Metal roofing
Architectural shingles
Tile roofing
GAF
Flat & low-slopeFree roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
Styles & brands we work with
See the difference
Before
After
Before
After
Before
AfterFlat Roof Patch in San Antonio, TX
A flat roof patch in San Antonio typically costs between $350 and $900 for a standard repair, with most jobs completed in a single visit lasting two to four hours. The final price depends on the membrane type, the size of the damaged area, and whether the underlying decking needs attention. If you’re seeing water stains on your ceiling or noticing standing water on your roof after a rain, call Crestview Roofing Co San Antonio at (361) 209-8857 and we’ll give you a written price before any work starts. For the broader scope of what we handle, see our Roof Repair in San Antonio page.
Flat roof patch work is its own discipline. Most San Antonio homes use sloped shingle roofs, but plenty of houses built from the 1950s through the 1980s in neighborhoods like Jefferson, Monticello Park, and outside Loop 410 have flat or low-slope sections over carports, porches, additions, and sunrooms. Those sections fail differently than shingle roofs. They pond water. They blister under direct Texas sun. They split along seams. And when they leak, the water has nowhere to run except straight down into your ceiling. Dylan Pace started Crestview Roofing in 2000, and in the years since, we’ve patched hundreds of flat roof sections across San Antonio. The work requires a different skillset than shingle repair, and we treat it that way.
When You Need Flat Roof Patch
Not every flat roof problem means you need Roof Repair services involving full replacement. Here are the scenarios we see most often in San Antonio, and what they usually mean:
- Water stains on the ceiling directly below a flat section. This is the most common first sign. By the time you see a stain, water has already worked through the membrane and the decking. A patch stops the active leak, but the damaged membrane area often extends a foot or more beyond the visible stain inside.
- Standing water that hasn’t drained 48 hours after a rain. Flat roofs in San Antonio catch heavy downpours in spring and fall. Ponding water accelerates membrane breakdown. If you have a low spot holding water, the repair usually involves more than a simple patch, but a targeted patch plus improved drainage in that section can buy years of service.
- Blisters or bubbles in the roof surface. San Antonio heat pushes 100 degrees in summer, and a flat roof surface can hit 140 to 160 degrees. Trapped moisture under the membrane expands and lifts it into blisters. Left alone, those blisters crack and become leaks. Patching them early keeps a small problem small.
- Splits or cracks along seams and flashing edges. Flat roof membranes expand and contract with temperature swings. Over years, the seams where two rolls of membrane meet are the first places to fail. The same goes for the flashing around vents, skylights, and the edges where a flat roof meets a sloped one. A seam split is a routine patch for us.
- Loose or lifted flashing at the perimeter. The edge metal that holds the membrane down at the roof’s edge takes the brunt of San Antonio wind. If it lifts, water drives underneath during storms. This is a common repair on carports and porches that face prevailing winds.
- Punctures from foot traffic or debris. HVAC service calls, satellite dish installation, and tree branches all put holes in flat roofs. A puncture is usually a straightforward patch, but it needs to be addressed quickly before water spreads through the membrane layers.
Our Flat Roof Patch Process
Every flat roof patch we do in San Antonio follows the same visible, documented process. You’ll know what’s happening at each step, and you’ll have photo proof at the end.
- Inspection and written estimate. We send a background-checked, uniformed technician to your home. They’ll inspect the flat roof section, identify the source of the problem, and give you a written price before any work begins. That number is the number on the invoice, no exceptions.
- Prep the repair area. We clear debris, locate the damaged membrane section, and cut back any material that can’t be saved. Good preparation is what makes a patch last through a San Antonio summer and the next spring storm season.
- Patch the membrane. We use manufacturer-backed materials from brands like GAF and CertainTeed. The patch material is cut to extend well beyond the damaged section, then bonded or torched down depending on the membrane type. Every seam is sealed and checked.
- Repair or replace flashing. If the leak involves edge metal, a vent, or a skylight curb, we address that in the same visit. A patch that ignores flashing is a patch that leaks again in six months.
- Document with before-and-after photos. You receive photo documentation of the repair area before we start and after we finish. You’ll see exactly what was done. This is part of The Relay Standard, which governs every Crestview Roofing job.
- You’ll get a digital invoice by text. The invoice comes to your phone, itemized, matching the written estimate. No surprises, no “the job grew once we got up there.”
Flat Roof Patch Pricing in San Antonio
Here are the honest ranges we quote in San Antonio. These assume normal access and a single leak source. If the decking underneath is rotted, the price moves up because that wood has to be replaced before a patch can go on. If your roof has multiple problem areas, each additional patch adds incrementally, but the overall cost per square foot goes down.
| Repair Type | Typical Price Range |
|---|---|
| Small puncture or seam split (under 10 sq ft) | $350 – $550 |
| Medium patch with flashing repair (10 – 50 sq ft) | $500 – $900 |
| Large patch or multiple problem areas | $900 – $1,600 |
| Decking replacement beneath membrane (per sheet) | $75 – $150 added per sheet |
What drives the cost? The membrane type matters. Modified bitumen (often called “torch-down”) costs less to patch than TPO or PVC single-ply membranes. The slope matters too: a roof section with zero slope that ponds water will need a more aggressive repair approach than one with adequate drainage. Accessibility matters: a second-story flat section over an addition costs more to reach safely than a carport at ground level. Material brands also factor in. We use manufacturer-backed materials from GAF, CertainTeed, Owens Corning, and Boral, and some homeowners prefer a specific brand match, which we’re happy to accommodate.
Every estimate covers the full repair: materials, labor, flashing work if needed, and cleanup. The 365-Day Done Right Promise is included with every job at no extra cost. If the patch fails within a year, we come back and fix it free, including a free second visit if needed.
FAQs – Flat Roof Patch
How much does a flat roof patch cost in San Antonio?
A flat roof patch in San Antonio typically costs between $350 and $900 for most repairs, with larger or more complex jobs running up to $1,600. The range depends on membrane type, patch size, and whether decking or flashing needs repair. Call Crestview Roofing Co San Antonio at (361) 209-8857 for an exact written estimate on your Roof Repair Near Me in San Antonio, TX, provided free before any work starts.
Is it cheaper to patch or replace a flat roof?
Patching is almost always cheaper than replacement in the short term, usually by a factor of five to ten. If your flat roof section has one or two problem areas and the surrounding membrane is in decent shape, a patch makes sense. If the roof is past 15 years old, has multiple active leaks, or the membrane is brittle and cracking throughout, replacement becomes the smarter financial move. We’ll tell you plainly which side your roof is on, and we handle both: our Roof Repair in San Antonio page covers the full range.
Can you patch a flat roof during rain?
We cannot safely or effectively patch a flat roof while it’s actively raining. The membrane surface must be dry for the patch to bond. But San Antonio storms pass quickly, and we schedule flat roof work in the clear windows between weather systems. If you have an active leak during a storm, call us at (361) 209-8857 and we can often provide Leak Repair with a temporary tarp or interior mitigation guidance until we can get on the roof. A live person answers our phones 24/7.
How long does a flat roof patch last?
A properly installed flat roof patch in San Antonio should last five to ten years, assuming the surrounding roof is in reasonable condition and the decking was sound. That’s why we back every patch with the 365-Day Done Right Promise. If the repair fails within a full year, we come back and correct it at no charge, with a free second visit included. No negotiation, no runaround.
What is your flat roof patch warranty?
Every flat roof patch we do comes with the 365-Day Done Right Promise, written and included with the job. If the patch fails within 365 days, we return and make it right at no charge. The materials we use, including products from GAF and CertainTeed, also carry manufacturer-backed coverage. The warranty specifics are in your written estimate before work begins, so there’s no question about what’s covered and for how long.
Written by Dylan Pace, Owner at Crestview Roofing Co San Antonio, serving San Antonio.