Click to enlarge

Materials map - Clay

Unbaked earth and clay provided some of the cheapest forms of building material and were fairly widely used in England. In areas where stone was not readily available or difficult to quarry and expensive to transport and where there was no tradition of brickmaking it was the most useful form of material. Moreover, even in its unbaked form, earth can be incredibly durable if maintained in the right conditions. The nature of the material gives the walls a distinctively irregular appearance. They are also extremely thick, commonly up to 1.5m, with small openings which suits these buildings to the wet and windy climate.

Although cheap, wet earth as a building material was labour intensive to produce since most processes required mixing it with straw and small stones. This work was frequently done by cattle trampling the earth and straw together in a pen. The wet earth mixture was then built up in layers on a stone plinthGlossary Term. Each layer had to be allowed to dry, which meant that even humble buildings could take months to construct. A quicker process might be used in which the layers of wet earth, interspersed with straw, were built up in a single process but this tended to deform on drying out.

To protect it, the earth was washed with limewash or plaster and sheltered by the broad eavesGlossary Term of a thatch or slate roof. Where it has not been covered with render the colour of the walls vary with the colour of the local soil.

Some common forms of earthen building materials:

• Earth, chalk or gravel: compressed in wooden frames before drying into hard blocks.
• Turf: although the use of turf is uncommon in England, it could be cut into regular flat sections and built up in layers.
• Cob: a mixture of wet earth, lime and straw.
• Clay: either mixed with pebbles and straw or formed in moulds when wet.
• Clay lump: large blocks of clay, dried and assembled like bricks or stone in bonded courses. They can be distinguished from brick work however by their greater size.