Timber frame houses built from insulated panels constructed off site and craned into place will form the backbone of the UK's first zero carbon eco town, North West Bicester. Lead developer A2Dominion, and main housing contractor Willmott Dixon selected the Sigma II system from Stewart Milne Timber Systems for the pioneering development. The company will provide highly-sustainable timber frame houses as part of the UK's only eco town still to adhere to the previous Labour government's original Eco Town Policy Planning Statement designed to achieve high standards of environmental sustainability. The initial phase of the scheme will provide 393 homes, which meet the Code for Sustainable Homes Level 5. Each home will have a true zero carbon rating, with heat and hot water being generated on-site by a highly efficient, gas-fired combined heat and power plant. The development will also feature the UKs largest domestic solar panel array, with 17,500m2 mounted across the rooftops of all homes to generate electricity. This includes freestanding photovoltaic (PV) panels, overlaid PV panels and inset PV tiles. The homes at NW Bicester are designed to be 'future proofed' against climate change and rising temperatures. Some homes also have future-adaptable roofs, which can be transformed with ease into increased working or living space to improve the life cycle of the buildings and reduce travel requirements. Aiding the energy efficiency is the type of wall being used to construct the homes, the 195 C-Stud. The system delivers a U-value of 0.15W/m2K through the external walls, and 0.13W/m2K through the roof. The external walls will also have a PSi value of 0.04W/m2K, which is achieved through the unique C-Stud, ensuring minimal member cross section between the external and internal sections of the panel. The project's airtightness will be 3m3/hm2 @ 50pa, which will be tested after the erection of the timber frame and before the handover of each plot. Airtightness in the external walls is achieved within the panel itself, rather than at a site fit level, allowing a higher quality of finish. The party walls and roof will be site insulated and made airtight with membranes. This, along with pre-assembled roof modules and insulated floor cassette edges, means a pair of semi-detached homes can be weathertight, airtight, secure and fully insulated within 72 hours, providing a safe and efficient means to complete the homes on site.
