Stacks of dried out muddy-looking rectangles with a dirt smell and crumbly corners might be one way people imagine rammed-earth construction. However, centuries-old European homesteads, ancient Asian landmarks, and modern, sleek and efficient Western designs stand up against this stereotype. Crude forms of rammed-earth building in impoverished areas of the world do usually lack the polish of contemporary styles, but most share an amazing longevity and energy-efficiency.
Rammed-earth construction is simply the use of soil -- with a weighted mix of clay and sand -- packed super tight into brick form or packed up in layers within wooden molds to form walls. These blocks and walls are at minimum about 12 inches (30 centimeters) thick, but can be twice that, and they often have added external treatments to increase insulating properties and durability against weather extremes [source: Encyclopaedia Britannica]. Untreated walls are hardy too, but depending on the climate, modern techniques, such as moisture barriers or strengthened concrete mixes, can improve resilience.
Building a rammed-earth structure will lower energy consumption and costs, but due to the time, labor and transport involved, costs are much higher than in traditional homebuilding [source: California Energy Commission]. Working with local building codes for this unusual building type adds some work too, but long-term and possible lifelong energy savings in an Earth-friendly, earth-filled home may balance the initial time and costs.