RAMMED-EARTH CONSTRUCTION

Rammed-earth construction is a technique used in the creation of a house. In its simplest form it involves dumping moist soil mixed with a small portion of clay into forms. The mixture is then rammed or compacted, it solidifies and the forms are removed. Rammed-earth construction is very common in arid regions where wood is in scare supply. One historical disadvantage of rammed-earth houses was their weakness to water. Freak rain storms could and do wash away rammed-earth villages in arid regions where rain is almost never experienced.

Modern rammed-earth homes are created using a combination of dirt mixture, re-bar, and styrofoam. The dirt mixture consists of clay, sand, and small gravel and is supplemented with ten percent cement. Regular footings are poured, the foam is placed to form a horizontal wall along the footing, re-bar is placed surrounding the foam, forms are built around the wall, and finally the mixture of clay, sand, gravel and cement is poured into the form layer by layer. Once the mixture is set the forms are removed and the wall is water sealed.

Houses build using the modern technique are one of the most environmentally friendly. Rammed-earth houses require a fraction of the 47 trees an average house built with stick-frame construction requires. The thermal mass and insulating properties of the rammed-earth walls reduce heating requirements far below the average dwelling. The thickness and density of the walls lends itself naturally to sound proofing and the materials used in the walls make them virtually fire-proof.

Reference: Western Living "earth to saltspring" October 2003.