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IKO Elements blue roof systems
The IKO blue roof system provides an intelligent solution to incorporate attenuation capacity into a variety of roofing systems. 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 meet the required attenuation allowances for their scheme – capable of managing up to a one-in-100-year storm event, including climate change allowances 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.
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What is a blue roof?
Blue roofs are a vital component of Sustainable Urban Drainage Systems (SuDS) – a design approach that manages rainfall in urban areas by mimicking natural drainage. SuDS aim to reduce flood risk, improve water quality and enhance biodiversity by slowing down and controlling the flow of rainwater. Blue roofs support this by providing an effective solution for stormwater management on flat roofs. Unlike traditional roofing systems, blue roofs are designed to temporarily store rainfall and release it at a controlled rate through restrictive flow outlets over a specified period – typically up to 48 hours – helping to ease pressure on urban drainage networks during peak rainfall events.
In today’s rapidly developing urban landscapes, blue roofs have become increasingly important, particularly in areas prone to flooding and with limited ground-based attenuation options. As part of UK planning conditions, large developments may be required to implement blue roofs, permeable paving or drainage ponds to meet sustainable drainage requirements. As climate change intensifies, urbanisation continues and regulations evolve, these innovative blue roof systems offer a practical approach to managing water where it falls, reducing the strain on conventional drainage systems.
Benefits of blue roof systems
Blue roofs play a crucial role in mitigating urban flooding through controlled stormwater management. By temporarily storing rainfall and releasing it gradually, they prevent sudden surges that can overwhelm drainage systems. This controlled approach helps reduce the risk of flash flooding, protecting both property and infrastructure.
When combined with green roofs, blue roof systems boost urban green spaces, contributing significantly to biodiversity. The integration of vegetation and water management creates habitats for insects, birds and other wildlife, encouraging ecological diversity in otherwise concrete-dominated environments.
Economic benefits
One of the primary advantages of blue roof systems is the reduction in the need for extensive ground-based drainage infrastructure. By managing water at its source – the roof – these systems reduce the requirement for costly underground storage tanks and extensive piping networks.
Blue roofs can also contribute to extending roof lifespan through improved water management. The controlled flow of water reduces wear on drainage systems and minimises potential water damage, ultimately leading to lower maintenance costs and longer roof life expectancy.
Regulatory compliance
Blue roofs are instrumental in meeting planning requirements that limit the flow rate of rainwater leaving a site. Many local authorities now specify maximum discharge rates and blue roofs provide an effective means of compliance while maximising the developable area of a site.
Additionally, blue roof systems contribute to achieving sustainability certifications such as BREEAM and LEED. These credentials not only demonstrate environmental responsibility but can also add value to properties and improve their marketability.
How does a blue roof work?
During a storm event, water is collected within the blue roof structure rather than immediately flowing to downpipes. This stored water is then discharged at a predetermined rate through flow-restricted outlets.
The controlled discharge rate, typically specified in litres per second per hectare, is carefully calculated to align with planning requirements and the capacity of local drainage systems. This controlled release continues for a specified period after rainfall has ceased, gradually emptying the storage capacity of the blue roof and preparing it for the next precipitation event.
The key elements of a blue roof system:
- Waterproofing membranes: high-performance waterproofing forms the foundation of a blue roof system, ensuring water is contained without leakage.
- Water retention layers: these components store the rainfall, often consisting of modular cells or drainage boards designed to hold specific volumes of water.
- Flow restrictors: these devices control the rate at which water is released from the roof, typically calibrated to meet site-specific discharge requirements.
- Drainage outlets: specially designed outlets work in conjunction with flow restrictors to ensure proper evacuation of stored water while preventing blockages.
Together, these components create an integrated system that effectively manages rainfall at the source, contributing to sustainable water management strategies.
Blue roof vs green roof
While both blue and green roofs contribute to sustainable building practices, they serve different functions. Blue roofs primarily support stormwater management, providing temporary storage and controlled release of rainfall. In contrast, green roofs prioritise the growth of vegetation, offering benefits such as thermal insulation, air quality improvement and biodiversity enhancement.
Blue roofs are engineered for water management efficiency and to optimise storage capacity and control discharge rates. Green roofs, while they also have some water retention capabilities, are structured to support plant life with growing layers of vegetation.
Blue-green roofs: Integrating both for sustainable roofing
The true power of sustainable roofing emerges when blue and green roof technologies are combined. These integrated systems, sometimes known as ‘blue-green roofs’, combine the water management capabilities of blue roofs with the ecological and aesthetic benefits of green roofs.
In a combined system, the blue roof components provide controlled water management, while some of the stored water is directed to support the vegetation of the green roof. When used together, they create multifunctional rooftops that address multiple sustainability objectives at once, from stormwater management to biodiversity enhancement and improved building thermal performance.
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Sustainable Roofing Specification
Blue roof installation
Things to consider when planning a blue roof installation:
- Structural load capacity: the building structure must safely support the additional weight of stored water, including consideration of maximum capacity and any additional loads.
- Waterproofing integrity: high-quality waterproofing is essential, requiring thorough testing before adding blue roof components.
- Maintenance access: adequate access is necessary for routine inspections, particularly of flow control devices.
- Discharge time: calculations must include the time needed to complete discharge of water, typically within 24-48 hours after rainfall.
Outlet design
Unlike traditional roof designs with multiple outlets, a blue roof precisely calculates the number of restrictor chambers required to control water discharge, typically resulting in fewer outlets, reducing penetrations and leak risks.
During design, IKO and its partners model the roof’s behaviour during storm events, accounting for discharge rates, attenuation requirements and structural considerations to determine optimal flow restrictor placement.
The blue roof system has the potential to improve water quality through filtration, making collected water suitable for secondary uses like irrigation. IKO Permatec LI inverted systems can be used for optimal waterproofing performance with added sustainability credentials.
The IKO Elements range
Green roofs
Environmentally friendly roofing solutions featuring layers of vegetation that improve air quality, provide insulation and enhance biodiversity. Available as extensive or intensive systems to suit varying structural requirements.
Solar PV roofs
Flat roofs provide ideal platforms for solar panel installations, offering highly effective solutions for sustainable energy generation and long-term cost savings through renewable electricity production.
Bio solar roofs
Combining green roof systems with solar PV technology, these innovative solutions boost both biodiversity and power output. The cooling effect of vegetation significantly enhances photovoltaic efficiency, increasing energy yields while supporting local ecosystems.
IKO’s blue roof solutions
Our comprehensive range
IKO blue roof solutions are part of the IKO Elements range, which was formed as part of our commitment to sustainable and environmentally responsible roofing.
Working with our trusted partners, we deliver complete end-to-end solutions that combine our industry-leading waterproofing expertise with specialist blue roof technology. This collaborative approach means you benefit from a single point of contact whilst receiving a turnkey service from specification through to installation and maintenance.
Waterprooofing: an essential foundation for long-term performance
All IKO Elements systems are supported by our high-performance waterproofing membranes, ensuring long-term protection and performance for your sustainable roofing solution.
IKO and LI: enhanced environmental credentials
As part of IKO’s commitment to sustainability, we’re striving to uphold ESG excellence in construction and manufacturing. Producing sustainable roofing systems with reduced upfront embodied carbon is one way in which we can contribute to meeting the UK’s carbon reduction goals.
Our innovative LI range of waterproofing, roofing and screeding solutions reduces embodied carbon, to add further environmental credentials to your blue roofing system. With up to 50% lower upfront embodied carbon, our IKO LI range is ideal for those wanting to further enhance their sustainability efforts, without compromising performance.
Discover how our IKO LI range can complement blue roofing systems by reducing embodied carbon.
IKO and ESG: journey to a more responsible future
There is a growing focus on environmental, social and governance (ESG) in construction and we fully support this movement towards positive change. Our latest ESG report highlights the progress we are making towards meeting our own objectives – from setting Science-Based Targets (SBTs) and producing sustainable roofing systems like blue roofs, to nurturing new talent and supporting the communities around us.
Let’s take another look at what we want to achieve by 2030:
- A 42% reduction in Scope 1 and 2 from our 2022 baseline.
- Certify 70% of IKO PLC (UK) suppliers are aligned with SBTi.
- Ensure 50% of all packaging is made up of recycled material.
- Make certain that 100% of raw material suppliers have a decarbonisation plan in place.
We have also pledged to achieve net-zero with a 90% reduction in Scope 1, 2 and 3 carbon emissions by 2050.
We’re proud of the progress we’ve made on our ESG and decarbonisation strategy but our work is far from over. We’re on a journey towards lasting, meaningful change. To learn more, read our Managing Director Anthony Carlyle’s blog on ESG at IKO.
Blue roofs FAQs
A blue roof is a roofing system specifically designed to temporarily store rainwater and release it at a controlled rate. Unlike traditional roofs that aim to remove water as quickly as possible, blue roofs intentionally retain water to reduce peak flow rates. As a key component of Sustainable Urban Drainage Systems (SuDS), a blue roof helps manage stormwater at source by mimicking natural drainage.
Blue roofs work by temporarily storing rainwater in special drainage layers on the roof surface. Flow restrictors control the discharge rate of this stored water, releasing it gradually over an extended period (typically 24-48 hours). This controlled release helps prevent overwhelming local drainage systems during intense rainfall events.
Blue roofs require regular inspection and maintenance, typically at least twice annually. Particular attention should be given to the outlets and flow restrictors to ensure they remain free from debris and function correctly. The specific maintenance regime will depend on the final finish of the roof (whether combined with green roof elements or used as a recreational space).
Blue roofs can be retrofitted to existing buildings but careful structural assessment is essential first. The existing structure must be capable of supporting the additional weight of stored water. In some cases, structural modifications may be necessary before installation can proceed. Each retrofit project requires individual evaluation by qualified structural engineers.
Blue roofs contribute significantly to sustainability by managing stormwater at source, reducing flood risk and potentially providing water for reuse. They help developments meet planning requirements for sustainable drainage and can contribute to BREEAM or LEED certification points. When combined with green roofs, they further enhance biodiversity and improve air quality.
While both contribute to sustainable building practices, green roofs primarily focus on supporting vegetation growth, providing insulation and enhancing biodiversity. Blue roofs focus on stormwater management through temporary storage and controlled release. The two systems can be combined into blue-green roofs to maximise both sets of benefits.
Beyond blue roofs, IKO offers a comprehensive range of sustainable roofing solutions through our IKO Elements portfolio, including green roofs, bio solar roofs (combining vegetation and solar panels) and our reduced upfront embodied carbon IKO LI range. All these options can be tailored to specific project requirements and sustainability goals.
We have ambitious targets in place, including achieving net-zero with a 90% reduction in Scope 1, 2 and 3 carbon emissions by 2050. As part of our commitment to meeting this goal, we have set Science-Based Targets (SBTs) and produce sustainable roofing systems, including green roofs and our IKO LI range of reduced upfront embodied carbon waterproofing, roofing and screeding solutions. Read our latest ESG report to see the progress we’ve made against our objective so far.
Transparency is key to driving sustainability in the construction and manufacturing industry. At IKO, we are committed to our ESG goals and have made significant progress, although there is still more to achieve. You can explore our journey and initiatives on our sustainability page.
Backed by IKO’s heritage and technical expertise, we are committed to supporting your blue roof projects with tailored solutions that stand the test of time. With transparent supply chains and a focus on environmentally responsible sourcing, we ensure that your roofing solution benefits both your project and the planet.
IKO Elements. Exceeding expectations, always.
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EXPERTS IN ROOFING, WATERPROOFING & INSULATION
Through our network of trusted sustainable roofing partners, we create bespoke sustainable roof packages designed to meet your specific needs –
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