Flat & Low-Slope Specialist
Flat roofs fail differently than sloped roofs — and they require completely different repair techniques. Our licensed membrane specialists repair all flat roof systems for commercial buildings, residential additions, and low-slope roofs across 40+ US cities.
Free Flat Roof Inspection & Estimate
Membrane-specific diagnosis · Written scope · Same-week scheduling
Every flat roof membrane system has a different material composition, failure mode, and repair method. Using the wrong approach on the wrong system causes the repair to fail. Select your membrane below.
TPO Cross-Section
TPO is the most-installed commercial flat roof membrane in the US. Its heat-welded seams form watertight bonds stronger than the membrane itself — when installed correctly. Most TPO failures occur at seams, flashings, or penetrations where the weld is weak or the membrane has pulled under movement.
How we repair it
Best for & common in
Commercial buildings, warehouses, retail, and flat-roof residential additions. Most common in Sun Belt markets where reflectivity reduces cooling loads.
EPDM Cross-Section
EPDM is a synthetic rubber membrane installed in large sheets. Highly resistant to UV, ozone, and temperature extremes, making it the best choice for northern climates. Most failures occur at lap seams (glued rather than welded) and where the membrane has shrunk away from flashings over time.
How we repair it
Best for & common in
Northern markets (Minneapolis, Chicago, New York, Denver) where freeze-thaw flexibility is critical. Common on homes with flat additions and on commercial buildings installed before 2005.
Modified Bitumen Cross-Section
Modified bitumen is asphalt-based, installed in two or three layers using a torch to fuse them together. It looks similar to a flat asphalt shingle and is common on residential homes with flat or nearly flat roof sections. Blisters, splits, and lap failures are the most common repair types.
How we repair it
Best for & common in
Residential homes with flat additions, porches with roofs, and low-slope sections. Very common in the Northeast and Midwest on 1960s–1990s residential construction.
Built-Up Roofing (BUR) Cross-Section
Built-up roofing consists of alternating layers of roofing felt and hot-mopped asphalt, topped with a gravel ballast or cap sheet. One of the oldest and most proven systems. Very common on pre-1990 commercial buildings. Repairable when localized, but widespread alligatoring (surface cracking) usually means approaching end of life.
How we repair it
Best for & common in
Older commercial and institutional buildings (schools, offices, warehouses) built before 1995. Still widely used on new construction due to its proven track record and puncture resistance.
PVC Cross-Section
PVC is similar to TPO in appearance and installation method, but contains plasticizers that can migrate out over time, causing the membrane to become brittle. Highly resistant to chemicals, oils, and grease — making it the standard for restaurant and food service building roofs where HVAC exhausts fat vapour.
How we repair it
Best for & common in
Restaurant buildings, food processing facilities, and commercial kitchens where grease-laden air contacts the roof surface. Also common in chemical manufacturing and industrial environments.
Flat roofs fail in predictable ways — and every failure type has a specific repair approach. Understanding the failure type is the first step to a lasting repair.
Water standing more than 48 hours after rain accelerates membrane degradation. Root cause is usually inadequate slope or blocked drains.
The most common failure mode. Heat-welded or adhesive-bonded seams separate at laps, allowing water entry beneath the membrane surface.
Air or moisture trapped between membrane and substrate expands under heat, creating raised bubbles. Blisters compromise the membrane bond and eventually rupture.
Flashing at parapets, penetrations, and roof-to-wall junctions fails from movement, age, or improper initial installation. Responsible for over 50% of flat roof leaks.
Surface oxidation, chalking, and brittleness from UV exposure over 15+ years. Visible as fine surface cracking (alligatoring) and loss of membrane flexibility.
Punctures from HVAC equipment, foot traffic, hail, or dropped tools. Even small punctures allow progressive water infiltration under the membrane.
Warning Signs to Act On Now
Our free inspection gives you an honest recommendation either way. Here’s the general framework we use to evaluate flat roof repair vs. replacement.
Flat roof repair costs vary by membrane type, damage extent, and roof accessibility. Here are typical ranges — your written estimate after free inspection will be exact.
| Repair Type | Typical Range |
|---|---|
| Small patch (under 10 sq ft) | $400 – $900 |
| Seam re-weld or re-seal | $400 – $1,200 |
| Flashing repair at parapet or penetration | $500 – $1,500 |
| Blister repair (cut and relay) | $600 – $1,800 |
| Drain repair or replacement | $500 – $1,400 |
| Medium section repair (10–100 sq ft) | $1,000 – $3,500 |
| Large section replacement | $3,000 – $8,000 |
| Full membrane replacement (per sq ft) | $4 – $9 / sq ft |
Why use a flat roof specialist
Using TPO tape on an EPDM roof — or applying adhesive patch over a seam that needs re-welding — creates a repair that looks done but fails within a year. We use manufacturer-specified materials for each system, every time.
Most flat roof failures have an underlying cause — inadequate slope, blocked drain, thermal movement at a penetration. We fix the cause, not just seal over the symptom.
Commercial property owners and managers receive itemised invoices, COI (certificate of insurance) documentation for your records, and can be invoiced on Net 30 terms for qualifying accounts.
All flat roof repairs and replacements carry a 5-year workmanship warranty. If our work fails within 5 years, we return and fix it at no charge. Written warranty document issued on completion.
Flat roof repair requirements differ significantly between commercial buildings and residential properties. We’re equipped for both.
"We had a 15,000 sq ft warehouse with recurring TPO seam failures in the same zone. Three previous roofers had patched it — all three came back within a year. RoofRepair.co diagnosed the underlying cause (thermal movement at the parapet expansion joint was pushing the membrane). Full section replacement plus expansion joint detail. Dry for 18 months."
"Our flat-roof rear extension had been leaking for two winters. Classic Chicago freeze-thaw damage to the EPDM membrane at the parapet. The previous roofer had caulked over the shrinkage — which is exactly wrong for EPDM. RoofRepair.co properly re-flashed the parapet with EPDM materials. First winter completely dry."
"Our restaurant had a failing PVC roof around the kitchen HVAC penetrations — grease vapour had degraded the standard sealants used by our previous roofer. RoofRepair.co used PVC-specific materials rated for kitchen exhaust environments. No leaks since, and they completed the job overnight to avoid disrupting service. Professional at every step."
Membrane-specific diagnosis. Correct materials. 5-year warranty. Commercial and residential.