Water is one of the worst enemies of your roof. This is why even relatively flat roofs are designed to drain water off the roof. However, even a perfectly designed and constructed roof may start experiencing ponding problems after some time. Here are three reasons this may happen:
Your House's Foundation Is Settling
When a house is built, everything fits perfectly. After some time, however, the foundation may begin to settle (sink) due to different issues such as the weight of the house, waterlogging of the soil under the house, earthquakes, and collapse of underground tunnels. The settlement of the foundation interferes with the perfect fit of the house; the walls start sagging and cracking, and the walls cave in. This interferes with the original drainage design of the roof, which may lead to ponding.
Deformed Roof Insulation
Roof contractors incorporate drainage systems when installing roofing materials. For example, contractors know that even a "flat" roof must have a certain slope to allow for proper drainage of water. This means everything that interferes with the initial design of the roof may interfere with its drainage and cause ponding.
For example, when the roof starts leaking, it allows water to seep into it and soak the insulation material. The insulation material then becomes heavy due to the added weight of the water and collapses/compresses due to this additional weight. Foot traffic can make the compression even more serious. The deformed/depressed parts of the roof then become perfect points for the collection of rainfall or melting snow.
Lastly, you your roof may also develop a water-ponding problem due to debris accumulation. Dirt, bits of paper, and leaves on the roof interfere with proper drainage of water from the roof. The problem will even be worse if the gutters and downspouts are also clogged. To make matters worse, when water stagnates on the roof even once, it can create a depression on the roof that will allow more water to stagnate the next time it rains, and the cycle continues.
Therefore, don't assume that your roof was improperly installed if it has drainage problems. As is clear from the above discussions, several things can cause water to pond on your roof. Do your part (for example by keeping the roof clean) to prevent roof drainage problems and consult a roofing contractor at a company like David Saner Roofing for a diagnosis and fix if a ponding problem does occur.