Earthbag Construction - Construction Method

Construction Method

The basic construction method usually begins by digging a trench down to undisturbed mineral subsoil. This trench can then be partially filled with cobble stones or gravel to create a rubble trench foundation. In high seismic risk regions a reinforced concrete footing or grade beam may be recommended.

Above that, several rows of doubled woven bags (or tubes) are filled with gravel and placed into the trench and one or two courses above grade to form a water-resistant foundation. Each successive layer will have one or two strands of barbed wire placed on top. This digs into the bag's weave and prevents slippage of subsequent layers, and also resists any tendency for the outward expansion of walls (especially with domes).

The next row of bags is offset by half a bag's width to form a staggered pattern. Bags can be pre-filled with material and hoisted up, or bags or tubes can be more simply filled in place. The weight of this earth-filled layer pushes down on the barbed wire strands, locking the bag in place on the row below. A light tamping of the bags or tubes serves to consolidate the moist clay-containing fill and creates interlocking bags or tubes of a strength between adobe and rammed earth. The same process continues layer upon layer, forming walls. A roof can be formed by gradually sloping the walls inward to construct a dome. Traditional types of roof can also be made.