A positive drainage system is another way to avoid this problem. Positive drainage is when a flat roof is built with graded areas that help lead water away from areas where water commonly pools. Quite often, the positive drainage will allow water to easily flow into areas with large, easily accessible drains.
How do you stop ponding on a flat roof?
Often, something as simple as a clogged drain can cause serious pooling on a flat roof. Unclogging the drain will solve the problem. The next place to look is at gutters or draining channels. Just like a drain, when a gutter or drainage channel is stopped up, water can’t flow and will inevitably collect on your roof.
Is it normal to have standing water on a flat roof?
Standing water on a flat rooftop is a problem since rooftops are designed to quickly drain out any water as soon as possible so it does not leak into cracks and passageways. It’s best to have a pitch of 0.5/12 or 1/12 that can help drain water towards the appropriate gutter systems.
Should my flat roof have puddles?
Whilst brief and occasional ponding is acceptable on a flat roof, regular or long-lasting ponding could be an indication that there is an issue with the roof that needs to be addressed.
How do I redirect water to my roof?
For example, when you want to divert the water from pouring over a doorway, place the bottom edge to the right of the doorway entrance. Slide it under a shingle then continue sliding the entire piece under shingles, on an angle, over the course of its 5-foot length.
How long can water sit on flat roof?
Specifically, water must remain on the roof for 24-48 hours for the National Roofing Contractor’s Association (NRCA) to consider it ponding. If you have this leftover water, you may notice it collects in dips in the roof or around drains.
Is ponding normal on flat roofs?
Standing water on a flat roof for 12-36 hours after a rain storm can be normal, but according to the National Roofing Contractors Association, any water found ponding on flat roofs for longer than 2 full days should be examined by a professional commercial roofing contractor.