

It was introduced in the early 1990s and is marketed as a more economical and efficient alternative to PVC.   It has three layers; TPO polymer base, Polyester-reinforced fabric and 

then a Thermoplastic polyolefin compounded top ply.

Reasons to Like TPO:

  • Cost – Similar, cheaper alternative to PVC but has the same benefits such as hot-air welded seams and energy efficiency.
  • Durable – Resists dirt accumulations, tears and punctures. Flexible enough to adjust to settling and some movement.
  • Easy to Install – Larger, wider and lighter sheets.  This makes fewer seams (less labor cost) and is easier on the installer’s bodies.  It can be installed fully adhered, mechanically fastened or ballasted.
  • Energy Efficiency – TPO’s white reflective surface exceeds the EPA’s ENERGY STAR requirements.  The building will keep the interior thermally comfortable on hot summer days while reducing your air conditioning costs.

Reasons to question TPO:

  • Too Young – There is not enough longevity research out there as it has not been out long enough to study for the long term with only being in the market since the 1990s.  There were some very rough starts with TPO and there were many documented cases of seam failures, cracking, and material failures.   Many manufacturers are still changing formulas as they learn the data from current installs.
  • Heat Load – While providing reflectivity, there has been proof that long term exposure to severe temperatures accelerates the weathering of the material.  
  • Repairs Down the Road – Because TPO requires an electrical source to heat weld all the seams.  If an electrical source is not readily available on your rooftop, leaks or repairs down the road may not be as cost-effective.  
  • Longevity – It is uncertain how long TPO lasts at this time as it is a newer product.  Early manufacturers rate anywhere between 15-20 years on average life span.  (Even longer with a NIR Roof Care Plan®!)
  • Solar Panel Unfriendly – TPO reflects light back off the surface and can cause solar panels to fail.

Ethylene Propylene Diene Terpolymer (EPDM) is a single-ply roofing membrane.   

It was introduced in the early 1990s and is marketed as a more economical and efficient alternative to PVC.   It has three layers; TPO polymer base, Polyester-reinforced fabric and then a Thermoplastic polyolefin compounded top ply.

Reasons to Like EPDM:

  • Cost – #1 choice for Ballasted EPDM is one of the most Cost-Conscious Building Specs compared to other options.   
  • GREEN! – EPDM is a 100% recyclable material.  Not only this, but the carbon footprint to manufacture it is also very low as it takes less energy to produce the material.
  • Fire Resistant – EPDM has been shown to actually slow down the progress of fires.
  • Longevity –  EPDM has been around for over 60 years and has stood the test of time over and over again.  EPDM roofs can be expected to last 25-30 years.   (Even longer with a NIR Roof Care Plan®!)
  • Durability – Compared to TPO (a thermoplastic) which will produce lasting circle pits, hail (up to 3″) will bounce off of EPDM with little to no lasting damage.  It is also very wind resistant and isn’t easily damaged by UV rays.
  • Down the Road Repairs – No Electrical source is needed to install or perform repairs.  This will lower any future repair costs.  It is easily repairable with lower costing options.
  • Solar Panel Friendly – As EPDM doesn’t absorb sunlight, it is a solar panel friendly base.  If you are thinking of solar now or in the future, EPDM is a great choice. 

Reasons to question EPDM:

  • Cost – Fully adhered or mechanically fastened EPDM can sometimes be a little more costly than TPO.
  • Shrinkage – At the end of EPDM’s lifecycle, EPDM can shrink up to 4%. 
  • Visual Appearance – Being a black rubber, it can be boring to look at. This can be easily remedied with coatings that can come in any color that will also extend the life of the roof.  

Bottom line:

With several manufacturers of roofing materials and so many options, it can be hard to understand which product to choose. There can be a good case for any product. Keep in mind that manufacturers reward roofing companies with incentives based on how much product they sell. This has always been done in the industry and while not necessarily a bad thing, it can sometimes sway an installer to use products that might not be a great fit for your roof.  It is important for building owners to ensure they understand the correct products for their building and how the building is being used.   If you are still unclear, contact us to help you decide!  At NIR, Your Roof’s Care Is Our Concern®.  

Connect with NIR Today!

Get in touch with us now to discuss your roofing needs. Our flat roofing specialists are ready to answer any questions and recommend a course of care to protect your roof from any problems. We look forward to hearing from you!