rammed earth, material consisting chiefly of soil of sufficiently stiff consistency that has been placed in forms and pounded down. It has been used for buildings and walls since ancient times and was employed in some of the most ancient fortifications in the Middle East. Pliny the Elder records the survival of a rammed-earth fort built by Hannibal 250 years earlier. The material has been recommended especially for subsistence homesteads and for farm buildings; it has been widely used in the Rhone valley. It is known in England by the French term pisé de terre. It is formed either into monolithic walls or into blocks, and in both forms it makes strong, durable walls with good insulating and fireproofing properties. Its resistance to water may be increased by stabilizing it with cement and by surfacing. Earth walls should rest on a foundation with a waterproof top and must be roofed immediately. The material usually costs nothing and does not require skilled labor. Adobe, unlike rammed earth, is sun-dried and is made without packing the earth down between forms. Cob and chalk mud are related building systems. The cob mixture consists of straw added to clay and water. It has been used in Japanese architecture and until recently was an important building material in some regions of Great Britain, particularly in Devonshire and South Wales. In the chalk-mud method, chalk is added to the earth and water. Sir Edwin Lutyens designed a monumental chalk building, Marsh Court in Hampshire, England.

Bibliography

See R. L. Patty and L. M. Minium, Rammed Earth Walls for Farm Buildings (1938); C. Williams-Ellis and J. and E. Eastwick-Field, Building in Cob, Pisé, and Stabilized Earth (1947).

rammed earth

or pisé de terre

Building material made by compacting and drying a stiff mixture of clay, sand or other aggregate, and water. It has been used by many civilizations. The most durable of the earth-building forms, it is formed into building blocks (see adobe) or rammed within removable wooden forms in layers or lifts to construct walls. China's Erligang (c. 1600 BC) is an example of a rammed-earth fortification; it covers an area of 1.2 sq mi (3.2 sq km) and may have taken 10,000 people more than 12 years to build.