Scheme Summary

The scheme comprises a detached 3 bed demonstration EcoHouse. This was built to offer practical experience of energy efficient and environmentally sustainable construction. It has been awarded an Excellent EcoHomes rating. Completed 2000.


Scheme Details

The EcoHouse was developed in partnership with Brampton Rural Housing Society, Carlisle City Council and local architects, John Bodger and Stephen Crichton. The aim of the project was to design and build a house with significant environmental benefits, that was acceptable and affordable to residents, and easily replicable by small to medium scale builders or on a large scale.

An initial green specification was formulated, but proved too expensive. This specification was very green and it was recognised that compromise was necessary to achieve the project aims. The final specification was radically modified to include features that give the greatest environmental benefit for the least cost.

The project also aimed to raise environmental awareness within the building industry. Seminars and site visits were held during the design and construction phases of development.


Environmental Features

Consideration was given to two different construction techniques: high thermal mass brick and block work; and low thermal mass timber frame. Timber frame was chosen, using a timber I beam system with a breathing wall. The panels were insulated on site with blown cellulose (recycled newspaper). The possibility of using I beams to construct the roof, and provide additional useable space was rejected on budget grounds.

To remove the use of UPVc, softwood windows are used, with low emissivity double glazing. Rainwater goods are galvanised steel. The high level of insulation and airtightness reduce significantly the need for conventional heating. However, it was considered that in terms of acceptability, residents would perceive the need for a heating source. In response to this a small gas fired central heating system is installed.

Ventilation is provided by low energy conventional extractor fans to the kitchen and bathroom.

Both rainwater recycling and solar panels were considered. Payback periods were too long and alternative solutions provide more cost effective environmental savings. Low flow taps and shower head are fitted, along with low flush 6 litre WCs to help conserve water. Rainwater from the roof is collected in water butts for use in the garden, offering the option for residents to save more water. Low energy light fittings using CFLs are used throughout.

The building is part clad with reclaimed bricks, with upper levels being clad in low maintenance, sustainable timber (larch). The roof is covered in reclaimed Welsh slate.


Costs

The house cost around 68,500, plus fees. Although this appears to be relatively expensive, it is largely due to the house being:

  • A prototype
  • An individual detached house

If the house design was to be repeated on a larger scale, or incorporated into a terraced design, considerable cost savings could be made.


Developer's Comments

The process has shown that simple is best. The greatest environmental savings can be made in the building's basic structure, rather than the services or technology. It was quickly learnt that the initial house was over designed for its purpose (Mark 1). In trying to make every aspect as green as possible some features and systems that were inherently expensive, were built in. A re-think resulted in a more practical solution.

It is the first building to achieve an Excellent EcoHomes rating. Ironically the changes made between the expensive mark 1 design and the house built did not affect the EcoHomes rating. But it did ensure the house was more affordable and easily replicable. The problems of perceived difficulty should not be under estimated. Although building techniques are simple, builders' unfamiliarity with them raised time and cost concerns. This led to builders either not tendering or loading the costs.

Sustainable does not mean just choosing the right materials and designing for low energy use. To be genuinely sustainable the design of the house needs to be affordable and attractive to people who normally don't consider environmental matters important. It also has to make business sense as well as 'green' sense. In the end it was felt that the house design is viable in a business sense, as well as offering very significant energy savings and environmental benefits.

Contact: Judith Gibbons,
Cumbria Rural Housing Trust,
Unit 4B,
Redhill Business Park,
Penrith,
Cumbria CA11 0DT
Tel: 01768 242135
Fax: 01768 891726