The Kingspan TEK® Building System and Kingspan TEK® Cladding Panels have been installed, along with several products from Kingspan Insulation’s premium performance Kooltherm K-range, on London’s largest Passivhaus development.
Developers, Octavia Housing, appointed Cartwright Pickard to design The Greenhauses in Sulgrave Gardens. The site comprises a row of three-storey terraces (Block A), two five-storey apartment buildings (Blocks B & C) and a further four mews houses with roof terraces (Block D). Both Blocks A and B have now been fully Passivhaus certified.
Main contractors Durkan oversaw construction on the project and to complement the architecture in two adjacent conservation zones, brick was chosen as the primary façade material for the buildings. Given the tight, urban nature of the site, minimising the thickness of the remaining wall build-ups, whilst still attaining the required level of thermal performance, was a key objective.
To achieve this, the Kingspan TEK® Building System was specified for the external walls of Block A and D and Kingspan TEK® Cladding Panels were installed on the concrete frame of Blocks C and D. Both products were designed and pre-cut to the project’s requirements by Kingspan Timber Solutions, ensuring a predictable installation with minimal on-site waste.
On Block A, a breather membrane was stapled to the outer face of the Kingspan TEK® Building System, followed by 90 mm thick Kingspan Kooltherm K12 Framing Board. A 50mm cavity was then left between the build-up and the 102.5mm brickwork facing. Internally an airtight membrane was taped to the Kingspan TEK® Building System’s face, followed with a 25mm service zone and two 15mm layers of plasterboard lining.
The Kingspan TEK® Cladding Panels installed on Block B were fixed to the concrete floor slab using angled cleats. The build-up mirrored those in Block A with the airtight membrane sealed to the concrete frame and soffits with airtight tape. The aluminium composite façades used in certain areas of the exterior were installed on aluminium brackets fixed to timber battens.
Both build-up’s achieved outstanding thermal performance with final external wall U-values of 0.10 W/m2.K. Two 100 mm layers of Kingspan Kooltherm K3 Floorboard were also installed on the ground floors of all four blocks, matching the thermal performance of the external walls.
The proprietary jointing system featured on both Kingspan TEK® products, in combination with the additional airtightness detailing on the project, ensured that air loss from the blocks is below the 0.6 air changes per hour @ 50 Pa. To maintain a constant flow of fresh air, mechanical ventilation heat recovery (MVHR) systems were installed in all of the blocks, using heat from the outgoing, stale air to warm the incoming, fresh air.
Grahame Hindes, Chief Executive of Octavia said:
“Sulgrave Gardens provides 30 stunning new homes made available to individuals on all incomes – including 8 for outright private sale, 13 for shared ownership and 9 for affordable rent. We wanted to provide energy efficient homes to individuals and families on all incomes. On average these homes are anticipated to make significant savings on fuel bills (up to 90% in the case of the certified units) and they offer significantly improved air quality within. Octavia are very proud of this award-wining scheme.”
James Pickard, Director of Cartwright Pickard commented:
“We are proud to have worked with Octavia to deliver the largest certified Passivhaus scheme in London, proving that Passivhaus dwellings are a viable proposition in urban locations that might previously have been deemed unsuitable. The brick finish and careful detailing demonstrates that eco-homes can be attractive, and don’t have to look idiosyncratic or incongruous.”
“As a practice we have always been interested in pushing the practical application of new technologies to create better buildings. Our prefabrication and lean design expertise was invaluable when dealing with the enhanced thermal and air tightness requirements on this project. We’re currently undertaking building performance evaluation and occupier wellbeing, and will be monitoring these dwellings as part of that.”
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