Commercial Roofing
On a medical office roof in Edinburg, TX, a worn path often runs from the hatch to a row of condensers, and somewhere along it a nick in the membrane the size of a fingernail can go unnoticed. That nick can let water into the insulation for months before a stain shows up in a patient room. Punctures are the plainest kind of roof damage to explain and the easiest to underestimate, because the opening is small and the consequences are not. My first question is always who walks the roof and what they carry.
A puncture can be repaired in an hour, but the repair is only as good as the dry-or-wet answer under it.
Most come from traffic and tools. A technician kneels with a screwdriver, a ladder foot slides, a dropped fastener lands under a boot. Others come from the equipment itself: a unit installed with a sharp edge on its curb, a conduit strap that rubs through the sheet, a satellite mount drilled through without flashing. Hail can do the same from above; the 2012 storms in the McAllen-Edinburg metro show it can happen here, though large hail is unusual for the Valley.
I photograph every hole, cut, scuff and gouge, and I separate the ones that reach the reinforcement from the ones that only scratch the surface.
The pattern of damage tells me about the roof's use. Clusters near hatches and ladders point to access traffic, lines along a unit point to service work, and scattered marks across an open field point to something that fell or blew. Knowing which one I am looking at lets me recommend the fix that prevents the next one: walk pads, a guard on a sharp curb or a rule for what gets carried up.
A small opening over a deck flute can send water several bays away. It runs under the membrane, across the top of the insulation or down the deck, and it stays in the insulation where it cannot dry. I compare the interior report with the roof near the nearest traffic path and then check each puncture with a probe. An infrared scan shows the wet area and marks the edge of the dry test area, so the repair addresses what is under the hole and not only the hole.
The time of year changes how a puncture behaves. In the wet months, a hole takes water daily and the insulation never dries. In the dry months, the same hole may stay quiet and give a false sense of safety. Because the Valley prepares for hurricanes from June through October and for flooding all year, I treat every open puncture as an active one until a moisture reading proves otherwise.
It matters a great deal. A thermoplastic sheet is repaired with a heat-welded patch, a rubber sheet with an adhesive patch and primer, a modified bitumen roof with a heat-applied or adhered patch, and a coated roof with a compatible coating and fabric. The thickness and the scrim in the sheet affect how far the damage runs. I identify the system before choosing the patch. An PVC roof, for example, takes a welded PVC patch and does not accept a rubber one.
Round the corners of every patch. A square corner catches and lifts.
Reinforcement is the other variable. A sheet with a polyester scrim holds up differently from one with fiberglass, and a cut that exposes the scrim lets water wick along the fibers into the sheet. For that reason I cut back to clean, undamaged material before patching, which is why a repair that looks large for a small hole is the right one.
A patch should extend well past the damage onto clean, sound sheet, and it needs to be tested after it is made. If the moisture survey shows wet insulation, that material is cut out and replaced before the membrane is closed. If it is dry, a patch alone restores continuity. When several punctures lie along one path, the sheet there is a wear surface, and I recommend a walk pad system so the next technician steps on a protected route and not on the membrane.
I record the size of each patch, the method used and the test result for the file.
The edge of every patch gets a final check. I run a probe around the perimeter, look for fishmouths, where the patch lifts into a gap, and press on the edge. If anything lifts, the patch comes off and goes back on. A lifted edge is the usual cause of a repair that fails in the first rain, and catching it on the day of the repair is cheaper than a second visit.
The site contact, mainly. Roof access, tie-off points and the route across the roof all need to be agreed, and the people below should know when the repair crew will be overhead. Where air intakes sit near the work, we keep adhesives and fumes away from them. For owners with buildings in McAllen or Mission, the same hail event reached the whole metro area, so the photo record is useful for comparing damage across properties. Foot-traffic damage is related to the condition covered by seam failure repair, since a walked-on seam opens sooner.
When punctures multiply across a roof section, the membrane may have lost the toughness to resist the next one. A brittle sheet cracks at a touch, and a patch quilt makes the roof harder to maintain. At that point the options are a restoration with a compatible coating, a recover over dry insulation or a replacement. I compare them by cost, disruption and remaining life, and I show how the restoration option fits a sound but worn roof.
If walkways are needed, walk pads go in as part of the repair and are placed along the routes people actually use. Their position is drawn on the plan with the equipment they serve, so the next contractor on the roof knows where to step. For roofs with sharp-edged equipment, a simple guard or a rounded cap on the curb costs little and prevents repeat damage. The same walk after a gusty night also covers the perimeter, where a wind-damaged edge shows up first.
Yes. Water that enters a small hole spreads through the insulation and deck and shows up far from the opening. The deciding factor is whether the insulation stays wet, so the moisture check matters as much as the patch.
Mark a route with walk pads between the hatch and each unit, require clean boots and cover sharp curbs. Report any damage so it is repaired the same week.
Repair it anyway and check for moisture. The absence of a stain does not mean the insulation is dry, since water can sit in the roof for months before it reaches a ceiling.
A properly made patch on a clean surface can be, but only if the weld or bond is complete. I test the edges and record the result.
As soon as it is safe to walk. Hail marks can hide small breaks, and a walk with a probe and a moisture check finds them before the next rain.