Flat residential or commercial roofs don't offer the same natural water runoff capabilities of steeped roofs such as the gable or gambrel. If the flat roof doesn't have enough drainage or a high enough pitch, rain water can form ponds or puddles of water that stay in place for at least a couple of days. This standing water can start to deteriorate your roofing material and can lead to indoor water damage in the future.
If your roof is experiencing frequent ponding, there are a few different ways your roofers can possibly fix the problem.
Open, Unclog, or Add Drain Pipes
Your flat roof should include, at minimum, downspouts connecting to the gutters to help carry water down and away from the building's foundation. If you have an air conditioning unit on your roof, the unit will also have its own drain pipe to remove condensate away from your roof.
If any of these drain pipes become clogged or closed, the backing up water can start to pond on your roofing material. Hire a gutter service to regularly clean both your gutters and downspouts. Ask an HVAC technician to conduct regular maintenance and cleanings of your air conditioning unit to prevent leaks.
If your roof doesn't seem to have enough drains to carry off the amount of accumulating water, ask your gutter or roofing company to install additional pipes.
A cricket is a raised ridge that attaches to a section of your roof that is having issues draining away water. The sloping edge of the cricket helps guide the water down to a portion of the roof that is doing a better job at draining the water.
Crickets are handy around roof protrusions such as a raised skylight, vent pipe, or chimney. The protrusions naturally don't have a lot of runoff capabilities when installed on a flat roof. A cricket or crickets are also handy when you have a flat roof that connects to another section of roofing such as the roof on another wing of the building.
Crickets can look like metal flashing and can be covered with your existing material for better camouflaging.
Redo the Grade
Despite the name, a flat roof isn't completely flat. The roofing material should have a low slope or grade that helps with drainage. The exact slope needed will depend on your area codes, the type of roofing material used, and personal preference.
If your original roof wasn't installed with a high enough slope, or if damage over the years has reduced the slope, you might need to call in a roofer to redo your roofing material. The costs might seem heavy upfront but can save you a lot of money and hassle in the future as the slope should prevent ponding and its accelerated damage to your roof.