What is the purpose of a Blue Roof?

Whilst most property developers, building services engineers and local authority planners are very familiar with the concept of designing a green roof – not everyone is as well-versed in knowing what a Blue Roof system is.

In short a Blue Roof is a SuDS technique that is specifically designed for the attenuation of stormwater and to provide sustainable drainage at roof level. At a time where climate change is increasing the intensity and frequency of rainfall events, it has never been more important to carefully consider ways to manage the elevated risk of flash flooding and the additional surface water run-off generated from new and retrofit developments, particularly in city centre locations.

In many ways, the concept of the Blue Roof is simply a recognition that it often makes sense to design a roofing system with the attenuation of water in mind, instead of draining rainfall from the roof as quickly as possible into local the drainage network and watercourses.

What does a Blue Roof system design look and work like?

One of the primary components in a Blue Roof system are the restrictor chambers that are installed above rainwater outlet locations to allow for the efficient control of water flow during times of heavy rainfall.

The restrictor chambers, attenuation voids and drainage geocomposite layers (where specified) provide management of storm water outflows at roof level, providing a means by which rainfall can be released more gradually in the period following a storm event to ensure that sewers and storm drains do not reach exceedance levels. In the absence of Blue Roof system design on new and retrofit developments, there is also a strong possibility of discharge consents being exceeded and untreated water ending up in nearby rivers and lakes.

Environmental benefits

Blue Roofs can also be combined with a green roof finish that helps to insulate the building and keep the building cooler during the summer months, with moisture from the planting helping to cool the surrounding air temperature and reduce the building’s air conditioning demand. In short a Blue Roof system brings a vast range of SuDS benefits to the immediate building and the surrounding area of the development.

Blue Roof system design

If you are considering a Blue Roof system design as part of your future development plans, please contact us to arrange a CPD presentation: https://abg-geosynthetics.com/technical/design-solutions-and-cpd/design-solutions-and-cpd/ or submit your project details here: https://abg-geosynthetics.com/design-solutions/blueroof/

ABG have pioneered the design and install of Blue Roofs for over 15 years now and we are the industry leading experts to assist you in realising the most appropriate system for your project.