Flat Roof Maintenance: What Commercial Property Owners Need to Know

Flat and low-slope roofs are common on commercial buildings, additions, porches, and garages across Southern Wisconsin. They can last 20 to 30 years, but only if they're maintained. Unlike a steep roof, a flat roof doesn't shed problems on its own.

Inspect twice a year, in spring and fall, plus after any major storm. Spring inspections catch winter damage from ice and snow load. Fall inspections make sure the roof is ready for winter.

Keep drains and scuppers clear. Standing water is the number one enemy of a flat roof. Leaves and debris clog drains quickly, and ponding water adds weight, speeds up membrane breakdown, and finds every small opening.

Watch the seams. On EPDM and TPO roofs, seams and laps are the most common failure points. Look for lifting edges, gaps, or separations, especially at corners.

Check flashing and penetrations. HVAC units, vents, pipes, and parapet walls all need tight flashing. Rooftop equipment service crews often damage membranes without realizing it.

Look for blisters, cracks, and punctures. Small issues are inexpensive to patch. Left alone, they let water spread beneath the membrane and soak insulation, which turns a repair into a replacement.

Manage snow load. Heavy, wet Wisconsin snow can stress a flat roof. Know your roof's limits and have a plan for safe snow removal that doesn't damage the membrane.

Consider a coating. A restoration coating can extend the life of a membrane that's aged but still sound, often at a fraction of replacement cost.

Keep records of every inspection and repair. It helps with warranty claims and budgeting for eventual replacement.