earthen

Earthen describes anything made from or related to earth or soil. In construction and material science, earthen materials are mixtures of clay, sand, silt, and often organic binders such as straw; they may be used with or without stabilization. Earthen walls and floors rely on the properties of soil to regulate humidity and temperature, and they typically have low embodied energy when locally sourced.

Common techniques include adobe bricks (sun-dried clay bricks), rammed earth (soil compacted in formwork), cob (hand-formed earth and straw), pisé (rammed-earth used in Europe and parts of Asia), wattle and daub (a lattice coated with earth), and earth floors (pressed or tamped earth).

Benefits and considerations: earthen construction has low environmental impact and good thermal mass, helping regulate indoor climate. Surfaces are breathable, which aids moisture management but makes them vulnerable to water damage. Protective coatings such as lime plaster or cement-lime mixes, plus proper drainage and roof overhangs, are often required. In wetter climates, stabilization with small percentages of lime or cement can improve durability.

History and use: earthen construction is among the oldest building methods and remains widespread in many regions. Adobe and rammed-earth walls have deep traditions in the Americas, North Africa, the Middle East, and Asia. In recent decades, sustainable architecture has renewed interest in vernacular earth-building, with modern variants such as stabilized earth blocks and earthbags.