Powerdeck F double - Gradient UK


Gradient’s turnkey service offering, in conjunction with high performance insulation, helped achieve the desired U-value performance on a highly challenging remodelling project at a private residence in London.

Ultra-thin vacuum insulation solution, Deck-VQ®, and Powerdeck® F boards supplied by Gradient, were a key requirement of a built-up insulation system installed as part of a refurbishment project in Wimbledon, south-west London. The owners of the large, detached property in Parkside Gardens required a solution for a flat roof within restricted build-up height to protect a building containing an indoor swimming pool. The 125m2 roof included low perimeter parapet walls. In these areas, it is essential insulation build-up is kept to a minimum to ensure the waterproofing isn’t compromised. Due to its minimal thickness and high thermal performance Deck-VQ®, which is produced by Gradient’s sister company Recticel, was selected as the ideal solution.

The Deck-VQ® vacuum insulation panel (VIP) is encapsulated to protect the Core-VQ at its centre, which has a market-leading 0.006 declared lambda value – the best performance on the market. This capability makes it the ideal insulation solution for flat roof and terrace applications where space is limited and material thickness is an issue, but high thermal performance is required.

The flat roof also featured 40mm-thick Powerdeck® F boards, which were used as infill panels within the insulation build-up. Powerdeck® F boards offer high-compressive strength and excellent thermal performance (λ = 0.024 – 0.026 W/mK). This ensures the flat surface finish required for optimum performance in a range of waterproofing systems in new-build and refurbishment projects.

For the Parkside Gardens project, the Deck-VQ® insulation panels and Powerdeck® F boards were installed by contractor Mulberry GBC Ltd on behalf of CC Construction, as part of a warm roof system, recommended by cold liquid-applied waterproofing manufacturer Triflex. As a partner of Gradient, Triflex had access to the company’s ‘one-stop-shop’, turnkey service. It meant Gradient’s technical teams were available at every stage of the project; from the initial consultation and design phase, through to installation and aftersales support. This close working relationship is seen as crucial to enabling Gradient to develop a bespoke single-layer roofing solution to suit a client’s precise requirements. 

This exceptional level of client support included Gradient working with Triflex to produce condensation risk analysis calculations prior to roof installation work starting in Parkside Gardens. With indoor swimming pools there is a higher level of humid, warm air within the room beneath the roof; therefore the analysis provided was essential to Gradient specifying the correct insulation type and thickness in order to eliminate the potential for surface and interstitial condensation.

Mark Gregory, Technical Manager at Triflex said: “Gradient’s expertise and attention to detail, in conjunction with the Deck-VQ® insulation panels and Powerdeck® F boards, were invaluable to the success of this project. From design to installation and thereafter, Gradient was with us every step of the way when it came to the roof’s installation. The company provides an all-round, first-class service.”

Easy to handle and install, the Deck-VQ® insulation panels and Powerdeck® F boards were key to the Parkside Gardens project’s completion. As part of the warm roof’s overall composition, they ensured the roof achieved a U-value of 0.18 W/m2K in accordance with Part L building regulations. The products, in conjunction with Gradient’s technical and customer service support throughout the project, guaranteed the roof met the required thermal performance and will remain protected against damp and ingress for many years to come.