Traditional cob houses are part of the country landscape in many parts of England and France. The traditional building method produces houses with a unique character – but they aren’t in line with modern energy efficiency standards.
French and British researchers under the leadership of Professor Steve Goodhew of the University of Plymouth, have developed a more energy-efficient form of cob that will use local materials, meet energy efficiency and structural standards, and be made using a more efficient, lower-cost process.
Project partners include the Ecole Superieure D’ingenieur des Travaux de la Construction de Caen (ESITC), Syndicat Mixte du Parc naturel régional des Marais du Cotentin et du Bessin (PnrMCB), Earth Building UK and Ireland (EBUKI) and the Université Caen-Normandie (UCn).
Successful Culmination of First Phase
During the first phase of the CobBauge project, 12 different soils and 6 different natural fiber varieties were combined to make 20 different formulations for evaluation. Two optimized mixtures – one for each of the two participating countries, was selected.
We had a very successful event in December to celebrate the end of Phase 1 of the CobBauge project. With a huge attendance of individuals from all areas of interest. The presentations from this event are now available from our website:https://t.co/dCm7dQSVS2@Channel_Manche #cob pic.twitter.com/Krmv7D2sab
— CobBauge Project (@CobBaugeProject) January 3, 2019
Then, innovative building methods were developed with the criterion for evaluation being a comparison between CobBauge and conventional building. The team aimed to keep costs and time needed in line with, or lower than those of a regular construction.
As the team approaches the March 2019 culmination of its first phase, it reports that it has developed the methods and materials that could be used to build hundreds of houses across England and France in the next ten years. The new way of building has been dubbed CobBauge – a combination of the English and French words for cob.
Thermally Efficient CobBauge Will Have Extra Environmental Benefits
To make cob more thermally efficient, researchers found that a dual-layered construction was better able to retain heat than traditional cob. It consists of a lightweight cob for insulation coated with a denser, stronger form that bonds the walls together. The University says that much of the work involved the analysis and measurement of different local soils’ and fibers’ thermal properties.
The research team says that its updated version of a traditional building material will not only allow for authentic restoration of landmark cob buildings, but also present the construction industry with a high-tech, cost-effective material it can rely on for energy efficiency.
In conventional construction, a great deal of waste is generated. The waste goes to landfills, placing further pressure on the environment and incurring significant costs. A CobBauge building will produce 16 tons less rubble per residential property saving an estimated €2115 in landfill costs.
What’s Next for CobBauge?
Researchers hope that CobBauge buildings will do well in these tests when compared to conventional building materials adding the attraction of healthier living to the advantages of CobBauge.
Apart from spreading the word about the new type of cob, researchers will continue looking at new cob formulations using non-traditional fibers from recycled materials. The team will investigate whether such fibers could result in a viable CobBauge mix.
The practical guidelines for building with the newly-developed cob materials will also be published, and it is hoped that construction industry professionals interested in the new technique will be able to receive training. There are hopes that this second phase of the CobBauge project will result in the construction of up to 1,500 buildings in England and France over the next decade.