Rooftop unit curbs, equipment supports and pipe supports for McKinney, TX commercial roofs: flashing repair, rebuilds and coordination with mechanical crews.
Tell us about the building and what you are seeing. We reply with the next practical step.
The curb corner fails first. Where a rooftop unit sits on a raised frame, the membrane has to fold, cap and seal around four corners, and that is the weakest point on the roof. In McKinney, TX, July and August afternoons at the Dallas-Fort Worth station average close to 96°F, so the flashing at a curb cooks for months and then meets a spring storm. We start with the unit, the curb and the flashing, in that order. The first check separates a contained repair from a larger scope: is the water entering at the curb, or only appearing there? A commercial roof leak repair near equipment follows the water path back from the interior mark before anyone touches the unit.
Curb flashing fails in a short list of ways. The base flashing lifts at a corner where the membrane was cut and never fully sealed. The counterflashing or cap opens at a joint. Sealant dries and pulls away from the metal. The curb itself settles or rots, tilting the unit and opening gaps. A unit swap leaves a new footprint on an old curb, and the mismatch shows up as a leak the first heavy rain.
We probe each corner by hand and check the vertical face for cracks, shrinkage and tenting. We look at the height of the flashing above the roof surface, because a curb that is too short lets ponded water over the top. Then we look inside the cap for sealant gaps and fasteners that have backed out.
Condensate lines, overflow trays and refrigerant line penetrations around the unit often get blamed on the roof. We rule them out before cutting the membrane.
Not every unit sits on a curb. Some rest on sleepers or pads set on the membrane. Others stand on frames with small footings that pass through the surface. Pipe supports carry gas, refrigerant or conduit across the roof on blocks or rollers.
Each type loads the roof in its own way. A pad that crushes the insulation below leaves a soft spot that collects water. A frame footing needs its own flashing, and a loose footing lets the frame shift and cut the membrane. A roller support that has seized drags across the surface and wears through the sheet. We check each support for movement, rust and fastener condition, and we look at the membrane beneath for abrasion or punctures.
Where a pipe run crosses the roof at ground level, we suggest raised supports or walk pads so technicians do not trap the line against the membrane. A membrane puncture repair at a support is a small job when caught early.
Roof work at a curb touches the mechanical contractor. The unit may need to be shut down, lifted or disconnected so the flashing can be rebuilt. We agree on the order before the roof opens: who lifts, who disconnects, when the unit goes back, and how long the building can run without it. On an occupied shift, a unit shutdown can mean a tenant space without cooling, so the sequence follows the production window.
The lift plan matters. A crane or lift needs a staging area and a clear path, and in a McKinney office or industrial park, the approach may be shared with delivery traffic. The city identifies office and industrial parks throughout McKinney, with US 75 and the SH 121 Sam Rayburn Tollway among the principal routes serving them, but property-level truck access and roof access must still be confirmed for each work site.
Retail properties raise their own questions. Eight retail development areas are on the city's list, Historic Downtown among them, and older storefronts and larger retail properties call for different roof access and phasing. A rooftop unit over a storefront in Historic Downtown McKinney and one on a larger shopping center roof may need different lift and staging plans.
After the unit is set, we check clearances and reflash to the new frame. The record notes the curb height, the flashing method and the date, so a later leak call can be traced to the right detail.
Spring is the Metroplex's peak severe-weather season, per the Weather Service, and hail, destructive wind, flooding and tornadoes show up somewhere in the region nearly every year. No regional event proves damage at a given property. On equipment, though, it gives a clear list of things to check after a storm: dented covers, displaced units, bent supports, cracked sealant and punctures from wind-driven debris.
Summer is the other stress. Heat dries sealant, shrinks mastic and softens some membranes, and the hours of handling time on a hot roof are limited. We schedule rebuilds early in the day when possible and keep a weather hold in the plan for afternoon storm cells.
Rain is the third factor. May normals reach 4.78 inches inside a 37.01-inch annual total, so water will test any open flashing. We close each curb to a watertight state before the crew leaves, even if the permanent detail comes later.
Small gaps can be repaired: reseal a cap joint, replace a split boot, patch a lifted corner with compatible material. The test is whether the substrate is sound and the membrane around it is dry. If either fails, we cut back to a sound edge and rebuild the flashing.
A full rebuild strips the old flashing, repairs the curb, sets new base flashing with reinforced corners and installs a new counterflashing or cap. For TPO roofing, corners can be heat-welded with prefabricated pieces. On other systems, the method follows the membrane. A flashing rebuilt with the wrong material fails at the first thermal cycle, so compatibility comes first.
When a curb is undersized or damaged, replacing it is often cheaper than patching repeatedly. A new curb can also be built higher, which raises the flashing above ponding.
The record lists every curb and support touched, with before and after photographs, the flashing method, the materials used and the date. It flags items to watch and sets an inspection point after the first storm season. Owners with several rooftops can compare curbs across buildings and plan rebuilds in order of condition.
If solar arrays, new units or antennas are planned, the same record shows where the roof can accept them and which openings already exist. Check the solar-ready roofing options before new supports go up.
Permits may apply when a rebuild changes the roof assembly. McKinney lists the 2024 International Building Code with local amendments among its adopted codes, so owners should confirm the current requirements for the scope. Send the roof plan, the equipment list, the leak location and the operating hours, and the repair gets sequenced to fit the shift schedule.
Send the leak location, the equipment list, the operating hours and the access limits. We will inspect each curb and support and sequence the repair around the building's workday.
Short answers to what owners and facility managers ask before a roof visit.
Patches usually cover failed material instead of replacing it. We cut back to a sound edge, rebuild the corner and record the detail.
Sometimes, for small repairs on a cap or sealant joint. A full rebuild needs the unit lifted or shut down, and we agree on that with the mechanical contractor.
High enough to keep ponded water and splash from reaching the top edge. The height depends on the membrane manufacturer's detail and the roof's drainage, and we check it on the walk.
It dents covers, bends fins and can crack sealant and punctures soft flashing. We inspect the unit, the curb and the membrane around it after a storm.
Yes, wherever a footing passes through the membrane. Sleepers and pads need a protective layer under them instead.
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