TPO Roofing: Costs, Installation & Maintenance Guide
TPO (thermoplastic polyolefin) is one of the most popular commercial roofing materials. Here's a complete guide for building owners evaluating TPO.
What Is TPO?
TPO is a single-ply membrane manufactured from thermoplastic polyolefin compounds. It comes in rolls that are heat-welded together during installation. Available in white, gray, and tan colors, with white being most common for energy efficiency (solar reflectance 0.70–0.80).
TPO Installation Cost
New TPO installation: $5–$9/sq ft including materials, labor, and warranty. Over existing roofing (without tear-off): $5–$8/sq ft. Full replacement with tear-off: $7–$12/sq ft. 10–20-year manufacturer warranties available.
TPO Installation Process
Substrate preparation → insulation installation (if needed) → coverboard → TPO membrane unrolled and positioned → seams heat-welded with hot-air gun → edge terminations installed → penetration boots installed and welded → quality inspection.
TPO Maintenance
Semi-annual inspections checking seam adhesion, flashing conditions, and mechanical damage. Seam re-welding as needed. Drain cleaning. Prompt repair of any punctures. Seam inspection is the most critical maintenance task — TPO's primary failure mode is seam separation.
TPO Limitations
Seams fail over time and require ongoing maintenance. No insulation value added (R-0 for the membrane). At end of warranty, full replacement is typically required. No renewable warranty option. For long-term building ownership, lifecycle cost comparison with spray foam restoration systems is strongly recommended.
What to do with a TPO roof that's leaking?
If your TPO roof is leaking, you have a few options:
- Complete tear-off and replacement (most expensive)
- Install spray polyurethane foam over it (next expensive)
- Install a spray-on roof coating system over it (least expensive)
The most popular option is the spray-on roof coating system. Here are some common questions regarding roof coating systems and TPO:
How much does a roof coating system cost?
As of June 2026, the ballpark cost is $3.50 to $7 per square foot.
The price greatly fluctuates depending on how much of the existing roof needs to be removed and replaced (you cannot install coating over poor-conditioned membrane, loose seams, or wet insulation), and how long of a warranty you would like (a 20-year warranty gets a 50% thicker application of coating than a 10-year warranty).
How long of a warranty can you get?
Most contractors offer 10-20-year warranties.
- The 10-year warranty gets a 20 mil dry film thickness of coating.
- The 15-year warranty gets a 25 mil dry film thickness of coating.
- The 20-year warranty gets a 30 mil dry film thickness of coating.
The warranty can be handled through the contractor or the coating manufacturer. It's best to get a warranty through the manufacturer because it remains active if the roofing contractor goes out of business.
Are there any problems with roof coating systems?
Yes.
There are 3 types of coatings that are used for commercial roofing projects:
- Acrylic (least expensive, least coverage rate, best for non-flat roofs)
- Silicone (best overall in terms of coverage and performance)
- Urethane (better than silicone, most expensive)
If you live in Ohio and install acrylic on a flat roof, you may be in trouble, as acrylics do not handle the elements as well as silicone.
Another problem is that nothing sticks to silicone besides more silicone. If you install silicone and want to install a new roofing system, you likely need to install a board over the top first.
The last problem with coatings is that they are usually installed in white or light grey. This is to maximize the UV reflectivity. The color will get dingy with weather, dirt, debris, etc. This won't hurt performance; it's just an aesthetic issue.