Scheme Summary
The scheme comprises 25 ultra low energy homes (12 flats and 13 houses) built on a brown field site. They offer affordable rents to residents and ensure reduced environmental impact in use. Environmental efficiency measures exceeded a SAP of 100 and it achieved BRE's Environmental Standard Award. Completed in 2000.
Scheme Details
The scheme was developed using the benefits of experience gained with the THERMIE project of 50 energy efficient homes at Amersham Road (see previous case study). It reused a derelict laundry site in a residential part of Reading. The scheme was developed as an Integrated Housing Initiative. This provides homes where both landlord and resident running costs are reduced, and where environmental performance is improved. This is achieved through increased levels of insulation, improved construction air- tightness, and improved water efficiency.
As part of the initiative the following issues were considered at the design stage:
- energy
efficiency - embodied and in use
- economical
water usage
- environmental
impact
- cost and life of building components.
Environmental Features
As with many brownfield sites contamination issues needed to be addressed.
Prefabricated foundations were used to save time on site mitigation works.
Pre-cast piles and ground beams with an extruded floor and 200mm of mineral
wool insulation were chosen over traditional piled foundations and cast
in situ ground beams.
A lightweight steel frame system from Forge- Llewellyn was used to enable fast erection times and allow high insulation levels to be added on site.
The roof is a pre-assembled steel frame with 200mm mineral wool insulation and 75mm mineral wool batts.
Internal partitions are constructed with 75mm non-structural partitions, which provide layout flexibility and allow for future re-arrangements.
The windows and rooflights are softwood frame with double glazed argon filled low emissivity glass. The steel frame enables the roof space to be used as habitable space. Sun Pipes provide natural lighting into internal staircases for flats. Dedicated low energy light fittings and bulbs are installed.
Rainwater recycling systems use ECOVAT underground rainwater storage containers. The water is used for WC flushing (6 litre) and in washing machines. This system also addressed site drainage capacity problems economically.
Insulation levels are so high that a traditional wet heating system is not required. Heat loads are reduced to less than 3kW and a heat recovery system is sufficient to heat the homes. Whole house mechanical ventilation, with heat recovery (MVHR) system is installed to all units. Heating costs are expected to be in the region of £30 per year.
A service zone contains electricity, gas, drainage and telecoms. connections. Rewiring is made easier by the use of trunking.
Porous blocks are used for hard landscaping, providing a sustainable urban drainage (SUDs) system.
Wheelie bin stores and recycling points are provided to encourage household waste reduction and recycling.
Costs
The scheme was built within the Housing Corporation TCI cost framework
with an overall build cost of £1,773,590 or £70,944/unit.
A detailed comparative cost exercise was carried out comparing the system with brick/block, timber frame and concrete. Although it was not the cheapest it was felt the innovations along with the speed of erection would make it competitive with the other alternatives. This proved to be the case. Although the properties cost in the region of £2-3,000 more to build than a standard brick and block scheme, given the vastly improved quality of the final product, it is considered to be a very competitive way to build sustainable homes.
Developer's Comments
Wilton Road was one of the first round Housing Forum Demonstration Projects to be approved and as such proved a valuable example of both the partnering approach (with contractor Llewellyn Construction) as well as of a sustainable urban development. Detailed monitoring of four of the MVHR systems are being undertaken for a 12 month period to establish real operating benefit. Already residents with asthmatic conditions have noted significant air quality and thermal comfort benefits.
The quality of the construction and the significant environmental benefits produced have combined to make this a highly successful flagship scheme for Ealing Family and Reading Borough Council.
Contact:
Ealing Family Housing Association,
St James' House,
105-113 Broadway,
West Ealing,
London W13 9BE
Tel: 020 8621 9841
Fax: 020 8840 9217