A fully certified Passivhaus scheme, using a Wetherby solid wall insulation system has seen the successful completion of 28 homes on this New Build development on the Isle of Wight.
Commissioned by Southern Housing Group, the project comprises 100% affordable units, including 16 houses and 12 apartments on a 1.5 acre site. The development for Southern Housing Group aimed to provide homes that are low on energy consumption, yet comfortable and healthy for residents to live in.
Isle of Wight Council are focussed on becoming the most sustainable local authority in the UK by 2020 and through their ‘Island Plan Core Strategy (2012 to 2027)’ aims for 1,790 new affordable housing units to be developed. The Cameron Close project has helped them towards achieving both objectives.
PCKO Architects carried out the design for this large Passivhaus rural housing scheme and have superseded the standard sustainability guidelines in the Code for Sustainable Homes and pursued further environmental developments by designing to Passivhaus standards. This was achieved by providing a building envelope with outstanding thermal performance as well as extreme air tightness to eliminate the loss of the heat through the building fabric and leaky junctions.
To achieve such Passivhaus standards it was of vital importance that a highly efficient external wall insulation system was specified for the building envelope and Wetherby’s Epsiwall system was deemed the perfect solution.
This particular scheme posed a number of challenges due to the unusually specified thickness of the insulation required. Since the Kingspan K5 phenolic board could not be supplied to the required 230mm thickness, the design detail had to be suitably adapted to ensure that Passivhaus standards were still being achieved. The architect’s final specification comprised of an initial layer of 110mm phenolic mechanically fixed using a 150mm insulation plug, followed by a secondary fix of 120mm insulation secured using a specially sourced 270mm fixing to ensure a firm anchor directly through into the property substrate.
Wetherby’s technical department had significant input into this scheme since naturally with this level of thickness of insulation, careful consideration had to be given to other key components of the system such as wider insulation base rails, specialist jointing pieces, trims and corner beads.
The system then comprised of Wetherby K&A basecoat with an alkali resistant scrim cloth embedded into the top third to offer a layer of strength/impact resistance. Since the architect envisaged a modern seamless finish to the new façades, the buildings were finish using a striking white Wetherby 1.5mm Silicone ‘K’ render.
The successful application of EWI has seen exceptional results which achieve finishing U-Values of 0.1 W/m2K.
This fully certified Passivhaus scheme has significantly enhanced the local environment, creating attractive streets and public spaces.