Quebec Park in Bordon, East Hampshire, is a medium-size development of two, three and four-bedroom homes on the site of the old Quebec Barracks, and was the pilot site for the implementation of the Assured Performance Process.
The 100 homes on the Quebec Park site were designed to the Zero Carbon Homes standard and use a timber-frame construction, with additional rigid insulation inside the frame. Some units have photovoltaic panels on the roofs and there is a mixture of house types ranging from detached houses to flats.
Both the developer and design team have considerable previous experience of sustainable buildings. The developer, Radian Homes, has a number of developments that achieved Code for Sustainable Homes Levels 5 and 6 (with Level 6 theoretically a zero-carbon home).
Radian also carried out post-occupancy evaluations of these past projects, with lessons feeding into their new developments.
The Assured Performance Process included reviews of each house type planned for the site, at key stages of design, and construction. Using APP allowed a range of risks to be identified and mitigation measures implemented. A selection of these includes:
- Changing orientations to make it easier to provide summer shading and to maximise the output from the PV.
- Careful attention to the summer overheating risk (a particular risk for timber frame homes with low thermal mass), using shading and night-time ventilation to lower temperatures.
- Adopting better U-values than the minimum requirements of Part L of the Building Regulations.
- Multiple instances of reduced thermal bridging, and improved buildability of junction details.
- Multiple instances of changed site management and trades practices addressing key construction risk issues.
- Reducing boiler capacity to better suit heat losses and reduce boiler cycling, while reducing capital costs.
- Highlighting needs for clear accountabilities associated with energy, carbon, indoor air quality and overheating risk.
- Improving the clarity of handover documentation.
The in-use performance of the homes is now being assessed, and early results will be published when available.
“The National Energy Foundation provided an excellent service in supporting East Hampshire District Council to deliver its Green Town aspirations for the regeneration of Whitehill & Bordon. They helped us take another step along a journey in securing higher environmental standards for the town, specifically identifying activities which the Council could undertake with project partners to influence the planning and development process. I would recommend the National Energy Foundation to other local authorities wishing to take the lead on raising environmental standards within new and existing communities.”
Bruce Collinson, Environmental Sustainability Lead, Whitehill & Bordon Project, East Hampshire District Council
We have made regular visits to the site to examine energy related elements of the construction; checking on assembly of details, insulation type, thickness, and installation quality. We have advised on detailing and best practice to avoid thermal bypass and ensure thermal bridges are reduced as per the design intent.
We have also examined the timber fraction and made recommendations to reduce the risk of underperformance as the site build out progresses.
Developer: Radian Housing
Contractor: Drew Smith Ltd
Architects: Architecture PLB
Planning Authority: East Hampshire District Council
Energy Consultant: Greenbox Associates