New tricks with old bricks

The viable zero-carbon home built with traditional materials

The team discussing the concrete blocks

It’s the holy grail of UK housebuilding: how to build affordable zero-carbon homes in volume using conventional materials. Now, Britain’s housebuilders and housing associations can draw upon a blueprint for a zero-carbon home built using traditional masonry materials.

The Tarmac Homes project, a test-bed initiative led by Tarmac, affordable housing developer Lovell and The University of Nottingham’s Department of the Built Environment, has built two landmark homes – one to Level 4 and the other to Level 6 of the Code for Sustainable Homes – the Government’s zero-carbon target for all new homes by 2016.

Both properties are traditional, semi-detached homes built using brick and block materials to maximise their thermal efficiency. The finished zero-carbon property combines a super-insulated building envelope with a biomass boiler, a solar hot water system and additional photovoltaic panels on the roof.

The project, which also tested the commercial viability of building low and zero-carbon homes, provides the housing industry with an indication of the current costs to meet the Government’s residential carbon reduction targets.

According to the project findings, the Tarmac Code Level 4 home could be built for just £6,401.45 on top of the costs to build a typical home of this size - less than the industry figure of £9,000 per unit previously believed to be the additional build cost required to reach this level.

The Tarmac Code Level 6 zero-carbon home could be built for an additional cost of £37,762.95 per unit – a figure which suggests the previous industry estimate of a £31,000 for this type of property may need to be revised upwards.

Commenting on the importance of the project, Darren Waters, commercial executive director for Tarmac Building Products, said: “The Code for Sustainable Homes does not come with a set of instructions on the box to help housebuilders choose the correct mix of materials and renewable technologies to build a zero-carbon home. It was therefore important to use this test-bed project to try and develop a commercial house type which can be built using tried-and-tested products and techniques that have been favoured by UK builders for decades. This makes the initiative both practical and commercially viable.

The results of the project also provide the industry with an accurate financial indication of building low and zero-carbon homes. While it is good news for housebuilders in the medium-term that the costs for Code Level 4 are lower than previously expected, the higher costs of the Code Level 6 suggest that previous industry forecasts should be revised upwards,” said Waters.

Lovell regional director Noel Adams added: “This ground-breaking project has set out key lessons for the industry regarding the delivery of zero-carbon homes using masonry materials and traditional building techniques. Working on the scheme has been rewarding both for Lovell and our supply chain partners, who have been closely involved, and we look forward to building on its findings in the future.”

Dr Mark Gillott, associate professor at The University of Nottingham’s Department for the Built Environment, commented: “Researchers at the University will evaluate the performance of the homes once they are occupied. This is an essential part of the Creative Energy Homes research work – understanding if design aspirations are met once the homes are lived in. It is important that we understand if the stringent design measures actually work when put into practice.”

18 November 2009

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Fact 41

Solar hot water panels can provide 60% - 70% of your annual hot water needs.
Source: Self Build ABC