Gradient Wilderton Road Tapered Insulation

Gradient’s design expertise was crucial to the supply of a non-standard tapered insulation system that ensured a private dwelling’s roof exceeded regulation U-values.

The roof installation was a crucial element of a property under construction in Poole, Dorset. The five-bedroom detached home is imaginatively designed with Purbeck natural stone walls and an aluminium facia. For its 500m2 flat roof, the client required bespoke insulation that optimised water run-off whilst achieving regulation thermal performance. This led to engagement with Gradient, on account of the company’s expertise in specifying and designing a tapered roof insulation scheme to suit a client’s precise requirements, however complex the brief.

For the Poole new-build project, Gradient devised a fully-bonded tapered single-layer system comprising Powerdeck® F boards. Produced by Gradient’s sister company, Recticel Insulation, Powerdeck® F boards offer excellent thermal performance, whilst their high-compressive strength and dimensional stability ensure a supremely flat surface finish. This guarantees an optimal outcome for a range of watertight systems in new-build and refurbishment projects.

The single-layer aspect of the Poole tapered insulation scheme was essential to its time and cost-effective installation. Manufactured off-site under factory conditions and ready to install once delivered to site, the insulation within a single-layer bond is monitored by Gradient for its volume and minimum coating adhesion performance, leaving installers with the relatively straightforward task of installing it – in one block – to the roof, followed by the waterproofing. This not only guarantees the insulation will perform as-designed in concert with the single-layer roofing membrane details, it significantly reduces application times and material waste.

The single-layer system designed for the Poole residential project needed to accommodate a range of complex details. These included centrepiece and perimeter guttering, a non-standard detail that was designed to direct rainwater to the correct falls and ensure efficient run-off. Mansafe railing and PV panels were also incorporated within the single-layer scheme, which was designed to a 1:60 and 1:80 fall.

Contractors, All Roofing Ltd, installed Gradient’s tapered insulation scheme to the detached property’s roof. It was fully-bonded to a vapour control layer with the same procedure being carried out across three, first floor balconies. Prior to installation and proof of how Gradient’s turnkey service supports clients throughout all phases of its tapered insulation delivery, the company’s surveying team visited the construction site in Poole to carry out a full survey of the roof. This contributed to their specification of a suitable tapered insulation system, thus ensuring a smooth installation process and enshrining the insulation’s long-term performance.

Scott Strathem, Director at All Roofing, said: “Gradient’s involvement meant this large and quite complex project ran very smoothly. And as we’ve come to expect, they were with us every step of the way throughout the programme. As well as their superb design detail, their pre-installation survey of the roof was particularly beneficial in giving us the peace of mind that it was fit for the single-layer system they’d provided. We’d always advise engaging with tapered insulation experts such as Gradient before embarking on a flat roofing project of any type.”

The main roof in respect of the Poole residential project was installed in less than four weeks. The client’s satisfaction with the rapid works programme was enhanced by the in-situ roof achieving a U-value of 0.16 W/m²K, thus exceeding regulations which applied at the time. Gradient’s expert provision of a tapered insulation solution that was tailormade to overcome the complexities of the scheme will reduce the need for further roof maintenance and uphold the building’s thermal energy performance. Such an outcome demonstrates why engaging with professionals pays dividends when it comes to insulating a property’s most vital feature.