What is a Blue Roof?

- Fundamental to this guidance is the principal that a Blue Roof shouldn't be considered as a permanent water storage solution.
- A Blue Roof is a Flat Roof, designed to allow controlled attenuation of rainfall during heavy and storm events as part of a Sustainable Urban Drainage Systems (SuDS) good practice policy, replicating the natural environment or improving the as built environment.
- A Blue Roof will treat and release the water at a managed and controlled rate of the building directly into the sewers water ways and river systems.-
- A Blue Roof can incorporate other elements to create a useable multifunctional area. Incorporating green space which can be irrigated using the free storm water captured on the roof and amenity areas so that the building occupants can use the space.
- A Blue Roof can be created at either roof or podium level or by combining both in a cascade design above the waterproofing membrane in a warm roof application and above the water flow reducing layer (WFRL) in an inverted application, and should attenuate water for no more than a 24 hour period from the end of the maximum designed rainfall event.

Blue Roof Design Considerations

- The roof system must be installed with adequate falls for drainage all as per the BBA Certification, BS 6229 guidance & the NFRC Technical Guidance for Blue Roofs.
- Consideration should be given to the anticipated depths of collected water on the roof, specifically with reference to loadings & minimum 150mm upstand heights for the waterproofing.
- Consideration should be given to the drainage design, number and type of outlets, and location to ensure effective and efficient drainage of the roof.
- Ensure careful programming and project management to ensure the risk of damage is reduced (see Sarnafil HD section below) and the membrane is suitably protected during construction.
- The membrane should be carefully inspected and integrity tested prior to installation of any surface finishes or blue roof components.
- Regular maintenance programme is advisable.

Sarnafil HD - Waterproofing Solution for Flat Roofs

Sika Sarnafil’s single ply membrane is a strong, flexible PVC material which can be either mechanically fixed, fully adhered or ballasted. All joints are fusion welded via a hot air welding process.

Always looking to provide our customers with products that meet, and exceed, the demands of the market, the Sarnafil HD concept, promotes the use of thicker and more robust membranes. Sarnafil HD is a membrane particularly suited to tough conditions, making the 2mm think membrane ideal as the roofing element for your project.

Compatible Solutions - for Podium Decks

Sika’s years of experience in spray-applied Polyurea waterproofing have led to the development of the Sikalastic® range of products to offer you the best solution for your application. Sika’s Polyurea spray-applied systems are based on excellent technical properties for high performance applications. These materials are applied on prepared /primed external concrete surfaces by spraying and provide excellent solutions for complex detailing.

Permavoid is part of the Polypipe Water Management Solutions. Permavoid is a geo-cellular sub-base replacement system. The system has geotechnical properties at its core, allowing both store water for irrigation and attenuation through outlet flow control. It also provides a working platform that can be trafficked during and post construction protecting the waterproofing and insulation layers. The system allows the creation of spaces that can incorporate multifunctional benefits, such as green spaces, amenity and place making. Notwithstanding the core functionality of water management and making space for water. The Permavoid system has been extensively tested over the last decade to ensure that it meets the legislative requirements set out by CIRIA, the Environment Agency, SEPA and PPG.

Single Ply Roofing Materials