Roof Drainage Design

On many occasions drains are too high and water cannot flow off.

Roof drainage design.

Hence this is by far the most common roof drainage situation. Secondary or emergency roof drainage is required wherever the buildup of water is detrimental to the roof structure. As we will see in steps 3 4 the size of the roof drain lines is dependent on the square feet of the roof area being served by each roof drain. Aco offers functional solutions which are specially designed for flat roof areas and which ensure the water is drained effectively.

One gully can drain at least 150 m2. Secondary drainage shall be provided through the use of sidewall scuppers or internal roof drains. For smaller surfaces gravity drainage systems are the ideal solution. Inner drains are resistant to freezing but can require careful maintenance to prevent problems.

Having sufficient drainage on a flat roof is vital. For larger roofs siphonic drainage systems should be installed. The main benefit of inner drains is that the system is hidden from view. Most flat roofs suffer from poor drain locations or drain levels that are high.

When designing a roof it is essential to pay close attention to where the drains are. For most dwellings you ll find that gutters range in size from approximately 100mm diameter to 150mm diameter assuming gutters with a half round section profile and downpipes range from approximately 60mm diameter to 90mm diameter assuming circular downpipes. Inner roof drains are used on flat roofs and include a low section or channel that collects water and feeds it into a concealed drain that leads to an underground drainage system.