Why TPO is winning commercial flat-roof replacement
How 60-mil TPO single-ply compares to built-up roofing on cost, service life and reflectivity — and what to specify on your next commercial re-roof.
TPO single-ply has taken a large share of commercial flat-roof replacement. Here is why, how to compare it against built-up roofing on lifecycle rather than sticker price, and what to specify on your next re-roof.
Why TPO, why now
TPO (thermoplastic polyolefin) single-ply membrane has grown quickly as a commercial flat-roof product in California. A white TPO surface reflects a significant share of solar radiation, which reduces heat gain into the building below, and it can be either mechanically fastened or fully adhered depending on the deck and the exposure.
Compare on lifecycle, not sticker price
The mistake to avoid is comparing installed cost per square foot alone. A membrane with a longer service life can cost more on day one and still be cheaper across the life of the building, because the alternative may require an additional tear-off and replacement cycle in the same period. Ask any bidder for installed cost, expected service life and warranty terms together, and run the comparison over the period you intend to hold the building.
The spec
Specify 60-mil rather than 45-mil where budget allows, as the thicker membrane carries better puncture resistance. White reflective surface. Mechanically fastened is typical for re-roof over an existing assembly, fully adhered for new construction. Ask the manufacturer for their warranty terms in writing, and confirm what the warranty actually covers.
When not to use TPO
If the roof sees heavy foot traffic or mechanical equipment, go PVC or modified bitumen. TPO is great for warehouse, retail, office, and low-traffic flat roofs.