Earth building techniques

Cob is just one of a number of earth building techniques that exist. We teach cob building on our workshops but we also cover wattle and daub during the course. And we talk you through rammed earth, clay-lump and adobe construction methods. We can also answer your questions on earth bag construction and other new earth building techniques which are gaining in popularity.

We chose to build our house out of cob as we felt is was the superior earth building technique due to the sculptural nature of cob, its load bearing credentials and it is also extremely easy to build with cob. And that’s why we love teaching cob building too – we believe anyone can learn to build with cob. You certainly don’t need any background in construction. In four days we can give you the experience, knowledge and confidence to go away and start building with cob.

Here’s a brief summary of each type of earth building that exists in the UK and around the world:

Cobcobb or clom (in Wales) is a natural building material made from subsoil, water, fibrous organic material (typically straw), and sometimes lime. The contents of subsoil naturally vary, and if it does not contain the right mixture it can be modified with sand or clay. Cob is fireproof, resistant to seismic activity, and uses low-cost materials. It can be used to create artistic and sculptural forms, and its use has been revived in recent years by the natural building and sustainability movements.

Wattle and daub is a composite building method used for making walls and buildings, in which a woven lattice of wooden strips called wattle is daubed with a sticky material usually made of some combination of wet soil, clay, sand, animal dung and straw. Wattle and daub has been used for at least 6,000 years and is still an important construction method in many parts of the world. Many historic buildings include wattle and daub construction, and the technique is becoming popular again in more developed areas as a low-impact sustainable building technique.

Adobe or Clay lump is a building material made from earth and organic materials. Adobe is Spanish for ‘mudbrick’, but in some English-speaking regions of Spanish heritage the term is used to refer to any kind of earthen construction. Most adobe buildings are similar in appearance to cob and rammed earth buildings. Adobe is among the earliest building materials, and is used throughout the world.

Rammed earth is a technique for constructing foundations, floors, and walls using natural raw materials such as earth, chalk, lime, or gravel. It is an ancient method that has been revived recently as a sustainable building method. Edifices formed of rammed earth are on every continent except Antarctica, in a range of environments including temperate, wet, semiarid desert, montane, and tropical regions. The availability of suitable soil and a building design appropriate for local climatic conditions are the factors that favour its use.

Earthbag building is a modern twist on perhaps humanity’s most important building tradition. Bags or tubes are filled with earth (a suitable aggregate, sometimes with additions, and if you’re really lucky it’ll just be the stuff you moved to make the site for your building), and then placed in walls; barbed wire is used as a tie or ‘mortar’, and the bags are ‘rammed’. Most often then, the earth cures, and makes solid walls which no longer rely on the bags or tubes for their integrity.