Commercial roofing basics for small building owners
Last updated
Short answer: Most small commercial buildings have low-slope membrane roofs: TPO, EPDM, modified bitumen, built-up roofing, or spray foam. Typical lifespans run from about 7 to 30 years, depending on the system.[1] Inspect twice a year and after major storms, keep drains clear, and hire using the FTC's license, insurance, and written-contract checklist.[2]
Most commercial buildings have low-slope roofs covered by a membrane system. The main options are TPO, EPDM, modified bitumen, built-up roofing, and spray foam.
How long do commercial roofs last, and what do they cost?
InterNACHI's typical lifespans: TPO 7–20 years, EPDM 15–25, modified bitumen 20, and built-up roofing 30.[1] Angi lists TPO at $4 to $14 per sq ft installed. Large commercial jobs often price differently than residential ones.[3]
What maintenance matters most?
- Inspect twice a year and after major storms.
- Keep drains and scuppers clear. Ponding water shortens membrane life.
- Track penetrations from HVAC and other trades, since they're common leak points.
- Foam roofs need recoating on a schedule.[4]
How should you hire a commercial roofer?
Use the same license, insurance, and written-contract checklist the FTC recommends for any contractor.[2] The estimator on this site is designed for homes. For commercial buildings, request a free inspection and note "commercial" in the details.
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Frequently asked questions
What is the most common commercial roof?
Low-slope membrane systems such as TPO, EPDM, and modified bitumen are the most common.
How long does a commercial roof last?
It depends on the membrane. InterNACHI estimates range from about 7–20 years for TPO to about 30 for built-up roofing.
See 2026 roof replacement cost in your city →
Sources
- InterNACHI, Standard Estimated Life Expectancy Chart. www.nachi.org/life-expectancy.htm
- FTC, How to Avoid Scams After Weather Emergencies and Natural Disasters. consumer.ftc.gov/articles/how-avoid-scams-after-weather-emergencies-and-natural-
- Angi, TPO Roofing Cost. www.angi.com/articles/tpo-roofing-cost.htm
- Capstone Roofing AZ, Foam roof maintenance in Arizona. capstoneroofingaz.com/foam-roof-maintenance-in-arizona/
Sources checked November 4, 2026. Estimates are not quotes. Roofing, insurance, and legal details vary. Confirm with your contractor, insurer, or attorney.