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Exterior and Site

Commercial Roof Repair

Most commercial roofs are low-slope systems, EPDM, TPO, PVC, or built-up asphalt, that fail at seams, penetrations and drains rather than across the field of the membrane. A leak that shows up on a ceiling tile often started feet away, where water tracked along a deck seam before finding a path down. Good repair work traces the leak to its source, matches the fix to the existing membrane type, and documents the repair so it holds up under the next roof inspection.

If it fails: the first hour

What the site contact should do before the technician arrives.

  1. Move product, equipment and files out from under the leak
  2. Place containment buckets or tarps and mark the wet area
  3. Photograph the ceiling damage and the extent of the water before cleanup starts
  4. Shut off power to any fixtures or outlets near the leak if water is dripping on them
  5. Call the roofing contractor and give the exact location within the building

What fails

Seam separationHeat-welded or adhered seams on TPO and PVC membranes open up as the membrane expands and contracts with temperature swings, letting water in at the lap.
Flashing failure at penetrationsPipe boots, HVAC curbs and vent flashings dry out, crack or pull away from the membrane, which is the single most common leak point on a flat roof.
Ponding water degradationAreas with inadequate slope or a low spot near a drain hold water for more than 48 hours, accelerating membrane breakdown and algae growth.
Blocked or damaged roof drainsDebris, granule buildup or a crushed drain bowl backs up water on the roof surface, adding weight and pushing water past flashings.
Blistering and membrane fatigueTrapped moisture or air under the membrane expands with heat, creating blisters that eventually crack and let water through.
Punctures from foot traffic or hailMechanical contractors, satellite installers or storm debris puncture the membrane, creating a point leak that is easy to miss during a walk-through.
Coping and edge metal failureLoose or rusted edge metal and coping caps let wind-driven rain behind the membrane termination at the parapet.
Skylight and curb leaksGasket and sealant failure around skylights or equipment curbs lets water in at a joint that is rarely visible from the interior.

What a service call includes

  • Interior leak tracing to locate the source point on the roof, not just the ceiling stain location
  • Visual and, where needed, moisture-meter inspection of the membrane, seams and flashings in the affected area
  • Cleaning and drying the substrate before any patch or weld is applied
  • Membrane-matched repair, heat weld for TPO/PVC, seam adhesive or liquid flashing for EPDM, hot asphalt or cold patch for built-up roofing
  • Re-securing or replacing failed pipe boots, curb flashing and termination bars
  • Clearing debris from the affected drain and confirming water flows off the roof
  • Photo documentation of the leak source and the completed repair
  • A written report noting any additional deficiencies found, such as ponding or edge metal in poor condition

Preventive checklist

The items a maintenance program should carry for this system. Build a combined checklist across systems with the checklist builder.

Spring

  • Walk the full roof surface and check for winter storm or ice damage
  • Clear debris from drains, scuppers and gutters before spring rain season
  • Inspect flashing and sealant at all penetrations

Fall

  • Remove leaves and debris before they compact into drains over winter
  • Check pitch pans and re-fill with sealant if cracked
  • Inspect edge metal and coping for loose fasteners before winter wind

Quarterly

  • Visual walk of the membrane for blisters, punctures and seam lift
  • Check ponding areas after a rain event within 48 hours

Annual

  • Full roof inspection with a written condition report and photos
  • Core sample or infrared moisture scan on roofs over 10 years old
  • Review warranty status and confirm any repairs were done by an approved contractor

What it costs

itemtypical rangewhat moves it
Emergency leak repair, single point$400 to $1,500Varies with roof access, membrane type and whether interior damage mitigation is needed
Seam or flashing repair$300 to $2,000Length of seam and whether scaffolding or lift access is required
Drain replacement$800 to $3,000Depends on whether the drain bowl and deck penetration need to be reworked
Section membrane replacement$8 to $18 per square footHigher end for PVC and multi-ply systems versus single-ply EPDM
Full roof inspection with report$300 to $900Roof size and whether infrared moisture scanning is included

National ranges. Local labor, access, after-hours timing and materials move them. Multi-site programs usually price below one-off calls.

When this is an emergency

Active water intrusion into occupied space, electrical equipment, or product inventory during a storm.

How to choose a provider

  • Ask whether the technician is certified to work on the specific membrane type installed on the roof, EPDM, TPO and PVC require different training and materials
  • Confirm the contractor will not void an existing manufacturer warranty by performing the repair
  • Ask for photo documentation as standard practice, not an add-on
  • Check whether the provider offers a maintenance program with scheduled inspections, not just reactive repair calls
  • Ask how quickly they can respond to an active leak and whether emergency service is available after hours
  • Confirm they carry liability insurance and workers compensation coverage for roof work

Questions

How long does a typical roof leak repair take?

A single point repair, such as a flashing or seam fix, is usually completed in a few hours once the leak source is located. Locating the source can take longer than the repair itself.

Can a roof be repaired instead of replaced?

In most cases yes, if the membrane is structurally sound and the damage is localized. A roof past 75 percent of its expected service life with widespread issues is a better candidate for replacement.

Does roof repair void the manufacturer warranty?

It can, if the repair is not performed by a contractor certified for that membrane system or if incompatible materials are used. Ask the contractor to confirm warranty compliance before work starts.

What causes most flat roof leaks?

Flashing and penetration points, not the open membrane field. Pipe boots, curbs and drains account for the large majority of leak calls.

How often should a commercial roof be inspected?

At minimum twice a year, spring and fall, with an additional walk after any major storm or hail event.

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