Rammed earth
Rammed earth is a building method in which damp soil is compacted in successive layers inside temporary formwork to create solid walls.
Formwork: A temporary or permanent mold that holds material in place while it is shaped or set. It contains each lift of soil until compaction gives the wall enough stability to stand.
Adobe: A sun-dried building material made from earth mixed with water and often fibrous material. Unlike rammed earth, adobe walls are assembled from molded units rather than compacted in place.
Thermal mass: A material’s capacity to absorb, store, and release heat as its temperature changes. Dense rammed-earth walls can moderate indoor temperature swings by storing heat.
Great Wall of China: A system of fortifications built and rebuilt across northern China over many centuries. Some early sections used compacted earth, illustrating the method’s ancient use at monumental scale.
Concrete: A composite construction material made from binder, water, and aggregates that hardens into a stone-like mass. Concrete is commonly cast in formwork too, but relies on a hydraulic binder rather than compacted soil.
Soil compaction: The process of pressing soil particles closer together, reducing air spaces and increasing density. Repeated ramming densifies each layer and helps the finished wall resist loads and erosion.
Cob (building material): A building material formed from a workable mixture of subsoil, water, and fibrous reinforcement. Cob is shaped by hand in continuous masses, not compressed between formwork panels.
Passive solar building design: Building design that uses sunlight, shading, and thermal storage to regulate indoor conditions with little mechanical energy. Rammed earth’s thermal mass can support passive heating when paired with suitable orientation and glazing.
Alhambra: A palace and fortress complex in Granada, Spain, developed under Muslim rule from the thirteenth century onward. Its rammed-earth construction demonstrates the method’s refinement in historic architecture.
Compressed earth block: A masonry unit made by compressing moist soil in a mechanical press, with or without stabilizer. It uses compaction like rammed earth but produces separate blocks assembled into walls.