Flat roofs can quickly turn into 2nd story swimming pools if improperly sloped or installed with low spots in the roofing. However, there are other issues to check for when water is not draining off your flat roof. This article will discuss how a flat roof is designed and its advantages and disadvantages.
A flat roof is more susceptible to ponding water and snow accumulation, so it must be constructed appropriately. A flat roof is not flat; it has to have the proper slope to allow water to drain into the gutter system. Flat roofs are designed with a 2/12 slope or less, meaning the roof raises two inches for every 12 inches of run. This slope will allow water to drain towards the gutters and not accumulation on the roof. Shingles don’t make your roof waterproof, and they should never be installed on a flat roof; shingles are designed to shed water; therefore, they should only be installed on a roof with a 4/12 slope or higher.
When installing a flat roof, roofers should use the appropriate material to maintain the watertight seal. You can choose to install multiple materials on your flat roof, and the best ones are PVC, Rubber(EPMD), and Built-up roofs (BUR). Unlike asphalt shingles, these materials will maintain a watertight seal while it sheds the water to the gutter system.
Advantages of a flat roof are lower construction cost, extra space for a rooftop deck or air conditioner, durability; they are more accessible for repairs, and they have more of an architectural appeal. Disadvantages are the limited lifespan of 10-15 years; draining or the lack of it is the most significant disadvantage. Flat roofs do not drain well, leading to water accumulating in areas and breaking down the material around seams and penetrations.
Having your roof inspected can determine if the material is breaking down or if the gutters or drainage system is clogged. Repairing damaged areas and unclogging the drains or scuppers will help maintain the roof’s life, increasing the lifespan of your roof and saving you money.