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IKO Elements blue roof systems

The IKO blue roof system provides an intelligent solution to incorporate attenuation capacity into green roofs or podium deck constructions. This supports sustainable urban development without the need for space-consuming ponds, retention basins, or huge underground storage tanks. The blue roof design combines a unified drainage and attenuation space within the roof structure, complemented by a roof outlet system aligned with site-specific planning consent.

This design empowers developers to achieve storage capacities with the ability to handle up to a one-in-a-hundred-year storm event, in addition to providing support for climate change allowance without compromising the aesthetic and functional qualities of the development. The stored water can be released at a controlled rate or used for greywater or irrigation purposes.

Want to know more about IKO Elements blue roof systems?

Our geocomposite drainage  system is a comprehensive and cost-effective solution to meet your storm-water attenuation requirements in roof construction.

The system’s filtered geotextiles and restrictor chambers provide a controlled dispersal of excess water from the roof surface and discharge through the roof outlet, following the site-specific regulations.

Our system offers numerous benefits, including reduced site disruption and excavation costs and storage within the building’s footprint—a massive advantage in densely urbanised areas.

Our restrictor chamber provides controlled discharge, making our system a reliable and affordable solution to manage your storm-water attenuation needs.

Why choose a blue roof?

Blue roofs help meet SuDS objectives by:

  • Controlling run-off ‘at source’
  • Providing storage volume
  • Improving water quality
  • Providing source control within the footprint
  • Valid part of the SuDS hierarchy and process chain
  • Contributes to the environmental credentials of the development
  • Installation issues reduced
  • Potential to reduce the number of roof penetrations and RWOs
  • Zero falls system
  • Waste to landfill reduced
  • Speed of site program improved
  • Quality of discharged water improved
  • Overall reduction in expected project costs

Design your blue roof

During the design process, IKO, in collaboration with our supply chain partner, will develop calculations to model the roof’s behaviour during storm events. This modelling takes into account essential factors such as:

  • Required discharge rates
  • Attenuation volume requirements
  • Time needed to complete discharge of attenuated water from the roof structure
  • Roof type
  • Design capacity
  • Structural considerations

Outlet design

Unlike traditional roof designs with excess outlets, a blue roof precisely calculates the number of restrictor chambers required to control water discharge. This often results in fewer outlets, reducing penetrations, detailing, and the risk of leaks. Fewer outlets also streamlines construction, reduces costs, and minimises service riser complexity.

Water quality

The blue roof system improves water quality by filtering out pollutants and particulates. It uses vegetation and geotextiles to ensure that water meets stage one standards for discharge into the river. The system’s treated water can be used for secondary purposes like irrigation and greywater reuse.

Waterproofing design

Proper waterproofing is essential. It is recommended that IKO Permatec monolithic bonded systems are used in conjunction with blue roofs. Regular testing of the waterproofing layer’s integrity is also recommended before the installation of blue roof components.

Access and maintenance

Compliance with standards is crucial, and access to the roof area is required for at least two annual inspections, taking into consideration the working at height regulations. Maintenance levels vary depending on the final finish. Proper attention should be given to blue roof elements, especially the outlets, which should be checked at least twice annually.

Thermal performance

To meet building regulations for thermal performance, insulation must be specified independently, as blue roof components are not considered part of the roof build-up for thermal calculations. As part of the roofing specification, IKO will incorporate this within the design.


Geographical factors like location, rainfall, and wind direction influence blue roof design. Vegetation selection for green roofs is also region-specific.

Final finishing

Blue roofs are compatible with various roof types, including extensive, intensive, biodiverse (brown), and paved or trafficked areas. Your choice of finish depends on project requirements, and IKO’s technical department can offer tailored design guidance.


Discover all the benefits of working with IKO and get in touch with your dedicated Area Business Manager today.