Repair open and split roof seams in McKinney, TX: probe the laps, find why they opened, and reweld or re-bond with tested results recorded for the owner.
Tell us about the building and what you are seeing. We reply with the next practical step.
Probe the lap before judging the sheet. A single-ply roof can look intact from the hatch while a seam six feet away has opened a finger's width, and water finds that line first. In McKinney, TX, where July and August highs average near 96 degrees and spring storms arrive fast, seams carry both heat stress and sudden rain. We start by asking whether the opening is one weld or a whole line of them.
The answer decides the order of work. A local defect gets a local repair. A run of open seams along one rail points to a cause, and the cause has to be corrected or the new weld will fail the same way.
Seam inspection is tactile. We run a blunt probe along every lap, press at the edge and listen for a weld that has not fused. A good weld resists the probe. An open one lets the tip slide in. Each failure is marked on a roof diagram with a distance from a fixed point and photographed with a scale.
The pattern matters. One open seam suggests a local defect, such as dirt in the weld. Several on the same line suggest fasteners pulling out, a crew problem, or movement at a change in plane. Open seams in the cool season, when the membrane contracts, tell another story from open seams in July.
Intersections get extra time. Where a seam crosses a flashing, enters a drain sump or meets a wall, three layers overlap, and the weld there is the hardest to make. We check each junction because T-joints are often the spot left uncovered.
Probing alone does not close the question. After the tactile pass, we look at the sheet in raking light for wrinkles that run along a lap, since those often signal a bond that let go under tension. We also pull a few samples of old sealant at terminations to see whether it still adheres. All of it goes on the diagram so the owner sees one picture.
When a seam is open and the interior is wet, the temporary measure comes first. We seal the lap with a cover strip or tape-down patch, route water away from the opening and protect the floor below. The work zone is marked so other trades stay clear.
Moisture can travel. Water that enters at a seam can run along the deck before it drips, so the ceiling stain is not always below the opening. A leak trace connects the interior mark to the seam, and an infrared moisture survey maps wet insulation when the path is unclear.
On an occupied shift, we plan access so the repair does not block loading or production. Roof hatches, ladders and lifts each have limits, and the facility director confirms which route is available. We close each section the same day.
The repair depends on seam condition and membrane age. A clean lap with a small void can be rewelded or re-bonded. A wider failure needs a cover strip, a piece of membrane welded over the seam on both sides. A badly aged sheet may not accept either, and the section is cut out and replaced.
We test a small weld first on older membrane. If the surface has hardened and will not fuse, we use a larger patch with a compatible adhesive, or we move the repair boundary outward until it lands on sheet that does bond. A patch laid on weak material fails at its edge.
Every repair is tested. Welded seams are probed and checked, and for important roofs a vacuum or pressure test is used where practical. A failed test is redone. If open seams are widespread, patching becomes costly and the roof is telling a larger story, so we compare repeated repair with a recover or replacement.
Fasteners deserve a word. In a mechanically fastened system, the seam sits over a row of plates, and a plate that backs out lifts the sheet from underneath. We reset or replace the fastener before welding, because a perfect weld over a loose plate opens again at the first gust.
Welding and bonding depend on surface temperature and moisture. A roof in July sun can be hot enough to make membrane limp and difficult to weld cleanly, so crews start early and rotate. Cool, damp mornings can prevent adhesive cure, so we wait for the surface to dry.
Spring brings the Metroplex's hail and wind season, and a storm line can end a welding day in minutes. A thunderstorm line can end the day, so we size the repair to what can be closed and leave a temporary cover on anything that cannot.
Near US 75 and the SH 121 districts, a weather hold is coordinated with tenants and deliveries. The facility director gets a short status at day's end: what is welded, what is covered and what waits for the next dry window.
Each membrane has its own seam. Thermoplastic sheets such as TPO are heat-welded, and a good weld fuses two layers into one. Rubber sheets use tape or adhesive, and the bond depends on clean, primed surfaces. Modified bitumen laps are heated or adhered and checked for voids. Built-up roofs open at felt laps rather than welds.
The repair method follows the seam. A thermoplastic seam is cleaned and rewelded, with a cover strip when the lap is narrow. A rubber seam is cleaned, primed and re-taped, or a splice cover is added. A bitumen lap is reheated and pressed or patched with compatible sheet. The wrong method on the wrong membrane looks fine and fails in the first season.
Seams open for reasons the repair should address. Heat cycles pull laps apart. Standing water keeps seams under pressure, which is why ponding gets corrected alongside the weld. Foot traffic abrades laps near equipment, and walk pads protect them. Where flashing also shows distress, the flashing is repaired in the same visit.
Hail changes the picture. A seam near a hail strike may have been stressed even when the surface looks sound, so after a spring storm we probe laps in the struck area and note which ones softened. The repair is the same, and the documentation helps if a claim follows.
The owner receives a seam map: each repair located on the diagram, with method, date and test result. The file shows which seams were repaired, which passed inspection and which are being watched. A return visit after the first heavy rain confirms the roof is dry.
Maintenance visits then include a short probe of the most stressed laps. Owners with many roofs can build this into a multi-site roof program. Buildings in Plano or Richardson can follow the same schedule.
Tell us which area leaks, your operating hours and how the roof is reached. We will probe the laps and sequence the repair around the building's workday.
Short answers to what owners and facility managers ask before a roof visit.
Usually you cannot. Interior stains after rain are a hint. On the roof, lifted edges, wrinkles along laps and dirt lines mark suspect seams. A trained crew with a probe is the reliable test.
Often the cause was not removed. Movement, ponding, traffic or a dirty weld reopens a seam. We trace the cause and fix it with the repair.
Sometimes. The surface must be cleaned, and a test weld shows whether it fuses. If not, we use a cover strip with compatible adhesive, or cut out and replace the section.
Yes. We probe and inspect every welded seam, and use vacuum or pressure tests where practical. Results go on the seam map.
When failures are widespread, the membrane no longer fuses, or the insulation is wet. A cost comparison between repeated repair and a new surface shows where replacement makes sense.
Send a question about the building and we will reply. Or call 555-555-5555.
