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Stormwater management – why a Blue Roof might be the answer

Posted by Maisie Kelly —

2022 was a year of record-breaking temperatures in the UK, with some areas experiencing worrying highs of more than 40°C. The Met Office annual global temperature forecast for 2023 has already suggested that this year will follow suit and may be one of the hottest years on record.

Warmer air holds more moisture, so as our climate continues to warm, scientists anticipate that heavy rainfall events will become increasingly common, almost everywhere. This increases the risk of flooding, meaning rainwater management within urban areas is more critical than ever.

This concern has led to much tighter regulations regarding the management of stormwater. Increasingly, authority is moving from carrots to sticks, making it clear you won’t be permitted to erect your building unless you meet stringent requirements.

One of the fastest-growing ways of meeting your stormwater drainage obligations is to install a Blue Roof. Read on to learn more about stormwater management, Blue Roofs generally and Axter’s own Blue Roof offering, Aquamodul®, and how we ensure best practice with our Aquamodul® Blue Roof Upskilling Course.

Stormwater management through SuDS

With extreme rainfall events predicted to rise, management of subsequent stormwater is increasingly important. This is particularly crucial in urban areas, where natural drainage is limited because more of the surrounding ground surfaces are taken up by buildings and paving. Unless controlled, this stormwater can overwhelm drainage and sewer systems and cause downstream flooding and potential deterioration in river water quality.

Sustainable drainage systems (SuDS) are solutions designed to alleviate these issues by holding or re-using stormwater at source, or decreasing its flow rate into the drainage system. One such solution is a Blue Roof.

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What is a Blue Roof?

A Blue Roof is designed to temporarily hold rainfall after a downpour so the water drains away more slowly rather than cascading rapidly. It is not long-term water storage, only immediate, controlled release of the high water volumes that accompany storm events. It is a recognised SuDS solution, something that will become mandatory soon, so it is one way to meet your regulatory obligations for stormwater management. Unlike other options, such as attenuation tanks, it doesn’t take up ground space, and can be much cheaper than approaches involving excavation.

It is not a waterproofing system and will be installed in addition to a standard roofing solution such as a warm or inverted roof.

In the past, traditional roof designs ensured that water is moved quickly away from the building, so the concept of storing a body of water on the roof, however briefly, can feel alien to some designers and installers. However, with careful design, installation and maintenance the Blue Roof concept solves many stormwater management problems and brings a number of benefits including cost effective installation and potential energy savings.

What is the Aquamodul® Blue Roof System?

Aquamodul® is Axter’s Blue Roof offering, suitable for flat or podium roofs. Excess rainwater collects within voids, spaces created for that purpose, and is slowly released into the drainage system, discharging the water completely from the roof within a 24-hour period.

The system varies in configuration depending on the overall roofing design. With a ballasted roof, for example, the ballast can be used as a layer of voids. Other roof types may require two layers of drainage geocomposites to be laid down. From there, water will make its way down to valved outlet restrictor chambers and discharge slowly.

Aquamodul® is compatible with many finishes, such as a Green Roof. For a trafficked podium deck, heavy-duty attenuation crates can take the weight of cars and emergency vehicles.

At Axter, we guarantee our systems for up to 35 years, which is one of the main reasons why we are so rigorous in the training of our network of Accredited Installers. We pride ourselves on our unwavering commitment to quality and work hard to ensure that every Axter offering is designed and installed with consistent attention to detail.

To find out more about our Aquamodul® blue roof system, contact us.

Or to learn about our Aquamodul® blue roof upskilling course, click here.

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