Building using earth (or subsoil) is one of the oldest construction techniques, providing simple shelter using freely available material. Buildings made from soil are found in many parts of the world, in different forms, sometimes mixed with other traditional construction materials such as timber or stone, or with more modern inventions such as cement and steel.

There are many ways of building with earth but two major methods are most frequently used; handmade unbaked bricks laid in mortar (adobe/compressed earth blocks) and compacted earth within a framework on site (rammed earth). Moist soil is formed either as a monolithic wall that is then allowed to dry, or into independent units, such as bricks or blocks, which are allowed to dry before being placed as a wall.

These styles have two common names. ‘Pise de terre’ or ‘Pise’ refers to a 19th century building style meaning ‘earth in place,’ and is now largely interchangeable with rammed earth. ‘Adobe’ is traced from the Middle Egyptian word ‘dj-b-t “mud [i.e., sun-dried] brick’ made from clay, soil and straw.

When constructing with adobe, the earth is first pressed into blocks and then dried before construction use. The advantage of adobe is that the blocks can be made, stored and used whenever needed. For example, the blocks could be made during spring or summer, in order to dry faster and apply surface treatment. They could then be stored to be used in the fall or winter. When building with rammed earth, the entire process, from determining the mixture to construction, is carried out in one go. However more recently there has been an increase in prefabricated rammed earth panels.

There are examples of both styles in the Middle East which date back to 8000 BC. One of the most impressive earth structures is the Great Wall of China. Throughout the world thousands of earth buildings over 500 years old are still in sound condition and inhabited. These can be found across the Middle-East, Asia and even into Europe. Currently it is estimated that up to half of the world’s population—approximately three billion people on six continents — lives or works in buildings constructed of earth.

Wherever suitable soil was available, people have developed a local earth building tradition. Even though earth is an ancient building material, the earth building tradition has been kept alive in many countries and the technology is constantly being adapted to the needs of modern civilization. Many assume that it’s only used for housing in poor rural areas—but there are examples of airports, embassies, hospitals, museums, and factories that are made of earth.

In the developing world, modern earth buildings have not caught on as it has in the developed world, possibly due to the long history of traditional earth buildings. As the middle class is growing at a fast pace in large parts of the developing world, previously impoverished families and individuals who have spent generations living in traditional earth homes will aspire to live in ‘modern’ houses built from concrete, steel and glass.