Building with Clay

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,

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.

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Building an earth oven

Building an earth oven

Mud is a near perfect building material. For thousands of years man has built ovens from mud. The best ovens in the smartest bakeries in the world today are often brick, which is made of kiln-fired mud.

Building an earth oven is not difficult and once it is ready for use, it can produce spectacular results – bread and pizza being very popular with teachers and pupils alike.

Oven fires are well-contained and quite safe as long as you use common sense and brief the pupils on safety issues. Oven fires are fuelled by wood, a relatively inexpensive and eco-friendly fuel.

What is ‘cob’?

Richard Gibson uses cob to make the earth oven and cob is a mixture of earth sub-soil mixed with sand and straw. This mixture naturally becomes very hard and durable, thus making a perfect material for the structure of the oven.

Locating an earth oven

It is advisable to spend a few moments considering where you will locate your earth oven, on the school premises. It is suggested that the ground should be roughly level where the earth oven is to situated. Also, endeavour to site the oven so that the door faces away from prevailing winds. And, of course, you will need to assess any possible fire hazards. It can also be helpful to take into consideration the proximity of the kitchen and water supply, although for the majority of schools these amenities are never far away as the grounds are usually not that vast.

The aesthetic design of the earth oven.

It is important to Richard Gibson that the aesthetic design of the earth oven is attractive and enthralling, as earth ovens are inherently sculptural. Mud is lovely to work with and the openings of the oven suggest all manner of real and mythical creatures. Some earth ovens become totemic structures, a house god or a piece of abstract art.

Pupils’ clothing

Stout boots or Wellington boots are the recommended footwear for pupils. Also, pupils should wear ‘old’ clothes, particularly old trousers as they will come into close contact with the cob. Pupils trample the cob underfoot in order to prepare it for use as a building material, on a large tarpaulin. This process emulates the traditional process of making cob which involved oxen trampling the muddy mixture. Indeed, pupils are involved at various stages of the earth oven building process.

Booking an earth oven building project.

Please contact, Richard Gibson, MA at or telephone 07967215745. Richard’s studio number is 01780 470447.

Clay workshops, art workshops, sculpture workshops, mural and mosaic projects are also available.

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