Building with clay.
One of Richard Gibson’s enduring enthusiasms is his love of building, using a variety of clay-based materials. Here he discusses two varieties of building materials, with which he has worked. Richard shares this type of information with the pupils who attend his Claydayz workshops and they find it fascinating. Richard finds that the vast majority of children have never before considered the central importance that clay has played in the history and development of mankind through its use in pottery and building shelters and homes.
One traditional method of building was known as cob. The material cob is a combination of subsoil and chopped straw. It is traditionally mixed together by a team of oxen, each ox doing the equivalent work of about ten men. Interestingly, excrement which finds its way into the mix helps bind it together.
In Britain, cob housing is mainly found in Devon, parts of Dorset, South Hampshire, Wiltshire and parts of Cornwall due to the subsoil being of the appropriate clayey consistency. A variation on cob, called Wichert is also found in Buckinghamshire.
The walls are usually built on a stone foundation but if stone was not available then a plinth would be built from rubble.
Erected in courses or ‘lifts’, the height of one lift depended upon the width of the wall which was usually between 0.9 and 1.2 metres. Each lift was pitched up to a worker standing on the previous layer and trodden into place. A completed lift would be allowed to dry partially and settle for approximately one week before the next one was applied.
Another fascinating building material is called Pise de Terre (pise). Pise is thought to have first appeared in France around the mid-sixteenth century. The term applied to a method of constructing walls that were approximately 50 centimetres thick by ramming earth between parallel frames that would be removed to reveal a complete section of hard wall. As with cob, pise also was a building method that was prescribed by the materials found locally to the intended building site. Specifically, soils containing 50% of sand would be needed; silt was a valuable resource. Unlike cob no water was required as dry soil was rammed between the shuttering. Some images of sculptural work that Richard has undertaken in pise can be seen on his website, http://www.claydayz.co.uk.
Building with earth, although on a gradual decline, survived in Britain, Europe and other parts of the western world up until shortly after the Second World War. From the beginning of the twentieth century, steel, concrete and bricks began to take the place of earth but during difficult economic periods earth building would reappear.
Richard Gibson, on behalf of Claydayz, is frequently commissioned by schools to teach pupils all about how to build a clay oven, usually in cob, and the pupils take a very active part in preparing the materials and the sculptural design of the oven. These project workshops usually stretch over a 4 day period so that pupils can see the clay oven evolve. Following Richard’s input, most schools then use the oven on a regular basis to teach pupils more about sustainable sources of energy and how to cook nutritious, simple food. There is a growing number of Forest Schools attached to schools in Britain and clay oven building is very popular on these sites.