EPDM vs TPO Roofing: Expert Roofer’s Honest Take
If you’re wondering whether to go with Ethylene Propylene Diene Monomer (EPDM) or Thermoplastic Polyolefin (TPO) for your commercial flat roof, you’re in the right place. Both have been around for a while, and both have their pros and cons. So how do you know which one to choose? Let’s break it down.
Energy Efficiency
One of the biggest factors to consider between EPDM and TPO roofing is energy efficiency.
If you’re in the southern U.S. or any area with a lot of cooling days or days when you need the building to stay cool when its hot outside, the white reflective surface of a TPO roof helps keep heat out of the building, reducing strain on your air conditioning.
But if you’re up north, say upper Minnesota or Canada where you might have more heating days, meaning you’re trying to keep the building warm most of the time, a black EPDM roof might be the better choice. It absorbs the sun’s heat, helping to keep the building warmer in the colder months.
Longevity and Maintenance
Both TPO and EPDM roofing systems can come with warranties up to 30 years. But the long-term maintenance looks a little different for each.
EPDM (Rubber Roofs):
EPDM roofs rely on seam tape to join pieces together and flashing adhesives around roof penetrations like pipes and curbs. Over time—especially if not installed perfectly—these tapes can begin to lift, peel, or bridge at corners. You may start needing maintenance like caulking around year 10. It’s not unusual for these systems to be solid for a decade before any work is needed, but maintenance will come eventually.
Now while the seams and penetrations tend to wear out over time on an EPDM roof, they are super easy to patch and repair with new flashing when needed.
Rubber roofs have been a mainstay for low-slope or flat roof commercial buildings for 50 years or more. They work if they’re maintained. For a 5,000 square foot rubber roof, I’d expect to spend $500-$1000 a year to keep it in good shape. And that is money well spent because you can literally increase the roof’s lifespan by 50% or more if it’s maintained.
TPO (Thermoplastic Polyolefin):
TPO systems are heat-welded using robotic welders. The plastic-based material fuses together at the seams, creating a strong, single-piece membrane. When done properly, these welds won’t peel or break down like tape can. This makes TPO virtually maintenance-free for many years.
Flexibility and Expansion
Because it’s black and rubber-based, EPDM expands and contracts a lot. On older EPDM roofs, you might see bridging, where the membrane pulls away from corners or even pulls on the drip edge over time, causing it to pull away from the edge of the roof. This can cause serious water leak problems if not addressed.
TPO, on the other hand, contains a scrim—a reinforcing layer of thread that adds structure and stability. It holds its shape and doesn’t shift much over time. That means less movement, less stress on edges, and fewer long-term issues.
My Take: Which One Would I Pick?
If I had to choose a roofing system for a commercial flat or low-slope roof, I’d go with TPO.
EPDM is a solid, proven product. It’s been around longer and it works well in the right situations. But TPO has also proven itself over decades. It’s clean, easy to install, holds up well, and requires less maintenance.
Plus, TPO’s reflective surface is a big benefit here in Pennsylvania—where summers get hot, and in turn energy bills
That said, EPDM has its place, especially for small residential projects where flexibility and ease of installation are key.
If you’re doing a small flat roof section on a home, EPDM might be the better fit.
