Earth-Sheltered Housing

Earth-sheltered housing is a term commonly used to characterize residential structures enveloped by earth. This can take place in supraspace structures (above ground) covered by at least half a meter of earth mass or in below-ground locations. Similar terms indicate the degree to which the structure is beneath the earth.

Historically, earth-sheltered space is the most ancient type of habitat used by humankind. Almost every civilization has started with this form of living. Natural caves or human-made earth-sheltered structures continue to have varied uses, as they have for millennia. The most common use for earth-sheltered structures has been for their diurnal and seasonal sheltering from environmental extremes. They have been used for protection against extreme climates such as hot-dry (in the Sahara) or cold-dry (as in central Canada or central Siberia); for special storage, such as for grains or large quantities of water to minimize loss by evaporation; for irrigation canals (in Iran); for religious space to achieve tranquillity and ideal circumstances of contemplation; and for defense.

With the energy crisis of the 1970s, a rising interest in modern earth-sheltered space developed. The intentions are to use such space for all types of land uses, including residential, commercial, industrial, educational, and cultural centers.

Earth-sheltered habitats have been in use primarily, but not exclusively, in three large concentrations in the world. The first and largest are built into the loess soil of northern China, where an estimated 30 to 40 million people are still living in so-called human-made cave dwellings. Historically, this way of living has taken place for more than four millennia in China. The prime historical reasons for using this style of dwelling are to conserve the land for agricultural uses and to eliminate the need for building materials. The loess soil maintains itself firmly when it is free from water contact and high humidity.

The second major concentration of earth-sheltered dwellings is located in the northern Sahara desert bordering southern Tunisia, on the Matmata Plateau. Twenty-two communities still exist along this plateau. The most commonly known among them is the village of Matmata. The prime motivation for such usage is to protect the residents from the intense outdoor heat and to defend against invaders. This way of life has been in use by the Berber in North Africa for more than two millennia. This region is also characterized by semiarid to extreme arid conditions. The Romans, during their invasion of North Africa, used subsurface summer villas in the city of Bulla Regia located in northern Tunisia. This city region was the breadbasket of the Roman Empire. Both the Tunisians and the Chinese have used two types of earth-sheltered habitat (the pit and the cliff).

The third concentration of earth-sheltered housing is in Cappadocia at the center of the Turkish Plateau, some 400 kilometers southeast of Ankara, the modern capital of Turkey. Here, too, the climate is hot-dry in the summer and cold and partly snowy in the winter. As in the Chinese and the Tunisian cases, the dwellers practice the method of “cut and use” without the necessity of building materials. [Page 148]Earth-sheltered habitats in Cappadocia may have started in the second millennium BCE. There were two types of earth-sheltered construction: cliff dwellings and underground cities. The cliff dwellings were used almost continuously until the middle of the 20th century. The underground cities were probably used until around the 10th century CE. The cliff dwellings—and probably the underground sites also—were used by the Hittites, Greeks, Romans, and Byzantines. Geologically, the area is covered with volcanic tufa, which has been shaped by intense wind deflation and water erosion, creating pinnacles of relatively soft stone cones. Settlers cut into the cliffs of these cones and created an integrated nest of 8- to 10-story dwellings.

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