Is Siphonic Roof Drainage Suitable for Blue Roofs?

Rainwater drainage for blue roofs


Q: Is siphonic suitable for Blue Roof drainage?

While Siphonic Drainage works very well with Green Roof systems, in a Blue Roof scenario we do not recommend siphonic drainage. 

Blue roofs are designed to allow controlled attenuation of rainwater on roofs and podium decks. Blue Roofs have a special outlet which restricts the flow of rainwater from the roof which is then supplemented by overflow gravity outlets set within a dam which will only drain when the water level reaches a certain level. This restricted flow of water prevents the siphonic priming action occurring and as such we recommend a gravity drainage system be used with a Blue Roof system.

We have experience designing the rainwater drainage on multiple Blue Roof projects and our team are happy to answer any queries you may have.

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