Challenges of Earthbag Construction
Most of the challenges of building with earthbags have to do with the hoops you have to jump through before construction starts. Earthbag construction, because it is not widely known or used, poses some difficulties in dealing with building officials, banks and insurers.
Despite the structural testing conducted on earthbag homes, there is no mention of them in building codes, except in the city of Hesperia and in San Bernardino County in California, thanks to architect Nader Khalili's work with local building officials.
Outside of Hesperia, it will take a lot more work on the part of the person who wants an earthbag home. Earthbag construction has been primarily concentrated in Colorado, New Mexico and California [source: Barnes, Kang, Cao]. Many officials outside these areas might be unfamiliar with earthbag construction, requiring the loan applicant to provide the research. Many banks just aren't ready to take a chance on alternative construction, and dome structures are rarely financed by banks. Working with a smaller, independent bank that is more familiar with the area might yield better results than working with a bigger bank.
Still, even if a bank is interested, there might be other difficulties. Because earthbag housing is still rare, it will be difficult in many areas to find a comparable home, which is often the key to selling an unusual building method to a bank. A bank will use appraised values of comparable homes to set a base value for the loan applicant's home. If there are comparable homes, but they haven't been on the market in the past six to nine months, then they can't be used as comparable values. If an appraiser can't determine the value of the home, then banks can't give the money to build or buy it.
In terms of actually constructing the house, there are some limits on design. To remain structurally sound, earthbag homes are relatively small. For a domed earthbag home, 20 feet (6 m) is generally the recommended maximum diameter of the building [source: Hunter, Kiffmeyer]. Bigger structures can be accomplished by building a series of interconnected domes, or by extending underground.
To learn more about earthbag homes, see the links on the next page.