Flat roof drainage: everything you need to know

When it comes to flat roof waterproofing systems, properly designed drainage can make the difference between successful protection and insufficient protection. 

The flat roof drainage is important to control water accumulation on the roof during the winter season, especially if you live in a region where rainfall is constant. Snow, leaves and other debris can collect in different parts of the roof and clog the spaces through which water should drain.

Having the best flat roof drainage will avoid risks of damage and leaks that may imply the need to carry out material replacements and major modifications. In the long run, this means a larger financial investment. 

Therefore, in this article we tell you everything you need to know to make sure that the flat roof drainage that your building has is of the best quality. 

Keep in mind that having a team of professional and reputable workers is essential. 

Factors to consider in flat roof drainage

A flat roof drainage is a drainage system designed to control water that accumulates on roofs. There are many factors to consider when verifying the proper functioning of the gutters for the drain.

The main thing is to be clear about the established rules regarding the minimum roof pitch in Quebec or in the region where you live. 

Of course, although they are often called “flat roofs”, these types of roofs are not always completely flat. In fact, it is globally accepted that there should be a minimum slope of 15º.

If this is the case for aesthetic or structural reasons, other requirements regarding airtightness must be met to ensure safety in winter.

Whichever method is used, the main thing is to help keep surfaces dry. Some important things are:

  • The size of the drain is a crucial factor, as it has to do with the hydraulic load. The fittings must be large enough to handle the volume of water it will receive. Otherwise, they will not be able to do their job and the roof will become unstable and unsafe.
  • The location of the flat roof drainage is also important. The drain should be strategically located to ensure that water is diverted and to prevent deterioration of the roof. The drain should be located at a low point on the roof to adequately divert water.
  • The material of the drain and in general the material of the tiles is also an important factor to consider. It must be corrosion resistant to ensure long-term performance.
  • The use of an overflow drain is also a good option when dealing with flat roofs. An overflow drain prevents water overflow by automatically redirecting the water to a safe location when the water level reaches a safe level. This helps prevent damage to the roof and waterproofing system.
    This flat roof drainage system consists of a series of gutters and pipes that convey rainwater to a drainage point, where it is discharged to the sewer system or stored in a water collection tank.
    Overflow drains may also include safety devices, such as water level sensors or control valves, to prevent water from overflowing and causing damage.
  • It is important that you check the flat roof drainage system regularly to ensure that it is working properly. This will prevent potential problems. If necessary, you can request certified roof inspection services.

In addition, remember that it is important to perform regular professional maintenance to check for cracks or excess debris that could pose hazards at some point.