Housing Associations and sustainable construction. Jenny Wain. Contents:

Housing solutions and new technologies
- Greenfields - 1NTERGER

Scheme summary

The Greenfields scheme comprises 19 one bed flats (many with balconies), 6 two bed houses, 2 three bed houses, along with associated car parking, cycle storage and communal compost facilities. The scheme re-developed an under-used, vandal prone garage area. Completed 2001.

Scheme details

The homes were built following the principles of the 1NTEGER intelligent and green housing project. This project seeks to design homes that team environment friendly techniques and features with technology providing a more holistic approach to developing sustainable homes.

The Greenfields scheme was the largest 1NTEGER scheme of the time. It is designed to reduce the natural resource and energy in the construction process and for daily living. The houses will use up to 50% less energy and 30% water than a conventional house.

Environmental features

The buildings are orientated in a south westerly facing direction, with large areas of glazing to maximise passive solar gain. The rear, easterly elevations have smaller openings to minimise heat loss.

Space standards are above average:
Flats - 51 m²
2 bed houses - 79 m²
3 bed houses - 90 m²

The homes have a timber structure using I beam pre-fabricated wall panels (with pre-fitted glazed windows) and floor cassettes. All timber is from sustainably managed sources. The cassettes and panels are mounted on pre-cast concrete foundations.

Wall panels are insulated with cellulose (recycled newspaper) achieving U values of 0.2 (twice the level required by Building Regulations). Panels are clad in unstained Western Red Cedar. This has the benefit of being from a sustainable source and requiring low levels of maintenance.

Timber frame double glazed low emissivity coated windows, with a non-solvent stain are used throughout. A conservatory was also included as a heat buffer. This acts as a passive heat store, provides thermal heating and additional living/leisure space.

Low energy light fittings are included to reduce energy consumption.

The roofs are covered in sedum, a durable slow growing, low maintenance, alpine plant. The living green roof is rolled on top of mineral wool with an additional moisture retention layer that prevents the roof draining too quickly. The living roof not only reduces excess water runoff by 90%, it provides a micro-climate that humidifies and cools surrounding air. Water run off is collected for communal garden watering and stored underground.

An additional roof feature includes a ‘solar upstand’. This is constructed at an angle that optimises solar gain, with minimal shadowing from obstructions. Solar water panels and photovoltaic panels are mounted here which further reduce the running costs of the homes.

Passive stack ventilation provides an effective and energy efficient way of maintaining fresh air and removing smells and moisture without the need for electric fans.

Along with low flush WCs and other water saving appliances, grey water recycling is installed. Water from baths, showers and wash basins is recycled to flush WCs.

To reduce waste and construction times, factory constructed bathroom and kitchen pods were installed around a central service core. The pods are in essence factory produced ‘rooms’ containing all fixtures, finishes and floorings ready to be added to the structure. Clear service paths for wiring/heating pipes are designed for easy access, maintenance and attention.

The homes have multiple provision of TV, telephone, cable and data points to facilitate home working. The aim is for technology to help deliver sustainable communities.

Costs

The £2 million project cost around 10% more than a conventional scheme. This was jointly funded by the Royal Borough of Windsor and Maidenhead, the Housing Corporation with Social Housing Grant. The Department of Trade and Industry Renewable Energy Programme provided funding for the photovoltaic installations.

Savings to tenants are anticipated to be in the region of 50% for energy consumption and 30% for water consumption.
Monitoring is taking place to establish savings in use.

Developers comments

As a housing association providing homes for rent to people on low incomes it is important that we try to keep the running costs of homes as low as possible as well as rents. This scheme should reduce gas, water and electric bills by up to a half so improving our tenants’ quality of life. Additionally the cable and data links within the scheme will help our tenants join the information age.

As a pioneering project in prefabricated timber construction with all of the energy saving measures, costs have been higher than traditional designs. However lessons learnt from this project in terms of design and sub contract assembly packages lead us to believe that the next project will achieve build rates below the industry norm.

As a movement housing associations are major consumers of raw materials and energy. The sustainable construction methods and materials employed on this project together with low energy consumption in use point toward the future of sustainable construction.

Further information

Developers: 1nteger: www.integerproject.co.uk