When a flat commercial roof has deep standing water, this is a condition known as "ponding." When your commercial roof develops a ponding problem, knowing what's causing that problem and how to solve it can help you take care of your building and prevent water damage.
What causes ponding water on a flat commercial roof?
Commercial flat roofs rely on a drainage system to evacuate accumulations of rain and snow. When water begins to pond on the roof, this is caused by clogs in the roof drain.
What can you do to unclog a drain on a flat commercial roof?
To unclog the drain on a flat roof, you'll need to start by removing the grate over the drain. In some cases, the clog may be caused by a layer of leaves or debris that has accumulated on the grate over the drain. When this happens, simply removing the leaves from over the grate will allow the water to flow through the drain.
Often, the clog will be located deeper inside the drain pipe. To clear the drain, send an electric snake or a plumber's auger into the pipe. If using a manual plumber's auger, place the tip of the cable into the drain, then turn the crank to send the cable deeper into the pipe. When using an electric snake, simply insert the tip of the snake into the drain and turn the device on. Different electric snakes may have a different set of instructions. Follow the manufacturer's instructions for your product. Whichever device you're using, you'll know that the clog is gone when the water on the roof suddenly begins to drain.
How can you tell if there's water damage on your roof after the water has drained?
Water is extremely heavy and can cause extensive damage if it is allowed to sit on your flat roof for a long enough period of time. The most obvious sign of damage would be a leak in the ceiling of your building. Even if you don't find a ceiling leak, there may still be water damage to the underside of the roof. To check for damage, look for water spots in the wood and insulation directly beneath the roof.
If you do find damage beneath the roof, contact a contractor to repair your commercial roofing. It's important to do this as quickly as possible after unclogging the drain, because water damage can lead to problems like mold and mildew in the wood of your building.