Alumasc Bluroof systems provide a single‑source, fully warranted waterproofing and sustainable drainage solution that attenuates and controls rainwater discharge for up to 48 hours. By releasing rainfall at a controlled rate, the system reduces peak discharge, easing pressure on local drainage networks and helping to minimise downstream flood risk. This delivers a more sustainable alternative to traditional drainage with potential cost savings over underground attenuation.
The key components include a flow-controlled rainwater outlet, a void former, and sufficient overflow capacity in case of blockage or storm events exceeding the design.
A blue roof is characterised by its ability to temporarily store water within a dedicated void space while maintaining full waterproofing integrity. Flow‑controlled outlets regulate discharge rates to meet the project’s SuDS requirements, and integrated overflow provisions ensure resilience during extreme rainfall or in the event of blockage. The void, typically created using engineered void formers, allows water to attenuate without affecting the performance or appearance of the overlying surface finishes.
Alumasc roofing systems offer complete integration and single‑source responsibility, supported by a single‑point warranty. This provides clients with clarity, accountability, and confidence in long‑term system performance as both are designed and warranted together.
A blue roof should be specified where controlled attenuation of rainfall is required as part of a site’s SuDS strategy, particularly on developments where ground‑level attenuation is limited or where space constraints make underground tanks impractical. It is ideally suited to urban environments, podium decks, and roofs where planners require reduction of peak discharge rates.
Blue roofs are commonly used in buried applications where projects aim to maximise usable roof space by combining stormwater attenuation with functional finishes such as green roofs, hard landscaping, or integrated solar systems.
Alumasc Bluroof systems are widely specified with Derbigum waterproofing membranes across warm, cold, and inverted roof constructions, and with Hydrotech MM6125 structural waterproofing for cold or inverted roof designs. Both systems carry BBA accreditation and are supported by Environmental Product Declarations (EPDs). Hydrotech MM6125 also benefits from European Technical Approval (ETA).
Alumasc provides a comprehensive range of single-source warranties for the Alumasc Bluroof system, offering coverage for up to 40 years. Installed exclusively by Registered Contractors and underpinned by our extensive project support service, these warranties cover product, workmanship, and design.
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