Cob is made with a mixture of clay, coarse sand, fine sand, silt and water, with a binder of fibrous or organic material such as straw or cow dung.
The word cob comes from an old English root meaning a lump or rounded mass.
It has been used for millennia even in the harsh climate of coastal towns. Thousands of cob homes in England, for instance, have been continuously occupied and now command very high market prices.
Building with cob follows a process of laying the cob balls in layers on top of the foundation walls, which are built of stone or fired bricks to around 200mm above ground level. The walls start wide at the base and taper in as one builds up. Each layer of cob must be allowed to dry before laying the next. Cob is fireproof and highly resistant to seismic activity.
Materials and Methodologies