TPO (thermoplastic polyolefin) is a single-ply roofing membrane, usually white, rolled out in sheets and joined with heat-welded seams. It is common on low-slope commercial roofs.

What is modified bitumen roofing?

Modified bitumen is an asphalt-based roofing system installed in layers. The sheets are applied with heat, cold adhesive or self-adhered backing, and often finished with a granular or reflective surface.

Which roof is better for hail in Texas?

Both can perform well when the right thickness, insulation and cover board are used. Ask your roofer about impact-resistance ratings and how the system is built, not just the membrane name.

Do I need a permit to replace a commercial roof in Dallas?

Roof replacements on commercial buildings generally require a permit. Your roofing contractor should confirm the requirement and pull it before work begins.

TPO vs. Modified Bitumen: Choosing a Commercial Roof in North Texas

October 17, 2026 · Northlane Enterprises

Most commercial buildings in Dallas–Fort Worth have low-slope or "flat" roofs. When it is time to replace one, two of the most common choices are TPO and modified bitumen. Both are proven systems. The right one depends on your building, budget and priorities.

What is TPO?

TPO (thermoplastic polyolefin) is a single-ply membrane, usually white. It comes in wide rolls, and the seams are joined with hot air welding, which fuses the sheets together.

Strengths

White surface reflects sunlight, which helps with cooling in Texas summers
Heat-welded seams
Lightweight
Usually quick to install on large, open roofs

Things to watch

Quality depends heavily on installation, especially at seams and edges
Thickness options vary, so compare the specified thickness between bids

What is modified bitumen?

Modified bitumen is an asphalt-based system built in layers. It can be installed with heat, cold adhesive or self-adhering sheets, and it is usually finished with granules or a reflective coating.

Strengths

Multiple layers add redundancy
Tough surface that handles foot traffic well
Familiar to many roofers and easy to patch

Things to watch

Heavier than single-ply systems
Dark surfaces absorb heat unless a reflective cap sheet or coating is used
Torch-applied installations need strict fire safety on occupied buildings

North Texas weather matters

Roofs in DFW face long hot summers and spring hail. Whatever you choose, ask about:

Insulation and cover board. These layers under the membrane affect both energy use and hail resistance.
Impact ratings for the full roof assembly.
Reflectivity, which affects heat gain and may affect energy code requirements.
Drainage, since standing water shortens roof life.

Questions to ask your roofer

What membrane thickness are you specifying?
What insulation and cover board are included?
How will you handle flashing at walls, curbs and drains?
What warranty is offered, and who issues it?
How will you protect the building and occupants during work?

Budget beyond the membrane

The membrane is only part of the cost. Tear-off, insulation, edge metal, flashing, drains and any repairs to the deck often make up much of the price. Compare bids line by line.

Plan your roof project with Northlane Enterprises

Northlane Enterprises manages commercial roofing projects across Dallas–Fort Worth through licensed, insured roofing partners. Request a quote to have your roof reviewed.