What causes ponding on flat roofs?

Ponding water is defined by the roofing industry as water that remains on the roof for longer the 48 hours after rain. Understanding why your flat roof is holding water is the first step to finding a solution. The most common reason that flat roofs hold or pond water is because of inadequate or obstructed drainage.Click to see full answer. People also ask, is ponding on a flat roof a problem?Ponding occurs when, after a storm or heavy rain, water collects in pools on the roof. Most pools of water will quickly drain off – or even evaporate – but owners should be aware of the signs that ponding has become an issue. The good news is, ponding will not cause rapid damage or even void a warranty.Beside above, should flat roofs have puddles? Puddles or ponding water is water from rainstorms and snow melts that collects on a flat roof and doesn’t drain or evaporate after 48 hours. A roof should not have puddles because roofs are not designed to hold the weight of a large amount of water. Similarly, how much ponding is acceptable on a flat roof? It is generally considered good practice for flat roofs to be designed to clear surface water as rapidly as possible. According to BS6229 & BS8217, flat roofs should be designed with minimum falls of 1:40 to ensure a finished fall of 1:80 can be achieved, allowing for any inaccuracies in the construction.Do flat roofs always leak?The main reason that flat roofs are more likely to leak is that they are less able to shed water. In other words, they do not allow elements like water to slide off them as easily as steeply sloped roofs do. All roofs are sloped at least a few degrees to avoid the allowance of sitting puddles of water.