TPO and PVC single-ply roofing for Central Texas buildings

What is actually in a single-ply roof?

Five layers, and four of them are invisible once the job is finished. The structural deck carries the load. Insulation above it, usually polyiso board, does the thermal work. A cover board protects the insulation from hail and foot traffic and gives the membrane something stable to bond to. The membrane is a single sheet of TPO or PVC — mechanically fastened, induction-welded or fully adhered, depending on the deck, the wind zone and the building's height. Then the details: flashings up every wall and curb, terminations, pipe boots, drains and pitch pockets. Roofs almost never fail in the middle of the field. They fail at the details, which is where the labour and the skill go.

When is TPO the right call?

On most Central Texas low-slope buildings. TPO is a white, reflective sheet that keeps roof surface temperature down through a long Texas summer, and hot air welds it into what is effectively one continuous sheet with no adhesive seams to fail. It carries the lowest installed cost of the three systems in the table below, and a thicker membrane over a proper cover board buys meaningful hail resistance for a modest uplift. It is the default for office, retail, warehouse and light industrial roofs.

When is PVC worth the extra cost?

When the roof meets chemistry. PVC resists grease, animal fats, solvents and many chemical exhausts that will soften and degrade TPO — so restaurants, commercial kitchens, food-processing plants and buildings with laboratory or industrial stacks get PVC, and the price difference is cheap compared with re-roofing early. PVC is also the more forgiving sheet where a roof carries regular foot traffic to equipment, and it can be welded into walkway pads and detail work that would be awkward in TPO. If your building has none of those conditions, PVC is money spent on a property you will not use.

Why do TPO and PVC seams fail?

Almost always because of how they were welded, not what they were made of. A hot-air weld has a narrow window: too cold and the sheets are stuck rather than fused, too hot and the membrane is scorched and brittle, and both look identical from a ladder. A weld made on a dusty or damp sheet, or made at the wrong speed by a hand welder at a corner the robot cannot reach, is the one that opens two winters later. That is why we probe seams with a hooked tool as we go instead of trusting the appearance, and why seam and termination checks are the first thing on a maintenance visit.

What punctures a single-ply membrane?

People and equipment, not weather. Dropped tools, a service technician dragging a condenser across the field, screws left after an HVAC repair, and hail on an unprotected, unsupported membrane are the usual causes. The defence is a cover board under the membrane, walkway pads on the routes technicians actually take rather than the routes a drawing says they take, and a maintenance visit that finds a puncture while it is still a small hole rather than after the insulation under it has taken a season of water.

Why does a membrane lose adhesion?

On a fully adhered roof, an unbonded area is usually a preparation failure: adhesive applied to a dusty, damp or too-cold substrate, or the sheet laid outside the adhesive's flash-off window. On a mechanically fastened roof, the equivalent failure is a fastener backing out through the plate, which shows itself as flutter in high wind. Neither is visible from the ground. Both are visible on a roof walk, and both are cheap to fix before the wind finds them.

What does Texas sun do to a roof membrane?

Ultraviolet exposure and heat age the top surface of any membrane and consume the stabilisers that protect it, which is why a chalky, crazed surface on an older roof is a genuine condition signal rather than a cosmetic one. A reflective sheet runs cooler and ages more slowly, and keeping the roof clean matters, because dirt destroys reflectivity. It is also why we will not guess a service life from a roof's age alone — a clean, well-drained roof and a ponding, filthy one of the same age are not the same roof.

Tear-off or re-cover?

A re-cover leaves the existing system in place and installs new insulation or cover board and a new membrane over it: faster, quieter, cheaper, and no disposal cost. It is only available when the existing system is dry, the deck is sound, and the code limit on roof coverings has not been reached. A tear-off is the honest answer when moisture has got into the insulation, when the deck needs attention, or when the assembly cannot take fasteners. We would rather lose the cheaper sale than sell you a roof over a wet one.

What happens to your operations while we work?

Tear-off is the loud phase and welding is the smelly one, so both are planned around your tenants. Before we mobilize we agree roof access, staging and parking, tenant notification, and which phases run after hours. The roof is left watertight at the end of every working day — never open overnight — and we photograph progress daily.