Blue Roof feature

Blue Roof System

Roof Level Sustainable Drainage System

BlueRoof logo

A Radmat Blue Roof system is an effective means of providing a Sustainable Drainage solution (SuDS) in inner city and urban environments, in compliance with the requirements of the 2019 draft London Plan.

Storing water above the waterproofing layer a Radmat Geocell Blue roof system provides a method of regulated control to meet a limited discharge consent in accordance with SuDS design principles. Rainwater is held for no more than a 24-hour period from the end of the maximum designed rainfall event, and achieves half empty within a 12-hour period.

Designed to accommodate a 1 in 100-year storm event plus 40% climate change factor using FEH13 (Flood Estimation Handbook) data a Radmat Blue Roof system can be integrated within Radmat new build or refurbishment roofing systems and be incorporated in the Radmat System Warranty.

Radmat’s PermaQuik PQ6100 was the UK’s first waterproofing system BBA Certified for use in Blue Roof applications, enabling the specification of waterproofing, insulation, blue roof and green roof system from a single source.


Bloomberg European HQ

Located in the heart of Central London, Bloomberg L.P.’s stunning new European headquarters is now operational. Located in the heart of London between the Bank of England and St. Paul’s Cathedral, the building had to meet modern-day efficiency expectations while establishing itself as a notable visual icon within such constantly developing and advancing city.

Radmat and Prater were contracted to supply and deliver the installation of the waterproofing and thermal insulation to parts of the building, most notably its green/biodiverse roof.

The roof’s intricate design provided difficulties during insulation due to its tight spaces. Nevertheless, Radmat’s PermaQuik’s Hot Melt Monolithic Waterproofing Membrane; PQ6100, PQ2017, PQ2060/61, was an ideal solution as it combined excellent waterproofing performance with toughness, durability, flexibility and strong adhesion to a variety of substrates including zero falls. Its simple, hot melt installation process also provided ease and efficiency during application within the difficult access areas. The product is also BBA certified ‘for the design life of the building’.

The thermal requirements were also met with Radmat’s ProTherm G XPS X 300 SL and ProTherm G XPS X 500 SL, which was able to provide high-quality insulation while also conforming to the important efficiency targets.

It also performed in cancelling out the noise from the thriving city centre while preserving high acoustic quality inside the building, adhering to the required optimum aural levels.

Ultimately, Bloomberg’s New European HeadQuarter’s proved a success in serving as a productive visual splendour, while also adhering to and exceeding its efficiency targets, achieving a BREEAM sustainability assessment rating of ‘Outstanding’ with a 98.5%, the highest design-stage score ever achieved by any major office development.

Principal Place, Shoreditch

Radmat Building Products were contracted by Prater Ltd to provide a waterproofing and insulation system for Principal Place, a mixed use 600,000 sq ft development comprising of a 15-storey office building (home to Amazon HQ) 20,000 square foot of retail space and a 50-storey luxury residential tower (one of the largest residential buildings in London).

The development aimed to leave a minimal building footprint. This included careful planning regarding work and deliveries, ensuring congestion was as limited as possible with multiple trades onsite. However, one of the building’s main eco-friendly features were its green and brown roofing systems. This led to almost an acre of roof terraces complete with gardens being incorporated, meaning the standard of waterproofing had to be extremely durable to deal with more exposure to water.

Subsequently, Radmat’s PermaQuik PQ6100 Hot Melt Monolithic waterproofing membrane was chosen due to its BBA certification to last ‘the lifetime of the building’ along with its durability and compatibility with both green and brown roofing systems. PermaQuik PQ2017 Reinforcing Fabric and PQ2060/61 Detailing Membrane were also used to provide reinforcement for the 6100 system, ultimately delivering the highest and most robust standard of waterproofing.

Radmat’s ProTherm G XPS X 300 SL was the chosen roof insulation, due to its prestige standard of heating insulation, where it uses infra-red blocking particles to scatter and reflect heat radiation, meeting the thermal requirements. The ProTherm insulation was also an ideal choice due to its impressive sustainability standard, with a Zero Ozone Depletion Potential, a Global Warming Potential of less than 5, and a Green Guide to Specification A+ rating.

The Forge, Redclyffe Road

Formerly a bus depot bounded on two sides by existing residential developments, in 2014, Telford Homes acquired the land at Redclyffe Road in a swift unconditional purchase of the site without planning consent.

The scheme comprises of residential apartments clustered around communal courtyards, which are accessed off a new public street with substantial public realm enhancement. The new buildings range from three to five storeys with a 14-storey focal building.

Radmat was engaged together with RM_A Architects to design a roofing scheme to meet Newham Council’s strict attenuation and flow rate requirements. These requirements caused the development many challenges, the most pressing being meeting the strict run off limits imposed by the council across a geographically restricted site with reduced height zones. Due to this and close proximity to neighbouring properties, below ground attenuation had to be kept to a minimum, leaving the roofs and high level podiums as the key attenuation strategy. Radmat’s Blue Roof System had to be redesigned multiple times to meet the stringent attenuation targets, even utilising the ‘fingers’ of the roof to maximise the available space.

The development had to meet high thermal standards and provide as much amenity space to residents as possible while simultaneously providing extensive attenuation – the system build-ups were considerable, hence design heights at thresholds and parapets were compromised in some areas.

A series of inverted Blue Roofs were specified including PermaQuik Hot Melt Monolithic Membranes to provide a robust waterproofing, BBA certified for blue roofing applications and an independent durability statement for the design of the lifetime of the building. Radmat’s ProTherm Quantum Vacuum Insulated Panel System was installed in the most challenging areas, allowing the area to meet the thermal requirement in 80% less space compared to standard insulants, while still meeting the attenuation demands.

Finished with Radmat’s MedO Green Roof systems – both fully vegetated blankets for areas overlooked by apartments and seeded biodiverse roofs surrounding the PV panels – the roofs also incorporated ecological requirements for bio-diversity with different growing medium formulations and planting incorporated on different roofs. These habitat roofs have been included to promote environments that will support bees, butterflies and birds.

Gasholders, Kings Cross

Initially constructed 160 years ago, the newly restored Grade II listed Gasholder Triplets have been revived by Shepley Engineers, Yorkshire. As part of the Kings Cross Regeneration programme, the cast-iron structures have been re-housed to just north of Regent’s Canal. The original triplet frames have been re-purposed around a series of 1,2,3 and 4 bedroom apartment suites.

The apartments designed by WilkinsonEyre were constructed within the triplet structures, each including walkways interlinking one another. The apartments also bares its own roof garden. The suites were built in a circular structure, contained within the surrounding frames, and whilst pleasing to the eye, caused a number of difficulties within the construction process.

Radmat designed a bespoke roofing solution in order to fulfil the 153.7m2 walkway and roof garden, with a limited upstand height, to a U-Value requirement of 0.2W/m2K.

Thus, Radmat’s ProTherm Quantum PURE Vacuum Insulation Panels (VIP) system was chosen, accompanied by ProTherm XPS Infill Boards. As Quantum cannot be cut the XPS Infill was cut to shape to fit around penetrations and curved upstands. The VIP system was supplied over 5mm Regupol RCM to the external walkways and roof gardens providing a level threshold detail. It was also able to fill the space economically and overcome a complex roof shape, with a high number of pitch pockets. The insulation was versatile enough to overcome the challenging structure shapes while still delivering the best thermal and level threshold performance.

Quantum was the only BBA certified VIP Inverted Roof Insulation on the market able to meet the required U-value and maintain a 75mm waterproofing upstand for NHBC requirements. Radmat also provided a full site survey, bespoke layout design and installation support onsite.