A blue roof is an engineered SuDS solution which is closest to source and designed to manage rainwater better where it lands. Offering certainty by design to control the discharge rate of the roof as part of the wider drainage and flood risk strategy.
Climate change is creating more extreme weather events with longer and more intense storm events leading to a greater need for SuDS solutions particularly in urban areas.
A blue roof mimics the natural environment to slow the discharge of rainwater protecting the building and the wider drainage system from flash flooding.
A blue roof is a roof designed to absolute zero falls in compliance with BS6229:2025. It comprises of an area to store water during a storm period and a flow control device to slow the discharge of that water. The depth of the area and the size of the orifices in the device are defined by a calculation we run to comply with the planning requirements of the site.
Attenuation at roof level be that a podium or many stories higher can eliminate the risk of below ground drainage systems such as contaminated land or archaeological findings.
As an engineered SuDS solution you gain greater certainty than that of an outright natural SuDS system, such as a green roof or a planter.
Utilising the outlet as the flow control device we utilise a simple number based setting to allow for clearer quality assurance both at installation and for ongoing maintenance.
Well designed SuDS systems can contribute to BNG (Biodiversity Net Gain), UGF (Urban Greening Factor) and BREAAM credits.
The original and industry renowned second generation hot melt system. For use on all inverted roofs, podium decks, living roofs, blue roofs and car park decks.
Hybrid waterproofing system combining benefits of hot melt systems and polymer modified bitumen membrane technology.
Blue roofs can be used in isolation or as part of a wider range of roof finishes offering a number of complimentary benefits.
A flat roof is ideally suited to generate electrical energy via a photovoltaic array. Through the installation of an Axter Solar PV system, the flat roof can easily be converted into an electrical generator producing clean efficient electrical energy to power the building, the local community or feed back into the national grid.
Green roofs are set to play a big part in the future of sustainable architecture.
A blue roof is designed primarily to manage rainwater by temporarily storing it and controlling its discharge. A green roof incorporates vegetation and a growing medium to provide a planted roof finish.
Axter's Aquamodul® Blue Roof system can be combined with living roofs, solar PV and multifunctional amenity finishes. This allows roof space to contribute to drainage management alongside other building and environmental objectives.
A blue roof’s storage capacity depends on its design and the drainage requirements of the project. Axter blue roof systems are designed to manage stormwater, with controlled discharge over a specified period.
The required storage depth and outlet configuration are established through project-specific drainage calculations. Axter provides these calculations as part of its blue roof design service.
Blue roof design requires calculations to establish the necessary storage capacity and control the rate at which rainwater leaves the roof.
Axter's Aquamodul® Blue Roof system is designed around the drainage strategy and planning requirements of the site. Its design service includes site-specific drainage and outflow calculations to determine the required storage depth and flow-control arrangement.
A blue roof requires a suitable waterproofing system beneath its rainwater attenuation components. Axter’s Force Dalle® waterproofing systems can be used in warm or inverted roof constructions, while Wilotekt®-Plus is suitable for inverted or cold, uninsulated podium deck constructions.
The appropriate system depends on the roof build-up and project requirements. Axter can provide coordinated waterproofing and blue roof design as part of its system offering.
Yes. Axter's Aquamodul® Blue Roof system can be combined with living roof finishes, solar PV and multifunctional amenity finishes.
This enables the roof to provide rainwater attenuation alongside other uses. The proposed roof build-up and finishes should be coordinated as part of the project-specific design.
Blue roofs can form part of a sustainable drainage system (SuDS) by controlling the rate at which rainwater enters the drainage network.
Axter's Aquamodul® Blue Roof system is designed to meet site-specific drainage requirements, and Axter provides technical calculations and advice to support planning and drainage strategies. The required performance depends on the individual site's planning conditions and drainage design.
Blue roofs require regular inspection to ensure that rainwater outlets and flow-control components remain clear and operate correctly.
Axter's Blue Roof Maintenance Guide recommends that an approved blue roof maintenance team reviews the roof every six months. Inspections include checking restrictor chambers, diffuser chambers and roof outlets, and removing debris or vegetation that could obstruct water flow.
A blue roof can provide rainwater attenuation within the roof or podium deck, potentially removing the need for separate below-ground attenuation storage.
Axter's Aquamodul® system is designed to use available roof space to help meet a development's SuDS requirements. Whether it can replace underground storage entirely depends on the site's required attenuation capacity, discharge limits and overall drainage strategy.
