Earthbag building (sometimes called sandbag building) is surely one of the lowest cost, most practical building methods. First used by the military for building durable, bullet and blast resistant structures, this building method has recently experienced a surge of interest among do-it-yourself builders. There are now an estimated 1,000 to 1,500 earthbag structures, including homes, offices, shops, schools, temples, clinics, orphanages and even ecovillages.
One of the strongest selling points is affordability. A simple earthbag dome, for example, using recycled grain bags and earth can be built for around $100. A larger, more comfortable home can be built for around $500-$1000. The EarthDome House at Terrasante Village in Tucson, Arizona is just one example.
Earthbags are ideal for owner-builders. The necessary skills for each step of construction can be learned in a few minutes. It boils down to simply filling bags with an appropriate fill material (typically subsoil or gravel) and tamping them solid. It doesn’t get much simpler than that. Also, few tools are required – shovels, buckets, garden hose. The few additional tools needed (tamper, slider) can be made cheaply and easily.
Earthbag buildings are sustainable since they are made primarily of earth from or near the building site. Earthbag domes do not require wood, thereby reducing pressure on our forests. Expensive concrete foundations are not required if you use gravel-filled bags. In addition, these structures are safe, quiet, nontoxic, rodent proof, and fire, hurricane and flood resistant.
Energy efficiency is another strong plus in favor of building with bags. The massive earth walls stabilize interior temperatures in hot climates. In cold and hot climates, earthbags can be filled with an insulating material, such as lava rock, pumice, vermiculite or perlite. Some builders are experimenting with rice hulls for insulation, which are often free for the taking. In general, lightweight insulating materials (such as those just mentioned) require far less labor than those of tamped earth and provide comfort through the harshest winters or hottest summers.
Earthbags can also be used to create underground (root/storm cellars, etc.) or earth-bermed structures, privacy and retaining walls, planters, furniture (built-in benches, etc.), and many other uses. Earthbags are very adaptable and work just as well for domes as they do for structures with vertical walls. They also excel at creating free-form, curving structures.
As earthbag building grows by leaps and bounds, NGOs and other organizations are exploring their use for emergency shelters. Millions of victims of wars and natural disasters need low cost housing and temporary shelter. More durable than tarps and more comfortable than tents, earthbags work perfectly since even unskilled workers can build their own shelters – all without destroying local resources.