The short answer
TPO is white and reflective, which cuts cooling load significantly in Texas, and its seams are heat welded. EPDM is black rubber, extremely durable and flexible, with seams that are adhered rather than welded. In this climate TPO is usually the better default, mainly because of the reflectivity.
Side by side
| Factor | TPO | EPDM |
|---|---|---|
| Color | White, reflective | Black, absorbs heat |
| Cooling impact in Texas | Meaningfully lower | Higher |
| Seam method | Heat welded | Adhesive or tape |
| Seam strength | Very strong when welded correctly | Weaker, the common failure point |
| Puncture resistance | Good | Very good |
| Flexibility in cold | Good | Excellent |
| Typical service life | 20 to 30 years | 25 to 30 years |
Choose TPO if
- Cooling cost is a real line item, which it is in San Antonio
- The building has rooftop HVAC you want to run more efficiently
- You want welded seams rather than adhered
- The roof is highly visible from above and appearance matters
Choose EPDM if
- The building is in a colder climate, which does not describe Texas
- Heavy foot traffic or equipment makes puncture resistance the priority
- The roof has many complex penetrations where flexible membrane helps
- You have an existing EPDM system in good condition worth extending
What this looks like in the Hill Country
Reflectivity is the deciding factor in this market. A black EPDM roof in a San Antonio August runs dramatically hotter than a white TPO roof, which shows up directly in cooling load on buildings with rooftop units. For most of the commercial work we do here, TPO is the default recommendation unless there is a specific reason otherwise.
