Depending upon where we live on the earth, we will find different climates, as well as different resources and methods for building construction. Working with the tools, materials, and techniques most appropriate to the local area when we build our houses can save both money and energy. Rammed earth is one such building method, and one that is highly energy efficient.
- Rammed earth construction combines many of adobe’s best qualities. Soil from the site is mixed with proper proportions of clay, sand, water, and cement. The earth is then tamped into reusable forms to fill walls between concrete frames, foundations, and bond-beams, which tie the structure into an earthquake-resistant frame. If attention is paid to detailing at window and door openings, the rammed earth dwelling can have the same gracious and solid feeling as adobe, for less labor.
- Rammed earth walls contain tremendous thermal mass, so rammed earth homes are highly energy efficient. Further insulation may not be necessary, depending on your climate and site orientation.
- Think of rammed earth as a sort of “instant rock.” The earth rammer plies his trade in an environment filled with the dust of soil and cement, and the staccato thump, thump, thump of backfill tampers. Watching soil become stone beneath your feet is like magic. When the forms are removed, the well-built wall will survive the test of centuries.
- To make a strong and durable rammed earth wall, the soil should be a well-graded blend of different-sized particles. Large particles provide the bulk of the wall, while the smaller particles fill in the spaces. With every-decreasing particle sizes, virtually all of the air space within the wall can be eliminated, resulting in the densest wall possible. Density is one of the contributors to ultimate wall strength.