Barbour Product Search is part of the Informa Intelligence Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

How is the number of rainwater outlets required to drain the roof calculated?

How is the number of rainwater outlets required to drain the roof calculated?

A blog by IKO Polymeric... The number and location of rainwater drainage outlets for a flat roof system is calculated using BS EN 12056-3.

The calculation takes into account rainfall intensity, the roof form, and the use of the building. Outlets can be external downpipes served by gutters, or internal downpipes. National building regulations also set out requirements for roof drainage, with accompanying guidance.

The position and number of rainwater outlets should discharge water from the roof as quickly and efficiently as possible in order to avoid putting undue stress on the flat roof structure or the flat roof system. Depending on the designed roof falls, ponding water may be avoided by positioning outlets at points of maximum deflection.

Do green and blue roofs affect rainwater outlet positioning?

Where the flow of rainwater on the flat roof is designed to support a planted green roof, or assist the water attenuation of a blue roof, the rate of discharge should be controlled accordingly. However, it does not inherently change the position of outlets. Outlet manufacturers supply data for their products concerning capacity.

IKO Polymeric can provide a roof drainage calculation service for your project, and also offer rainwater outlets as part of our product range.

Add to Project Board

Create a new project board:

View Single Ply Membranes: Spectraplan & Armourplan Product Entry
IKO Polymeric

IKO Polymeric

IKO Group is a global leader in the manufacture and supply of quality roofing products including shingles, commercial roofing and asphaltic and bituminous waterproofing products. They formed the new division IKO Polymeric in 2005 specifically to...
View company profile
T(01257) 488 000
E[email protected]
WVisit IKO Polymeric's website
 Coney Green Road, Clay Cross, Chesterfield, Derbyshire, S45 9HZ

Make an enquiry to IKO Polymeric

You may also be interested in this related Product News: Are single ply flat roofing membranes suitable for use in green roof systems? [BLOG] Read Now