Medieval design could prove key to zero carbon living

The four-bedroom property, located near Staplehurst in Kent, is based around one large vault spanning 20 metres, covered on the outside with earth and plants. It was designed by architect Richard Hawkes. Michael Ramage, who is based at The University of Cambridge Department of Architecture, provided the structural design, along with Philip Cooper, who teaches in the department and is a director of ScottWilson Engineers.

The property, called Crossway, is currently more expensive to build than conventional properties because of the relatively high cost of the energy-saving technologies used in the build. But, say its designers, the simplicity of the design mean it is cost-effective and quick to build. This means that it could be a prototype for mass production of energy-efficient homes in the UK.

"The design is cost-effective in that the home is relatively simple to build and, once you know what you're doing, it's quick," said Rampage. "Many of the costs come from the new technology it uses for energy storage and generation. If those become more widely available, making a similar house cheaply in much larger quantities may be possible."

The Government wants all new homes to be zero carbon by 2016 and all UK homes to be carbon neutral by 2050 in order to meet its ambitious target to reduce C02 emissions by 80 per cent by the middle of the century. UK households currently contribute a quarter of all carbon emissions, but only a handful of homes are zero-carbon at the moment and many designs are too expensive to merit mass production.

The basic design of Crossway is adapted from an historic Mediterranean technique called 'timbre vaulting' and is a traditonal style mostly found in Catalonia, although the earliest known example dates back to 1382 in Valencia.

The timber vaulting uses thin bricks to create lightweight and durable buildings, while providing structural strength. It does not use energy-intensive materials, such as concrete, and the thermal mass it creates means the building reduces the need for central heating or cooling systems.

The energy-efficient technologies used in the building include the UK's first example of a combination photovoltaic and thermal heating system, an 11 kilowatt biomass boiler and insulation from recycled newspaper.

The build has also made use of locally-sourced materials, such as 'Kent peg' roof tiles.

"The building demonstrates how contemporary design can celebrate local materials and integrate new technologies to produce a highly sustainable building that sits lightly on the earth," commented Hawkes.