Why commercial roofs leak on the Coastal Bend
Flat and low-slope roofs rarely fail in the middle of a clean sheet of membrane. They fail where the roof is cut, joined or ends:
- Flashings where the roof meets parapet walls, curbs and skylights.
- Penetrations for pipes, vents, conduit and HVAC lines.
- Seams and laps that open up after years of heat and movement.
- Edge metal and copings loosened by wind or rusted by salt air.
- Drains and scuppers clogged with debris, so water stands and finds the weak spot.
- Old patches made with the wrong material that dried out and let go.
In Corpus Christi, Portland, Ingleside and the rest of the Coastal Bend, the climate speeds all of this up. Strong sun and Gulf heat make roofs expand and shrink every day. Salt air off the bay attacks metal. Tropical storms push rain sideways under edges and up through laps that never leak in a normal shower.
Why waiting on a small leak costs more
A drip is the water you can see. Under the membrane, water soaks into insulation, and wet insulation stops insulating, adds weight and holds moisture against the deck. Left alone, a small leak can mean rusted or soft deck, mold above the ceiling, damaged inventory or equipment, and unhappy tenants. Many roof warranties also expect leaks to be reported promptly. A quick repair is almost always the cheaper repair.
What to do the day you find a leak
- Protect people first. Keep water away from electrical panels, lights and equipment, and mark wet floors.
- Move or cover inventory and equipment under the leak.
- Take photos and note where and when it leaks. Does it leak in every rain, or only in wind from one direction?
- Do not send staff onto the roof, and never go up during a storm.
- Skip the bucket of tar. Random patching can hide the real source and may cause problems with your warranty.
- Call a commercial roofer. Our 24/7 line, (361) 320-3131, is answered day or night.
How we track down the source
Water rarely comes in right above where it drips. It can run along the deck, a joist or the top of the insulation before it finds a way down. We start inside, where the water shows, then walk the roof above and upslope of it. We check every flashing, penetration, seam and drain in that area, look for wet or spongy insulation, and when needed open a small test cut to see how far the water has spread. Then we fix the detail that failed, not just the spot that is easiest to reach.
A repair, or a sign of something bigger?
One failed boot or one open seam is a repair. Leaks in several places, large areas of wet insulation, a brittle or shrinking membrane, or a roof that has been patched again and again point to a bigger decision. We will tell you straight which one you have. When a repair is the right answer, we make it and leave the rest of the roof alone. When it is not, we lay out the options, from a coating or roof-over to a full replacement.
The leaks we see most on Corpus Christi buildings
HVAC curbs and units. Rooftop air conditioning runs hard in South Texas, and the curbs, condensate lines and service traffic around units are a top leak source. Techs walk the same path to the unit for years, drop screws, and set panels on the membrane.
Parapet walls and copings. Retail centers and offices along SPID, Staples Street and Saratoga often have parapet walls. When the coping cap on top loosens or its joints open, water runs down inside the wall and shows up far from the roof.
Pitch pans and old patches. Older roofs often have pitch pans around odd-shaped penetrations, filled with sealer that shrinks and cracks in the heat. They are a classic slow leak.
Wind-driven rain at edges. Tropical systems push water sideways. A building that stays dry in a summer thunderstorm can leak in a tropical storm through edge metal, scuppers and wall flashings.
Metal buildings. On warehouses and shops, cracked screw washers and failed laps are behind most leaks. Our metal building roof repair guide covers them.
What a lasting leak repair looks like
A good repair uses material that matches and bonds to your roof: heat-welded patches on TPO and PVC, the right primers and tapes on EPDM, and proper flashing details instead of a smear of caulk. The repaired area should be clean, dry and smooth, with no loose edges for wind to catch. You should get photos of the problem and of the finished repair, so you know exactly what was done and where. If the repair touches a roof under warranty, it should be done in a way that keeps that warranty in good standing, so tell us who made your roof before we start.
Why owners call Nelson Roof Contracting
We have over 50 years of hands-on experience on Coastal Bend roofs, and every job is supervised. We repair single-ply TPO, PVC and EPDM, Duro-Last, metal and coated roofs, and we serve Corpus Christi, Calallen, Robstown, Portland, Ingleside, Aransas Pass, Port Aransas, Rockport, Sinton, Odem, Kingsville and Alice.
Meet the owners
Nelson Roof Contracting is owned by Nelson and Esperanza Alvarado. Nelson brings over 50 years of hands-on roofing experience to Corpus Christi and the Coastal Bend, and every job is supervised. When you call, you are calling a family business that has been on these roofs for decades.
Office (361) 683-1733
24/7 line (361) 320-3131
Updated October 2026 by Nelson Roof Contracting, Corpus Christi, TX.