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Earth Brick Building Catches On In Cold Climates
Adobe-style homes have always been popular in the Southwest U.S., but they've recently been gaining popularity in Wisconsin, Iowa and Minnesota. The up-front cost of Earth Block buildings isn't dirt cheap, but long-term benefits make them a better deal, says Dan Johnson, Midwest Earth Builders. Johnson has been building with earth bricks for 14 years.
"Earth block buildings are produced on site with local soils so less energy is used to produce, process and transport the materials," says Johnson. "That's important to a lot of my customers. Others just like the benefits of the solid buildings they provide. The earth bricks store and release heat when used in a passive solar design or with wood stoves. Plus they are fireproof."
Johnson adds that people also like them for the design capabilities. It's easy to build arches and curves, and they can be left exposed like a fired-brick wall or plastered with a wide variety of colors and looks.
"Earth bricks can be set in mortar like regular bricks, dry stacked in place like adobe, or stacked with the use of a clay slurry to seal them together," says Johnson. "All that's needed is the right soil consistency."
Too much sand causes the bricks to crumble, while too much clay will produce a brick that cracks as it dries. Johnson's ideal soil for earth bricks is 30 percent clay and 70 percent sand with no organic matter. Sand can be added if the available soil has a higher ratio of clay. If producing bricks for an exterior wall, he also adds either Portland cement or lime.
"There's no perfect soil as you always have some silt in it," he says. "If we don't have acceptable soil on site, we can usually find it nearby and haul it to the site."
Johnson uses a double action hydraulic press from EarthTek, Inc. to make uniform size and density bricks with square corners. The company recommends compressing the earth blocks at 2,300 psi, though that can vary depending on the raw materials.
Johnson has the second largest EarthTek block maker, which cost him $60,000. It can be operated by a single person, but is most efficient with two or three people, he says. The machine can produce up to 360, 4-in. high by 14-in. long by 2 to 10-in. wide blocks per hour.
EarthTek makes powered blenders for mixing sand and clay soils to get the right consistency and base for optimum bricks. Johnson uses a tractor with a rototiller to prepare the soil being used and to mix in additional sand, clay, lime or Portland cement as needed.
"What we are producing is an unfired brick," he says. "We always put a protective coating on the exterior whether stucco or even siding. In southern climates, you can just make the bricks and use them. In our area, I like to make them and cure them for about two weeks."
Earth brick construction uses the same foundations as other construction techniques. Johnson has used earth bricks for interior and exterior walls and interior only with stick-built exteriors. He has also used them for partial interior walls to absorb sunlight or heat from a wood stove.
Johnson notes that the only difference between earth brick construction and other styles is in the cost of the walls. Windows, roof, foundation and other costs remain the same. "It typically adds 3 to 4 percent to the total cost of a house," he says.
Contact: FARM SHOW Followup, Midwest Earth Builders, 51420 Johnstown Rd., Soldiers Grove, Wis. 54655 (ph 608 735-4595; cell 608 606-1170; midwestearthbuilders@yahoo.com; www.midwestearthbuilders.com) or EarthTek Inc., 318 Laurel Lane, Carrollton, Ga. 30116 (ph 505 362-2737; dan@adobemachine.com; www.adobemachine.com).

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2011 - Volume #35, Issue #4