Adobe mud blocks are one of the oldest and most widely used building materials. The use of these sun-dried blocks dates back to 8000 B.C. (Houben and Guillard 994, referenced in EERI adobe tutorial). The use of adobe is very common in some of the world’s most hazard-prone regions, such as Latin America, Africa, the Indian subcontinent, and other parts of Asia, the Middle East, and southern Europe. Around 30% of the world’s population lives in earth-made construction (Houben and Guillard 994). Approximately 50% of the population in developing countries, including the majority of the rural population and at least 20% of the urban and suburban population, live in earthen dwellings (Houben and Guillard 994). By and large, mainly low-income rural populations use this type of construction.

Adobe is a low-cost, readily available construction material, usually manufactured by local communities. The typical cost of a new adobe house in Peru is about US$20/m2 (WHE Report 52, Peru) and US$/m2 in India (WHE Report 23, India). Adobe structures are generally self-made because the construction practice is simple and does not require additional energy resources. Often the blocks are made from local soil in a homeowner’s yard or nearby. Mud mortar is typically used between the blocks. Skilled technicians (engineers and architects) are generally not involved in this type of construction; hence the term, “non-engineered construction,” is used to describe the result. Worldwide use of adobe is mainly in rural areas, where houses are typically one story, 3 m high, with wall thicknesses ranging from 0.25 m to 0.80 m. In mountainous regions with steep hillsides, such as the Andes, houses can be up to three stories high. In parts of the Middle East, one finds that the roof of one house is used as the floor of the house above. Urban adobe houses are found in most developing countries. However, they are not permitted by building codes in countries like Argentina, or in specific cities like San Salvador due to their poor seismic behavior.