What Flat Roof Ponding Is And How To Fix It

A flat roof isn’t really flat, and ponding doesn’t really mean a lovely rooftop garden with a koi pond. Flat roofs provide drainage by sloping very slightly; they are low-slope roofs. Ponding is a bit more complicated, and knowing how to fix flat roof ponding is trickier still.   

What is Flat Roofing Ponding?

A functioning low-slope roof should drain water away or allow it to evaporate within 48 hours of any downpour. When the slight slope of your commercial roof fails, puddles of water accumulate and press down on insulation, increasing the puddle size until unwanted ponds form. 

A commercial roof that needs more than 48 hours to clear any water has a problem with ponding

What Causes Ponding?

Ponding is a vicious circle: a small depression allows a little water to sit, and the water weight pushes down, increasing the area. The next rainfall causes more water to sit, and the pond enlarges. But how did that first small depression begin? 

Ponding has many causes:

  • Clogged internal drains or parapet scuppers
  • Roof leaks
  • Vegetation growing on your roof
  • Too much rooftop access — careless workers stomping on your roof, stepping off walkways and depressing the insulation 
  • A weakened roof deck beneath the exterior layer

All of these problems can be solved by enlisting the help of your local, reliable commercial roofer. 

How Can Ponding Be Solved?

Knowing what causes flat roof ponding is a small part of the issue. Knowing how to fix flat roof ponding is the much larger part. When you engage your commercial roofer to partner with you, you get the equipment, trained crews, and years of experience needed to put a stop to ponding problems. 

Your local roofer will:

  • Document the extent of your ponding problem
  • Ensure all drains flow freely, even under the hardest downpours
  • Build up low spots on your roof
  • Measure and recalibrate your roof’s slope to ensure correct drainage across the field

Remedies might be minimal, or they could require that large areas of underlying insulation be replaced with properly shaped rigid insulation boards. From small low-slope roof repair to a full tear-off and new insulation installation, your local commercial roofer is your best ally in flat roof maintenance and ponding prevention.  

With a call to PSI Roofing, or by contacting us online, you can benefit from the years of experience we have in battling ponding and low-slope roofing challenges.