Roofing resource · 9 min read
Common Flat-Roof Problems on Ohio Commercial Buildings
Where EPDM, TPO, and coated roofs tend to leak, why water travels, and how Ohio building owners can avoid repeat patching.
Updated July 2026
Most low-slope roof leaks don't begin in the middle of an untouched sheet of membrane. They start where materials stop, turn, drain, or meet rooftop equipment. Add Southwest Ohio's temperature swings and service traffic, and those details take a beating.
Start at the seams, edges, and penetrations
EPDM and TPO aren't repaired the same way. EPDM work may use compatible primers, adhesives, tapes, and cover materials. TPO seams are typically heat-welded with compatible membrane. A bucket of generic coating isn't a repair plan for either one.
Curbs, pipes, walls, drains, scuppers, metal edges, and pitch pockets all concentrate movement and water. Loose terminations, failed sealant, open welds, membrane shrinkage, and later equipment penetrations are common places to investigate.
Ponding water is a clue, not a diagnosis
Water that stays after the roof should have had time to dry collects dirt and works on seams, coatings, and small defects. The cause might be a blocked drain, compressed insulation, poor slope, deck deflection, settlement, or a restricted outlet.
Cleaning a drain can fix a blockage. It can't fix a low deck or crushed insulation. Map where the water sits and check drains, scuppers, gutters, and overflow paths before choosing the repair.
The leak in Suite 4 may have entered above Suite 2
Water can move through insulation, under membrane, or along metal deck flutes before dropping inside. A stain doesn't point straight up to the source. Soft areas, repeated leaks, blisters, or widespread staining may call for moisture investigation beyond another surface patch.
Rooftop work is another frequent clue. HVAC service, dropped tools, sharp panels, loose screws, and repeated foot traffic can puncture or wear membrane. Walk pads and controlled access help only when people actually use them.
- Mark indoor leak locations and note the weather
- Keep roof drains and scuppers clear
- Check the roof after new equipment or service work
- Limit access to known walking paths
- Log every repair by date and roof area
Know what a coating can and can't do
A coating can be useful when the existing roof is dry, stable, compatible, properly prepared, and detailed to the manufacturer's requirements. It doesn't remove wet insulation, straighten a sagging deck, or make bad drainage disappear.
Localized repairs may buy useful years on a sound roof. Widespread moisture, recurring failures, exhausted membrane, or extensive incompatible patches may point toward replacement. The right scope should account for tenant access, business operations, rooftop equipment, and future maintenance.