13. Earthen architecture
Earthen architecture can be defined as building where the main constructional material is unfired earth. Load-bearing walls, infilling of walls, roof structures, roof finishes and furniture can be constructed from earth.
Earth suitable for building is generally a well-graded subsoil with a good distribution of clay, silt, sand and aggregate. It should be noted that the clay component is essential for providing cohesion and plasticity during construction, and strength during service. The inevitable variation in subsoils including the moisture content has resulted in a number of manufacturing and construction techniques. This versatility of earth makes it possible to build with earth in cold wet climates such as Britain and hot dry climates such as Morocco.
Variations in soil types, diverse climatic conditions and a wide range of building techniques and numerous architectural details have resulted in culturally and geographically distinctive architecture. These differences are precious for the survival of local distinctiveness. To match this diversity earthen architecture has generated variation within its nomenclature. Clay, loam, soil, mud or earthen architecture are interchangeable terms used to describe the same type of building, where earth is the major constructional material. The name of the same construction techniques also differs from country to country and sometime across regions. For instance the earth building technique known as cob in Devon is called clom in South Wales, dob in Cornwall and witchert in Buckinghamshire, bauge in France, and
Figures & Tables
Concluding the trilogy on geological materials in construction by specially convened Geological Society working parties, this authoritative volume reviews many uses of clays, ranginf from simple fills to manufactured products. Comprehensive and international coverage is achieved by an expert team, including geologists, engineers and architects, who met over six years to produce the book. Packed with information prepared for a wide readership, this unique handbook is also copiously illustrated. The volume is dedicated to the memory of Professor Sir Alec Skempton.
Various definitions of ‘clay’ are explored. Clay mineralogy is described, plust the geological formation of clay deposits and their fundamental materials properties. World and British clay deposits are reviewed. New compositional data are provided for clay informations throughout the British stratigraphic column. Investigate techniques and interpretation are considered, ranging from site exploration to laboratory asessment of composition and engineering performance.
Major civil engineering applications are addressed, including earthworks, earthmoving and specialized roles utilizing clays. Traditional earthen building is included and shown to dominate construction in places. Clay-based construction materials are detailed, including bricks, ceramics and cements. The volume also includes a comprehensive glossary.