skilled task, although there are best practices for constructing dwellings. When compared to conventional building techniques, the skill level needed is much lower but the labor, or sweat level, is much higher. This means people with more time and energy than money can build an earthbag home and not have to hire a builder or contractor.
• Earthbags don’t have to be stacked in square or rectangle patterns and earthbag homes can be built in a large variety of shapes, such as domes and arches. Because of this, earthbag homes can be built without the need for a separate roof, as the walls can be corbelled inward to form the roof. No wooden or steel materials are necessary in the roof structure, saving both trees and the energy needed for manufacturing the steel or lumber.
• Earthbag homes can be built to provide either insulation or thermal mass, depending on the fill material. If the bags are filled with lighter materials, the walls are highly insulating. When filled with heavier materials, such as earth, the walls become thermal mass to store and dissipate heat for the house.
• The foundation of the building can also be built with earthbags filled with gravel, providing a non-wicking base for the structure in wet areas.
• Earthbag homes can be dirt cheap to build. The polypropylene bags are often available to purchase at a low price as misprints from the manufacturer, and even when purchased new they are quite a bit cheaper than other common building materials. Barbed wire and other necessary materials are readily available and low-cost.
The basics of earthbag building are quite simple. The polypropylene bags or tubes are filled with pre-moistened earth and laid up in a running bond (similar to bricklaying). The bags can be filled in place on the wall to eliminate most of the heavy lifting, and once the whole row has been laid, the bags are compacted with heavy tampers. Strands of 4-point barbed wire are then laid in between each course of earthbags, which holds the bags in place, in a kind of Velcro effect. The barbed wire adds strength to the walls, and allows the bags to be corbelled (stepped in) to form a dome. The doorways and window openings can be built around removable forms, enabling arches to be used for a strong structure.
Earthbag Building Innovators:
• An architect named Nader Khalili has been integral in popularizing the concept of building permanent structures with bags,
mixing the idea of adobe domes found in his country, Iran, with the earthbag building method. He refined the earthbag concept further by using strands of barbed wire between the layers of bags, which ties them together for stability. At first, Khalili filled his bags with desert sand, but then conceived the idea of the “superadobe”: bags or tubes of polypropylene filled with a moistened adobe-type earth that dries into a form of adobe bricks. Khalili’s institute in California, Cal-Earth
, The California Institute of Earth Art and Architecture, is a non-profit foundation now leading the world in earth architecture technology.
• Paulina Wojciechowska was a Khalili apprentice, and authored Building with Earth: A Guide to Flexible-Form Earthbag Construction
, as well as establishing a non-profit called Earth Hands and Houses
. The foundation supports building projects empowering indigenous peoples to build their own shelters using locally available natural materials, and it teaches workshops on natural building techniques.
• Other innovators in the earthbag movement are Kaki Hunter and Donald Kiffmeyer, who together wrote the exhaustive Earthbag Building book
. This is a valuable resource for earthbag builders, full of tips and tricks for learning the skills needed to create
Issue 2 | October 2009