How does the location affect the design of a rammed earth home?

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Formwork and Soil Mix Considerations When building a rammed earth home in a desert or arid climate, the formwork design must be adapted to accommodate the local soil conditions. For example, in areas with high sand content, the formwork should be designed to prevent sand from escaping and to ensure a stable base. A mix of 20% sand, 40% silt, and 40% clay is often used in arid regions, as it provides good stability and reduces water loss. The soil mix should also be designed to provide adequate thermal mass, with a minimum of 10% clay content to absorb and release heat.
Thermal Mass and Climate Considerations In arid climates, the thermal mass of the rammed earth walls is crucial to maintaining a comfortable indoor temperature. The walls should be designed to absorb and release heat, with a minimum thickness of 1.5 feet (457 mm) to provide sufficient thermal mass. In hot climates, the walls should be oriented to face north and south to reduce direct solar gain, while in cold climates, the walls should be oriented to face south to maximize passive solar heating.
Drainage and Water Management Drainage and water management are critical considerations in arid climates, where water loss can be significant. The design should include features such as a French drain system to prevent water from accumulating around the foundation, and a waterproofing membrane to prevent water from seeping into the walls. A minimum of 10% of the wall surface should be left exposed to allow for drainage and ventilation, reducing the risk of water accumulation and damage to the structure.