Most PVC roof damage comes down to three things: punctures, failed seams, and shrinkage that pulls the membrane away from edges and penetrations. Small, isolated damage on a membrane still in its service life is usually a heat-welded patch or a seam repair. Widespread shrinkage, systemic seam failure, or a roof past 20 to 25 years usually means replacement pencils out better than chasing leaks. In San Antonio the heat is the real driver. The daily temperature swing cycles the membrane until the weak points let go. A commercial roofer should get on the roof, find every leak point, and tell you straight whether it’s a repair or a tear-off.
A PVC roof is one of the better flat-roof systems you can put on a commercial building. It’s chemical-resistant, it shrugs off grease and ponding better than most, and a clean install lasts a long time. But it’s a membrane, and membranes take damage. The real trick is catching it early, because a small puncture turns into wet insulation and a stained ceiling faster than most owners expect.
Most of what we find falls into three buckets. Punctures, from debris, hail, or someone dragging an HVAC part across the roof. Seam failures, where the heat-welded laps pull apart. And shrinkage, where the membrane tightens over the years and lifts away from the edges and the rooftop penetrations. Each one leaks a little differently. Each one gets fixed a little differently.
And if you manage property in San Antonio, the heat is doing more than you think. It isn’t one bad storm. It’s the daily swing, hot afternoon to cool night, expanding and contracting the membrane thousands of times a year until a weak point finally gives.
What are the most common types of PVC roof damage?
Three failures cover most of what we see on PVC. Punctures are the obvious one. Sharp debris, hail, a dropped tool, or a poorly mounted piece of rooftop equipment, and you’ve got a breach that lets water track under the membrane where you can’t see it.
Seam failures are the one that scares property managers, and they should. PVC seams are heat-welded, not glued, so a good seam is as strong as the field of the membrane. But a cold weld from a rushed install, or years of thermal movement, and the lap starts to open. When a seam goes, you don’t get one neat leak. You get water running along a whole run of roof.
Shrinkage is the slow one. As PVC ages it tightens, pulling back from parapets, drains, and pipe penetrations. That tension opens gaps right where the roof is hardest to keep watertight, and it puts strain on every seam at the same time. Out here, daily swings north of 40 degrees speed all of this up. The membrane never stops moving.
What tools and materials does a PVC repair take?
A real PVC repair isn’t a tube of caulk from the hardware store. The patch has to be the same PVC, matched to the thickness and chemistry of your existing membrane, or it won’t weld and it won’t last. Wrong material is the number one reason a “repair” leaks again six months later.
The work itself runs on a hot-air welder, not adhesive. A good crew welds around 1,000 degrees, watches the temperature with a probe, and rolls every weld with a hand roller to drive out air pockets. Add cleaning solvents to prep the surface, reinforcement fabric for high-stress spots, and the fall-protection gear that any honest crew uses on a roof. For finding the leak in the first place, electronic leak detection and an infrared scan pull double duty, because the wet spot inside the building is rarely right under the hole in the roof.
How do you repair a PVC roof leak, step by step?
It starts with cleaning, not patching. The membrane around the damage gets scrubbed with an approved solvent and dried completely, because any trapped dirt or moisture kills the weld. We prep an area bigger than the damage so the patch has clean PVC to bond to on every side.
Then the patch goes on. Cut with rounded corners, because square corners concentrate stress and start the next tear. The welder brings the patch and the membrane up to temperature together, the crew moves at a steady pace, and the roller seats the whole thing into one continuous piece. Done right, the repair is as strong as the roof around it. Here’s the honest part: a clean-looking patch and a sound weld are two different things, and you can’t tell them apart from the ground. That’s the whole case for getting it done by someone who welds PVC for a living.
When is a PVC roof repair too big to DIY?
Some PVC damage is a legitimate patch. A single puncture on a newer roof with easy access, sure. But a lot of it isn’t, and knowing the line saves you money.
Once the damage runs past roughly 10 square feet, or you’ve got leaks popping up in several spots at once, you’re not looking at a patch anymore. That’s usually a sign the membrane is failing as a system, and patching it is throwing good money after bad. Same story when the water has gotten into the decking or the insulation. By then you’re not fixing a roof, you’re fixing a building, and that needs eyes on the structure underneath. And there’s the warranty. Most membrane manufacturers void coverage the second an unauthorized repair touches the roof, so a DIY patch can cost you far more than it saves.
How do you prevent PVC roof damage?
Most PVC failures we get called for were preventable. The roof gave warning signs for months, nobody was up there to see them. A simple inspection rhythm fixes that. Walk it after big storms, and get a professional on it a couple of times a year.
The cheap stuff matters most. Keep the drains and scuppers clear so water isn’t sitting on the membrane, because ponding is what turns a small problem into a torn seam. Clear debris before it gets walked into a puncture. Check the penetrations and the perimeter, since that’s where shrinkage shows up first. The math is simple: proactive maintenance runs about a dime to fifteen cents a square foot a year, reactive repairs run closer to a quarter and climbing once damage spreads. A real maintenance program also keeps your manufacturer warranty intact, which is worth more than the visit costs.
How do you choose a PVC roofing contractor?
PVC is a specialty, not general roofing. The thing you’re checking for is whether they actually weld membrane, day in and day out, or whether they’re a shingle crew taking a flat-roof job. Ask how they prep a weld, what welder they run, and how they check a finished seam. A crew that does this for a living will have fast, specific answers.
Then the basics. Current license, bonding, insurance for commercial work, and a manufacturer certification that keeps your warranty valid. Ask for recent commercial PVC jobs and actually call a reference. And local matters more than people think, because a contractor who works San Antonio roofs already knows what this heat does to a membrane and specs for it. The crew on your roof should know thermal movement cold, not be learning it on your building.
Get your PVC roof checked by BH Roofing
If your PVC roof is leaking, punctured, or just getting old, the worst move is waiting for it to get worse. BH Roofing handles commercial and residential PVC work across San Antonio, from a single seam repair to a full restoration. Our crew gets on the roof, finds every leak point, and tells you straight whether you’re looking at a repair or a replacement.
Call BH Roofing at (210) 267-9029 to get your PVC roof looked at. If it’s already leaking inside, that’s an emergency, and we respond within 24 hours.
