Blue roofs: unlocking the potential of the fifth façade

An AT webinar exploring how blue roof systems can transform rooftops into active infrastructure that manages stormwater, supports sustainability targets and unlocks new development opportunities.

As urban sites become denser and climate pressures intensify, managing rainwater effectively is becoming a critical design challenge. Conventional roof systems shed water rapidly into drainage networks that are often already under strain, contributing to downstream flooding and increasing pressure on urban infrastructure.

Blue roof systems offer an alternative approach. Rather than discharging rainwater immediately, they temporarily store and control the release of water at roof level, attenuating peak flows and helping developments respond more effectively to heavy rainfall events. For architects, engineers, developers and clients, this strategy transforms the roof from a passive surface into an active component of a building’s environmental performance.

Key benefits explored in this AT webinar include:

Space optimisation

By providing stormwater attenuation at roof level, blue roofs can reduce or eliminate the need for large underground tanks or surface attenuation ponds. This can free up valuable site area for additional building footprint, landscaping or parking – particularly important on constrained urban plots.

Planning and SuDS compliance

Blue roofs can play an important role in helping developments meet Sustainable Urban Drainage Systems (SuDS) requirements, which are increasingly embedded within UK planning policy. Integrating attenuation into the roof structure can provide a practical and space-efficient way to address these requirements.

Enhanced asset value

Integrating visible sustainability measures can help developments stand out in a competitive market. Roofs that deliver environmental performance while supporting amenity or energy generation can strengthen a building’s long-term appeal for tenants, occupiers and investors.

Multifunctional roofscapes

Blue roofs can be combined with other systems to deliver multiple environmental benefits from the same surface, including:
– Blue-green roofs, where stored water supports passive irrigation of planting.
– Biosolar roofs, integrating water attenuation with photovoltaic arrays to manage heat gain while generating renewable energy.
– Amenity terraces, where roof areas are finished with paving or decking to create communal outdoor spaces.

Through project examples and technical insight, this webinar explores how blue roof systems are being integrated into contemporary developments, and how design teams can use them to deliver more resilient, efficient and multifunctional buildings in increasingly complex urban environments.