Mount Waialeale in Hawaii is the rainiest place on earth. Better there than inside your commercial property. If your low-slope or flat roof is leaking, you might well feel like all the water in the world is getting inside and ruining inventory, damaging equipment, or making customers and employees sick. You ask, “Why is my flat roof leaking?” One word: ponding.
What is Flat Roof Ponding?
When water does not drain away or evaporate from your flat roof within 48 hours of a downpour, you have a ponding issue. Ponding creates small pools of water that sit on your roof, testing the ability of your top layer of roofing to keep water out of your roof deck and insulation.
Ponding can occur anywhere on your roof but is commonly found around internal drains, scuppers in your perimeter parapets, around HVAC curbs, and in the middle of vast expanses of a flat roof, where the deck itself may sag.
What Causes Ponding?
Ponding is caused by compressed insulation that lowers the built-in slope of your “flat” roof (it’s really a low-slope roof). That low spot collects rainwater, melting snow, or other precipitation. Structurally incorrect slopes can cause ponding, as well.
Ponding can also happen when organic debris builds up and allows seedlings to take root. Soon your roof looks like a weird and wild garden.
Perhaps the most common cause of ponding is a clogged drain. Either your internal drains or your perimeter scuppers can easily be overwhelmed by debris swept into them by moving water. Once clogged, the drain stops being a drain and starts being a dam. Water backs up. The water’s weight compresses insulation and the condition worsens.
How is Ponding Fixed?
Though you would be right to enlist your local, reliable commercial roofer in remedying ponding problems, your own facilities crew can alleviate some issues:
- If safe, have your staff clear internal drains and parapet scuppers of any debris
- If safe, have staff sweep the roof clean of fallen organic matter, including leaves, twigs, branches, and any soil
Your local commercial roofer is your greatest weapon in the ponding predicament. Your roofer can fix the slope, replace compressed insulation, unclog drains and reseal around them, and hunt down other causes of leaks. Trust your roofer, not a general contractor, to cure ponding.
Please contact VanWeelden Company today to discuss your commercial roof ponding. We offer complete and professional solutions.