English Partnerships has gone out to tender for a housing development in Milton Keynes which it hopes will set a new standard for a sustainable suburb.
While traditionally suburbs have been seen as inherently unsustainable, EP’s aim with the housing scheme at Oxley Park is to test the viability of developing a sustainable suburban development, which, if successful, will be rolled out across other EP sites in Milton Keynes and beyond.
The brief sent out to developers in October for the 4.6 hectare site requires that environmental issues should be incorporated into the design, construction and management of the final development in order to achieve Ecohomes ‘excellent’ performance in a medium density scheme comprising 240 homes. “All of the developments on EP’s sites are built to Ecohomes ‘very good’. We now want to push the agenda further with this scheme and encourage a low-carbon lifestyle,” according to Graham Hyslop, senior regeneration manager in EP’s Milton Keynes office.
The brief says that EP’s objective is to create “a balanced community that provides an ecologically balanced meshing of built form and the environment.”
It sets a target of an average dwelling emission target of 18kgCO2/m2/yr which compares to an average UK of 40kgCO2/m2/yr. This can be attained through ensuring high levels of insulation and the use of renewable energy sources.
It says that active solar water heating should be “seen as the most simple and cost-effective renewable, both in terms of household ownership and replacement cost, maintenance and future upgrading.” Biomass heating or a ground source heat pump could be provided for at least 10% of the dwellings. Combined heat and power might be used.
The brief comments however that the “the amount of energy that can be sourced from renewable sources is limited by the size of the site and the low density at which the dwellings are to be provided.” It suggests that a minimum of 10% of energy use on site should come from renewable sources with a discretionary target of 20%. Fifty per cent of hot water requirements should come from annual hot water demand.
The concept of the sustainable suburb is “to re-establish the leafiness of the suburban neighbourhood. The design seeks to reestablish a relationship between the built form and the landscape so that much of the character of a street or neighbourhood can be determined by a response to the orientation, landform and ecology.”
It highlights the important role, which well designed landscapes can play in improving environmental performance of the scheme.
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Maximised enviromental performance
“Where dwellings are positioned to take advantage of passive solar gains, the orientation of the main glazed elevation and principal living rooms should be within 35 degrees of south with the incorporation of appropriate techniques for shading this elevation in summer to prevent over-heating.” Each cluster could provide a shared, communal structure that integrates bicycle storage, recycling, water collection and potentially some renewable energy generation.
Water consumption would be reduced through the use of water butts and water efficient appliances. Potable water consumption should be limited to 37m3/bedspace/year, compared to the UK average of 55m3/bedspace/year with an optional discretionary target of 32m3/bedspace/yr.
EP expects the development to appeal to those who are already committed to environmental sustainability but to put them on the right track, according to Hyslop. The brief is suggesting that the housebuilder should employ a ‘low-carbon champion’ for the first year after the development is fully occupied.
The champion would be part of the development team and could help set up a number of initiatives such as a car-pool scheme and shared composting facilities. “Eventually housebuilders could have a team that moved on from one scheme to the next helping the occupiers adopt low-carbon lifestyles,” he suggests.
Developers will be required to develop a landscape strategy which maximises the environmental performance of the development. The planting should provide solar shading in the summer to reduce the need for mechanical ventilation but permit solar gains to housing in the winter. Sufficient trees should be provided to filter pollutants from the air. The need to maximise solar gain, will affect the orientation of the building. The brief suggests a traditional perimeter block structure with three to four clusters of six to 12 homes.