A roof inlet for the flat roof ensures proper drainage


According to the regulations, the rainwater accumulated on roofs must be professionally collected and fed to the drainage system, this also applies to a flat roof. There must be at least one drain and sometimes an emergency drain, which must be sized according to the roof area.

Roof inlet for internal drainage

The drainage of many flat roofs is done with internal drainage systems. In this case, a pipe system from the roof drain into the interior of the building, a roof inlet is essential.

The calculation of the number of required roof and emergency drains is based on the precipitation area and the drainage capacity of the planned drainage inlets.

A flat roof inlet, also called Gully, is offered in various designs, aluminum is a popular material. Some of the gullies have a height adjustment, a thermal insulation or a strainer.

With built-in heater

In cold regions manufacturers recommend the use of a flat roof drain with heating. Heated overflows are supplied with a cable for connection to a power outlet, the heating power is usually about ten watts. This prevents freezing of the water.

Properties of a good flat roof inlet

  • space-saving dimensions
  • good roof integration
  • Combination with hot bitumen possible
  • flexible use also for ventilation and ceiling penetration
  • with heat tracing
  • with connection flange

The prices of the manufacturers vary depending on the type of flat roof inlets

A cheap roof drain made of aluminum costs about 35, - Euro, a thermally insulated inlet with foamed-in heating element is 67, - Euro, in an angled version you have to pay 87, - Euro.

  • dachdeckermarkt24.de offers thermally insulated and uninsulated flat roof inlets.
  • loro.de offers various roof inlets.
  • sita.de is a provider of various gullies for flat roofs with a lot of information on the website.

Tips & Tricks

If a massive rain retention on the roof provided, the installation of an emergency overflow can be omitted. This is e.g. in the case of green roofs with peat irrigation the case.


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