EPDM vs TPO Roofing
EPDM and TPO are both single-ply membranes allowed on roofs as flat as 1/4:12 (2 percent), and their standards require the same lab UV exposure, 10,080 kJ.[1, 2] The practical differences are the seams (tape for EPDM, heat welding for TPO) and the color: the standard EPDM sheet we checked is black, with a Solar Reflectance Index of 9, while white TPO starts at 101 initial, 92 after 3 years.[3, 4]
EPDM
Pick EPDM if you prefer taped seams over heat welding, or want the thickest sheet in the examples we checked (45, 60 and 90 mil).[3]
At a glance
| Feature | EPDM | TPO | Source |
|---|---|---|---|
| Material standard | ASTM D4637 | ASTM D6878 | [1] |
| Minimum slope in the code | 1/4:12 (2 percent) | 1/4:12 (2 percent) | [1] |
| Seams | Factory-applied seam tape with primer, or hand-applied seam tape (Carlisle Sure-Seal) | Heat-welded (GAF EverGuard TPO) | [3, 4] |
| Lab UV exposure in the standard | 10,080 kJ | 10,080 kJ | [2] |
| Thicknesses (example) | 45, 60 and 90 mil (Carlisle Sure-Seal) | 45, 60 and 80 mil (GAF EverGuard TPO) | [3, 4] |
| Weight, 60-mil sheet (Carlisle) | 0.39 lb/ft² | 0.33 lb/ft² | [3, 5] |
| Solar Reflectance Index | 9 (black Sure-Seal) | 101 initial, 92 after 3 years (white EverGuard TPO) | [3, 4] |
| Longest warranty mentioned | Carlisle uses its 90-mil EPDM for 30-year warranty installations | GAF EverGuard TPO: up to 20 years (45 mil), 25 years (60 mil) and 30 years (80 mil) | [3, 4] |
| Range in one ICC-ES report (Carlisle) | 45 to 90 mil, black or white | 45 to 80 mil | [6] |
Seams: tape vs heat welding
EPDM sheets are joined with seam tape. Carlisle's Sure-Seal uses Factory-applied seam tape with primer, or hand-applied seam tape.[3] TPO sheets are fused with heat; Carlisle says its TPO is heat-welded, usually with an automatic heat welder.[4, 5]
Color and reflectance
The non-reinforced Sure-Seal EPDM we checked is black, with a Solar Reflectance Index of 9.[3] White GAF EverGuard TPO is listed at 101 initial, 92 after 3 years, and a solar reflectance of 0.81 initial, 0.75 after 3 years.[4] White EPDM also exists: Carlisle's ICC-ES report lists EPDM sheets of 45 to 90 mil, black or white.[6]
Standards and lab testing
The residential code points to ASTM D4637 for EPDM and ASTM D6878 for TPO.[1] Both standards require 10,080 kJ of xenon-arc UV exposure in the lab.[2] TPO is the newer material: it reached the U.S. market in the early 1990s, and its first ASTM standard was published in 2003.[2]
Thickness and weight
In Carlisle's data sheets, a 60-mil EPDM sheet weighs 0.39 lb/ft² and a 60-mil TPO sheet 0.33 lb/ft².[3, 5] Carlisle uses its 90-mil EPDM for 30-year warranty installations.[3]
Cost
We did not find a neutral, published installed-cost comparison for EPDM and TPO, so this page does not show one.
Common questions
Which standards do EPDM and TPO follow?
EPDM follows ASTM D4637 and TPO follows ASTM D6878.[1]
How are EPDM and TPO seams different?
EPDM seams are bonded with seam tape; TPO seams are heat-welded.[3, 4]
Is EPDM always black?
No. Carlisle's ICC-ES report lists EPDM in black and white, 45 to 90 mil, black or white.[6]
Which one is newer?
TPO. It reached the U.S. market in the early 1990s.[2]
Sources
- California Building Standards Commission 2025 California Residential Code, Section R905 Requirements for Roof Coverings (effective January 1, 2026). Accessed November 3, 2026.
- International Institute of Building Enclosure Consultants (IIBEC) Technical Advisory No. 12: TPO Single-Ply Roof Systems, Performance and Service Life (2016, revised 2025). Accessed November 3, 2026.
- Carlisle SynTec Systems Sure-Seal EPDM Kleen Non-Reinforced Product Data Sheet (reprint 605436 EPDM-1117) (December 5, 2024). Accessed November 3, 2026.
- GAF EverGuard TPO 45, 60 and 80 mil data sheet (COMEG876) (2026). Accessed November 3, 2026.
- Carlisle SynTec Systems Sure-Weld TPO Reinforced Membrane Product Data Sheet (reprint 600515 TPO-2012) (January 28, 2026). Accessed November 3, 2026.
- ICC Evaluation Service ESR-1463: Carlisle SynTec single-ply roofing systems (reissued October 2025). Accessed November 3, 2026.
We did not install or test these products. Everything on this page comes from the documents listed above. If a source changes, numbers here may be out of date until our next check. Spot an error? Email [email protected].