Gentoo Homes required a cavity closer and window solution that would help it meet Code Level 6 requirements on two properties in Durham.

Weighing up to 60kg each, the challenge posed was to devise a structural cavity closer that would allow the 0.8W/m²K U-value triple-glazed windows to sit over the 300mm cavity.

The walls had an overall thickness of 502mm with 300mm EPS bead filled cavity, which achieved a U-value of 0.10W/m²K.

The windows had to achieve Secured by Design standard.

Solution

Cavalok and its approved fabricator Securiframe worked with Gentoo to develop a structural cavity closer based on its BigBlok system.

This utilised new structural thermal materials, enabling the zero-carbon windows to be seated and fixed directly onto the main body of the closer, which eliminated the need for strapping back over large spans to inner structures.

In what represents a completely zero-carbon solution from Eurocell, Eurologik, which achieves a U-value of just 0.8 W/m²K, was specified alongside the cavity closer.

The architects at Gentoo orientated the windows to maximise use of solar energy transmittance, in line with Passivhaus principles. The 70 per cent light transmittance of the glazing enabled credits under the CSH to be gained for daylighting.

Client feedback
“We were delighted with the structural cavity closer and zero-carbon window solution from Eurocell,” said Verity Moss, Project Architect at Gentoo.

“One of the first challenges we had to overcome was supporting the triple glazed Eurologik 0.8W/m²k U-value window over the 300mm cavity. The only way this could be done was to make the cavity closer structural, and we were delighted that Cavalok was able to work with us to develop a solution based on its proven BigBlok system.”

Benefits
The Eurocell windows and Cavalok cavity closers play an important part in helping the three-bedroom Gentoo properties in Sunderland achieve Code Level 6 requirements, along with Secured by Design standards.

Initially developed as a bespoke solution for this project, the BigBlok structural cavity closer which, like all Cavalok products is the UK’s only BBA-approved 100 per cent post-consumer recycled PVC-U cavity closers, has now been introduced as part of the range.

The Eurologik 0.8 U-value window was launched in 2010 and continues to make use of post-consumer recycled PVC-U to create more affordable energy rated windows.