A flat roof is defined as any roof with a pitch of ten percent or less. If your commercial building has a flat roof, regular maintenance is essential to prevent damage and ensure the roof maintains its value, provides protection, and looks its best.

As a general rule, perform maintenance on your roof twice a year, in the spring and again in the fall. It’s also advisable to inspect the roof for damage in the aftermath of any severe weather, including exceptionally heavy rain or snowfall, high winds, or hail. The following tips will help keep your roof solid and free from serious damage. 

1. Prevent Ponding

Ponding occurs when snow or rain leaves the roof surface saturated, and water pools in low areas of the roof. Left unresolved, ponding can cause leaking and severe structural damage, up to and including complete roof failure.

If ponding occurs on the edges of the roof, installing hoppers can collect excess water. Ponding in the center of the roof can be controlled using an automatic pump. The best solution, however, is to build up low areas so ponding cannot occur.

2. Drains and Scuppers

Drains, gutters, and scuppers should be cleaned at least twice a year. Debris and backups within your drainage system can leave standing water on the roof.

3. Check for Cracks, Ridges, and Blisters

Large cracks and ridges on the roof can occur due to freeze-thaw conditions, surface stress, and poor workmanship. Large cracks tend to run along roof seams or joints and may require professional repair work. Smaller cracks can sometimes be maintained with commercially available patch kits.

Blisters tend to develop when air or moisture becomes trapped in roof layers, separating the layers and damaging the roof membrane. You may need to patch a blister if any of the following apply:

– Blisters have broken open
– Blisters in laps reduce lap coverage
– Blisters show signs of fatigue cracks
– Evidence of membrane deterioration
– Significant loss of surfacing / gravel.

4. Vegetation and Debris Removal

A flat roof is susceptible to debris accumulation. Left undisturbed, organic debris quickly forms a mulch which traps moisture while providing an anchoring spot for vegetation, including bushes and small trees. Remove all debris from the roof during maintenance.

Pay attention to trees surrounding the roof as well. Remove any branches which could fall onto the roof or scratch against the roof surface.

5. Metal Roofs and Heat

A metal roof is most vulnerable to damage where the seams are fastened. Heat causes the roof material to expand and contract, twisting screws at the seams. Check seams for loose, missing, or overtightened screws, and watch for rust spots around screws.

6. Snow Removal

Heavy snowfall can damage even the best maintained flat roof, resulting in leaks, stress to joints and seams, and roof collapse. Snow should be regularly removed from commercial flat roofs, preferably before it reaches more than a foot in depth.

Removing snow and ice from a commercial roof is potentially dangerous. It’s usually safer to retain the services of a professional snow remover than attempting to resolve the problem yourself. Should you choose to remove snow yourself, be sure to use proper fall prevention equipment.


Awesome post! Thanks for sharing the knowledge and keep up the good work.

George | 29.08.23