How local government is looking to build more blue roofs

It's not surprising then to see other major cities across the UK following London’s example. Greater Manchester Combined Authority (GMCA) in their urban development policies emphasise sustainable drainage systems (SuDS), which include blue roofs. The Greater Manchester Spatial Framework encourages developers to incorporate these solutions as part of their plans to mitigate surface water flooding and enhance climate resilience.

Leeds has prioritised surface water management in its Core Strategy. The council recommends blue roofs as an effective measure to manage urban runoff to align with its flood risk management strategies. Birmingham’s Green Infrastructure Strategy also highlights blue roofs as a sustainable option for urban drainage. The council actively promotes their adoption in areas prone to surface water flooding.

A blue roof is a specialised roofing system designed to temporarily store rainwater and control its discharge, reducing the burden on urban drainage systems. Unlike traditional roofs, which drain water immediately, blue roofs incorporate water-retention features such as controlled flow outlets which regulate the release of stored rainwater over time. Encapsulated water storage layers hold water temporarily before gradual discharge. Blue roofs are also frequently combined with green roofs or other vegetation to enhance biodiversity and urban greening. These green roofs also store water increasing the amount held on a roof and which will be discharged under control into the urban drainage system.

The London plan and blue roofs

It is one of the reasons why the London Plan 2021 explicitly supports blue roofs as part of its broader sustainable infrastructure strategy. The document claims they deliver better surface water management by managing rainwater at its source. The Plan particularly prioritises blue roofs for their ability to attenuate rainwater for reuse, irrigation or gradual release.

This not only applies to new roofs, but it is also possible to retrofit existing properties with blue roofs that have concrete decks, capable of bearing the additional loads of encapsulated rainwater.

Under the Flood and Water Management Act 2010, Lead Local Flood Authorities (LLFAs) are tasked with identifying areas of flood risk and implementing measures to reduce them. Blue roofs align with these objectives by contributing to strategies aimed at mitigating surface water flooding. In addition, they provide a sustainable solution for reducing runoff and preventing sewer overflow, enhancing water efficiency, improving biodiversity and contributing to urban greening.

At Proteus Waterproofing, we recognise the transformative potential of blue roofs in urban environments. Our waterproofing systems are designed to meet the demanding requirements of blue roof installations, ensuring durability, performance and compliance with regulatory standards.  

We also offer retrofitting options for buildings with concrete decks where the roof is being refurbished. This is because our systems are adaptable to various structures, enabling more property owners to benefit from blue roof technology.

As already mentioned, we already know that blue roofs play a crucial role in reducing surface water runoff, preventing urban flooding and alleviating pressure on drainage infrastructure. By retaining rainwater temporarily, they help achieve greenfield runoff rates, as recommended in the London Plan.

When combined with living roof vegetation, they also create habitats for wildlife and contribute to urban greening. These features improve air quality, reduce the urban heat island effect and enhance the aesthetic appeal of buildings. Blue roofs also enable rainwater harvesting for non-potable uses such as irrigation and cooling. This reduces the demand for mains water and promotes resource efficiency.

Most importantly, incorporating blue roofs helps developers and building owners meet stringent planning requirements and align with sustainable drainage policies outlined by local authorities and national frameworks.

The challenges

However, while blue roofs offer significant benefits, their implementation requires careful planning and consideration. Existing buildings, as already discussed, must be evaluated for their ability to support additional loads from water storage. Blue roofs also require periodic maintenance to ensure their functionality and prevent blockages in outlets and although blue roofs offer long-term savings, their upfront costs may be a deterrent for some building owners.

That said, as cities grapple with the dual challenges of urbanisation and climate change, innovative solutions like blue roofs are becoming indispensable. The London Plan’s preferential treatment for blue roofs sets a precedent for other local authorities, encouraging a shift towards sustainable urban drainage systems.

Proteus Waterproofing is proud to contribute to this movement by delivering comprehensive blue roof solutions that support resilient, sustainable and vibrant urban environments. Whether for new developments or refurbishments, our expertise ensures that every project meets the highest standards of performance and sustainability.

Without doubt, the integration of blue roofs into urban landscapes represents a significant step towards sustainable water management. Policies like the London Plan and similar recommendations from local authorities across the UK highlight the growing importance of blue roofs in mitigating flood risks and enhancing urban resilience – and Proteus Waterproofing is committed to supporting this vision.

Together, we can build a future where cities are better equipped to manage water sustainably while creating greener and more liveable spaces for generations to come.