Housing Associations and sustainable construction. Jenny Wain. Contents:

Prime Focus on prefabrication
- Watton Green

Scheme summary

11 houses have been constructed as part of the regeneration of the Castle Vale Estate, Birmingham. The scheme included a terrace of ten houses and one detached house that bring together innovative environmental construction and interesting design. Completed February 2001.

Scheme details

Focus worked closely with PCKO Architects to develop a timber framed sustainable development. The resulting scheme at Watton Green provides quality homes that break from the traditional brick homes ubiquitous to the Castle Vale Estate. Instead the properties introduce design interest and innovation to the estate. The development has achieved maximum SAP and hopes to secure and Excellent EcoHomes rating.

Working with Castle Vale Housing Action Trust and Castle Vale Community Housing Association, 11 families from the estate will be re-housed in comfortable, light, energy efficient and environment friendly new homes.

Environmental features

Using TRADIS pre-fabricated insulated wall panels and roof cassettes, an open plan shell was erected quickly. All internal walls are non load bearing to allow flexibility and adaptability to lifetime changes. This use of roof cassettes enabled the roof space to be used adding valuable working and storage area and an extra 10% of space standards. All timber is from a sustainable source.

The panels have high thermal performance, with cellulose insulation (recycled newspaper) well exceeding Building Regulations. The panels achieve U values of 0.19 and are foam and resin free.

The panel system provides interest in design as the structural components allow cantilevered structures to be incorporated producing overhanging and bridging features. Teamed with cedar cladding and coloured Trespa boards an interesting and distinctive street scene result.

The buildings’ orientation exploit passive solar gain. Windows of various sizes help reduce energy consumption, whilst adding design interest.

A central service core houses all necessary connections, natural ventilation ducts and sun pipes (providing natural daylighting to bathrooms). This enables easy access for servicing, maintenance and adds flexibility for internal layout design.

The homes are draught free. Passive ventilation (Passivent) systems will provide fresh air to the rooms and reduce the risk of condensation.
Water conservation features include 6 litre low flush WCs, showers over baths, aerated taps and water butts.
The houses have been built to Lifetime Homes standard to enable flexibility to accommodate residents throughout their lifetimes.

Costs

The overall scheme cost is expected to be in the region of £958,000, with an average unit cost of £87,000 or £692 per m².
Additional costs arising from the small scale purchasing of timber cassettes has been offset, to some extent, by savings on site from faster construction times and the use of fewer trades. PCKO designed the homes to maximise off site factory production methods that could be replicated in future developments.

Residents pay standard rents, ensuring the houses are affordable. The energy efficient design and construction offers the potential for substantial energy and water savings to be made by residents.

Developers comments

The overall scheme cost is expected to be in the region of £958,000, with an average unit cost of £87,000 or £692 per m2.
Additional costs arising from the small scale purchasing of timber cassettes has been offset, to some extent, by savings on site from faster construction times and the use of fewer trades. PCKO designed the homes to maximise off site factory production methods that could be replicated in future developments.

Residents pay standard rents, ensuring the houses are affordable. The energy efficient design and construction offers the potential for substantial energy and water savings to be made by residents.

Further information

Architects: PCKO Architects www.pcko.co.uk

Developers: Focus Housing Group www.focus.co.uk