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Directory:Earth Bag Building Method

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Page first featured September 30, 2009

A view from inside an earth bag home whose walls/ceiling have not yet been grouted and finished.Courtesy http://CalEarth.org
A view from inside an earth bag home whose walls/ceiling have not yet been grouted and finished.
Courtesy http://CalEarth.org

The Earth Bag or Superadobe building method basically entails long bags of dirt from the building site laid in layers, forming arched structures for strength, so that the stacks serve as both the walls and roof of the structure. The wetted earth can either be compacted by pounding (rammed earth) to make it hard, or ~10% cement can be added with ~10% water so that the mixture hardens, with the bag providing the form. Cal-Earth sells 1-mile long lengths of both 22- and 18-inch wide bagging for a few thousand dollars. The bagging is cut to length, and then sewed shut with twine.

A good analogy of this construction method is the clay pot one might build in elementary school using rolls of clay, shaping it into a beehive type configuration, though there are a lot of other shapes that can be sturdy. Another common shape is a "barrel vault" or half pipe. The rolls of clay are 22 inches wide and 6 inches high.

The Superadobe technology (sandbag tubes and barbed wire) was designed and developed by architect Nader Khalili and Cal-Earth Institute, and engineered by P.J. Vittore. According to Cal-Earth, "Superadobe is a patented system (U.S. patent #5,934,027) freely put at the service of humanity and the environment. Licensing is required for commercial use."

If cement is used, the bags with earth harden in about four hours. Within a week, it would be advised to cut the channels for running electrical wire or conduit.

With the thick thermal mass walls (22-inches of earth), they help reduce heating and cooling bills. Also, their arch-based shape makes them very strong, exceeding the strength of most other structure types, making them ideal for seismic-prone areas, while also being more affordable (~$60/ft2) than most building types. Also the strength contributes to longevity. As the different rows are added to each other, they "become as one complete piece." Proponents say these buildings could last 500 to 1000 years. "They're monuments." The early models were run through third party testing by an engineering firm who placed 60,000 pounds of lateral pressure on top and did not detect a single failure.

They are usually finished off with grouting between rows of bags. Some kind of waterproofing needs to be put on the exterior, such as a rubberized coating. The final finish can be stucco, both on the inside and outside. The concept is also modular, so if the home needs to be expanded, another unit can be added on to it.

As of 2007, there were around 3,000 Earth Bag homes built around the world, ranging from Siberia to Costa Rica. Permits have been issued in U.S. states including: AZ, HI, CA, UT, NV, WA, KY; as well as in BC in Canada. Unless the code requires otherwise, the first row of bags can be placed right on the ground, without a footer.

They have been used in disaster relief, providing a rapid way to build a shelter of 120 - 200 square feet.

Speaking of disasters, the barbed wire rows in the walls, and the chicken wire mesh used in adhering the stucco, could conceivably serve as a partial farrady cage for protection from an EMP incident.

If water catchment is desired, a gutter can be built into the roof. A greenhouse can be built exterior to the south walls, with its roof butting into the structure via angle iron.

Contents

Key Websites

  • http://calearth.org - Non-profit organization set up to educate people about how to build using the Earth Bag technology. They also sell the Calearth mile-long bags, in either 22- or 18-inch widths.

Interviews

  • Stream | Download (12 Mb; mp3) - On Sept. 28, 2009, as part of the Free Energy Now radio show, Sterling D. Allan conducted a 1-hour live interview with Tim Hall, maker of several Earth Bag Homes, along with Mark Harmon from Cal Earth. They discussed how to build a home mostly from the dirt under your feet, mixed with ~10% concrete and 10% water, with a great deal of artistic freedom in wall shape; using arch construction, eliminating the need for a separate roof. Makes home building far more affordable and renewable.

Patents

United States Patent 5,934,027

Abstract 
The method of combining barbed wire and conventional bags to create structures includes the steps of: providing a plurality of bags; filling the bags with a predetermined mixture of organic, manufactured, recycled, particulate, fill material; stacking and arranging the bags in a predetermined array; and, placing at least one strand of barbed wire or similar wire between at least a major portion of the stacked layers of bags as they are being stacked to create frictional resistance to sliding between layers and tensile strength in a wall or other structure formed by the stacked layers of bags thereby to provide earthquake resistant structures. The structures include a building structure retaining wall, and an erosion resistant embankment for a body of water made by the method. The bags can be of different length, the fill material can include a cementious material thereby to create a permanent structure and one to three spaced apart strands of barbed wire can be used between layers of bags.

Individual Building Projects Using Earth Bags

In the News

  • Featured: Earth Bag > Communities > Safe Haven Villages > Blog >
    SHV Earth Tube Shed Construction Progress - The polypropylene tubing serves as a form to hold the dirt in place while it is shaped then tamped, then plaster is placed on the outside and inside to complete the structure, which is essentially an adobe type construction. We're testing terrazyme as a way to get tighter compacting of the soil. (Allan's Sustainable Home; June 22, 2010)
  • Building > Earth Bag > Sterling's Home > Blog >
    Dome-vault; "high tunnel" for winter building - Update on our home plans: "The earth bag walls go straight up with periodic buttresses along the horizontal length. At 8 feet up will be the floor joists, then the straight earth bag walls will end up another two feet. At that point will start the 10-foot radius concrete dome, which will have insulation around it." (Allan's Sustainable Home; Nov. 23, 2009)
  • Featured: Building > Earth Bag > Sterling's Home > Blog >
    Forms & guides for 20-foot wide parabolic earth bag vault - More correspondence with Owen Geiger, professional earth bag builder about cautions and mechanics of building. Also, some earlier correspondence in which I mull over the impossibility of building an earth bag home for my family of 6 in just one month in the Spring, then realize that I'll have to plan on purchasing the materials, then build. (Allan's Sustainable Home; Nov. 19, 2009)
  • Featured: Building > Earth Bag > Sterling's Home > Blog >
    2-floor Paramecium House Plans with Split Saircase - The Hot Dot House plan was a flop, partially because of heating issues, so the pendulum swung and we began considering a more traditional -- squarish earthbag -- floor plan; but then want back to the paramecium shap but with two floors and a nice split staircase, reading loft, some bottle walls. Normal doesn't work for us. (Allan's Sustainable Home; Nov. 10, 2009)
  • Featured: Building > Earth Bag > Sterling's Home > Blog >
    Revised House Plans & "Hot Dog House" Sketch - Energy status update. New floor plan posted with "phase I" and "phase II" to focus on a more doable portion within the budget and time frame we have to follow. The catenary vault portion is arched to withstand the back-fill forces. The sketch of the home, at least this version, resembles a hot dog. (Allan's Sustainable Home; Nov. 10, 2009)

Discussion

  • Examiner.com - feel free to view/post comments at our coverage there.
  • Discussion page here at PESWiki
  • A closely related method of construction is to compress bricks out of earth and use those as the construction material. Open Source Ecology has been a forerunner in developing, testing and describing a mechanical press for making bricks out of earth ([1]). Construction with those bricks can also achieve durable and pleasing structures as shown in CEB (Compressed Earth Brick) vault construction ([2])

Contact

Cal Earth

http://calearth.org/contact.html

Cal-Earth Inc./ Geltaftan Foundation
10177 Baldy Lane
Hesperia, California 92345
U.S.A.
tel: 760-956-7533
fax: 760-244-2201

Tim Hall

92-8327 Mamalahoa Hwy
Captain Cook, Hi 96704
phone: 808-854-1945
e-mail: TimHall@om1111.com

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