Flat roofs on Houston homes are more common than people think
Many houses in greater Houston have a flat section somewhere: a den or garage addition, a carport tied into the house, a covered patio, a porch roof under a second-story window, or the whole roof of a newer modern-style house. Few of those roofs are truly flat. Most are low-slope, built to drain slowly toward an edge, a scupper or an interior drain.
Flat roofs fail in their own way. Shingles shed water because each one overlaps the next; a flat roof is one continuous waterproof sheet, and it only works while every seam, edge and penetration stays sealed. A small opening can let water travel a long way under the surface before it shows up as a stain.
Houston Expert Roofers does none of the work. The number is a no-cost referral line, picked up day or night, that puts you through to an independent, locally owned roofing company that repairs flat roofs. That company inspects the roof, quotes and does the repair.
What flat roof problems look like
You can spot most of these from a second-story window, a neighbor's yard or the ground with a phone camera zoomed in. Do not climb up to look. A low roof over a patio feels easy to reach, but wet membrane is slick and an old deck can be soft.
Ponding water
The National Roofing Contractors Association's standard for proper slope is that no water remains on the roof 48 hours after rain in conditions that allow drying. A puddle still there two days later points to a low spot, a sagging deck, a clogged drain or too little slope, and it keeps the surface and seams wet far longer than they were designed for.
Open or lifting seams
Single-ply sheets are joined at overlapping seams: heat-welded on TPO and PVC, glued or taped on EPDM. Modified bitumen sheets overlap at laps that are torched, mopped or self-adhered. A seam that was not fully bonded, or one stressed by heat and movement, opens a little at a time.
Blisters and bubbles
A raised, soft bubble in the roof surface means the membrane has separated from what is under it. Some blisters stay closed for years; others split and let water straight in. Only the roofer, on the roof, should decide whether one needs to be cut out and patched.
Edges, walls and penetrations
Many flat roof leaks start where the sheet stops: at the metal edge, where the roof turns up a wall of the main house, and around pipes, vents and skylights. A leak inside the house near an exterior wall often traces back to the flashing above it.
Clogged drains and scuppers
Live oak leaves, pine needles and windblown trash collect at the low point where water is supposed to leave. Once the outlet is blocked, every rain becomes a pond, and the water level can rise above seams and flashing that were never meant to sit underwater.
Cracked, crazed or bare surface
Sun and heat age a roof surface. Granule-surfaced modified bitumen loses granules and shows the black asphalt underneath; coatings chalk and thin; older built-up roofs crack where the gravel has washed away. These are signs of age rather than a single failure.
Stay off the roof. Wet, storm-damaged roofs are slick and the decking may be weak, so leave the ladder in the garage. Keep well away from downed power lines and report them to CenterPoint Energy or 911. Indoors, move belongings away from the leak, put a bucket or towels under the drip and keep people out of any room where the ceiling sags. Photograph the damage from the ground and inside the house, then call your insurer and a roofer.
How a roofer repairs a flat roof
People search "how do you repair a flat roof" expecting a weekend project. It is not one. This is what a competent roofer does, so you know what the estimate should describe and can tell a careful job from a smear of sealant.
- Find the entry point. The roofer checks seams, edges, flashing, penetrations and drains, and looks at the ceiling or the underside of the deck to match the stain to its source.
- Check what is wet. If water has gotten under the membrane, the roofer should say how far the wet area runs, because wet insulation or soft decking must be cut out, not covered.
- Prepare the area. Loose material is removed and the surface is cleaned and dried so a patch can bond. On TPO and PVC that usually includes cleaning the old sheet so it will accept a weld.
- Patch with compatible material. A TPO roof gets a heat-welded TPO patch, an EPDM roof gets an EPDM patch with the right primer and tape, and modified bitumen gets new plies over the damaged spot. Mixing materials or relying on caulk alone tends to fail.
- Fix the cause. Clearing or resetting a drain, adding a scupper, rebuilding a low spot with tapered insulation, or re-flashing a wall joint, so the same leak does not return with the next rain.
- Photos and paperwork. Before and after photos and an invoice that names the material, the size of the repair and the workmanship warranty.
The materials on Houston flat roofs, in plain terms
The building code treats these as low-slope roof coverings. Under the International Residential Code, modified bitumen and single-ply membranes need a design slope of at least one quarter inch per foot (a 2 percent slope); the code's reroofing section lets an existing roof that already drains properly be re-covered without adding slope, as the International Institute of Building Enclosure Consultants explains in its advisory on drainage provisions. Knowing which material you have helps you compare quotes.
| Material | How to recognize it | What a repair usually involves |
|---|---|---|
| Modified bitumen | Rolled sheets with a granule or smooth surface and overlapping laps; common on garages, porches and additions | Cleaning, then new plies or a cap sheet torched, mopped or self-adhered over the spot |
| TPO | A smooth single-ply sheet with welded seams, usually light colored | A heat-welded TPO patch on cleaned membrane, or new flashing at a penetration |
| PVC | Similar in look to TPO, also heat welded | A heat-welded PVC patch |
| EPDM | A rubber sheet with glued or taped seams, often dark | Primer and seam tape or an EPDM patch |
| Built-up or gravel | Layers of felt and asphalt, often with gravel on top; found on older homes | Removing gravel, cutting out the damaged plies and building the layers back |
| Coating | A painted-on seamless finish over an older roof | Cleaning and recoating, after the roofer confirms the roof underneath is dry |
About TPO roofing details
When people search for TPO roofing details, they usually mean the installation drawings that show how the membrane is finished at drains, curbs, pipes, walls and outside corners. Those spots, not the open field of the roof, are where a TPO roof tends to leak. If you are comparing quotes for a TPO repair or replacement, ask each roofer whose installation details it follows at your drains and wall joints, and whether its plan affects any manufacturer's warranty already on the roof. That answer tells you more than any brand name on the quote.
When to replace a flat roof instead of repairing it
A repair is the right answer for one split seam, one leaking drain or one damaged patch on a roof that is otherwise sound. Replacement starts to make sense when several of these are true at once:
- Leaks return in new places after each repair.
- The insulation or deck is wet or soft over a large share of the roof.
- Seams are opening along their full length, not in one spot.
- Water ponds across much of the roof because the slope is wrong, not because one drain is blocked.
- The surface is cracked, bare or blistered across most of the roof.
A replacement on a home inside the City of Houston needs a residential roofing permit; small repairs up to 100 square feet in total are exempt, according to the Houston Permitting Center. A replacement is also the time to fix drainage for good with tapered insulation or a new scupper, and to consider a light-colored surface: ENERGY STAR cites Lawrence Berkeley National Laboratory findings that a clean white roof can run about 50 degrees Fahrenheit cooler than a gray one on a summer afternoon.
Say it is a flat or low-slope roof, roughly where it is on the house and what you see: a puddle that will not dry, a leak, a bubble or a seam coming apart. The local roofing company you are put through to comes out, sees the roof for itself and writes up its own price.
Questions to ask flat roof repair companies
About the repair
- What type of membrane is on my roof, and will the patch be the same material?
- Where exactly is the water getting in, and can I see photos?
- Is any insulation or decking wet, and how much will you replace?
- What will you do about the ponding so it does not come back?
- Is this a permanent repair or a temporary one, in writing?
About the company
- How many flat roof repairs like this have you done nearby, and where?
- Can you send your certificate of liability insurance?
- Does this job need a permit at my address, and will you pull it?
- What does your workmanship warranty cover, and for how long?
- Will the repair affect any manufacturer's warranty on the roof?
If a storm caused the damage, read the roof insurance claims guide before you sign anything. You file the claim, and Texas law sets limits on what a roofer may do in it.
How a flat roof repair call works
- Call the numberAn automated assistant answers (832) 662-4107 at any hour and asks which service you need, since the line also takes heating, cooling, pressure washing and water damage calls.
- Describe the roofA leak, missing shingles, hail, a limb on the roof or an old roof you want looked at, plus your part of greater Houston and how urgent it is.
- Get put throughYour call is transferred to an independent, locally owned roofing company, which hears a short summary before it picks up.
- Deal with the roofer directlyIt inspects, quotes and does the work, and you pay it (or your insurer does, as you arrange). If it misses the call, it gets your name, number, city and need to call you back.
Texas has no state roofing license. No state agency licenses roofing contractors in Texas, and a 2025 bill to create one (HB 3344) did not reach a vote of the full House before the session ended. So check what you can: a certificate of liability insurance sent to you, a written contract with the full scope, a permit where your city requires one, local addresses you can drive past, and the shingle maker's warranty registration. Some cities also ask roofers to register. The line does not check any of this for you. How to check a roofer before you hire.
About this line: Houston Expert Roofers is a free phone line, not a roofing contractor. It answers your call and connects you with an independent local roofing company, which inspects, quotes and does the work, and which you pay directly. Companies may pay a referral fee. The line never charges you. Read how the line works.
Related services
- Commercial Roofing in Houston
- Roof Leak Repair
- Roof Flashing Repair
- Roof Inspection in Houston
- Storm Damage Roof Repair
- How Long Does a Roof Last in Houston?