Cal-Earth Superadobes
The California Institute of Earth Art and Architecture is a charitable non-profit organization that was founded in 1986 by Nader Khalili (1936-2008). They focus on developing truly sustainable earthen architecture. Their primary building method, nicknamed superadobes, uses long sandbag tubes filled with a semi-moist mixture of earth, cement, and water. The rows are laid with barbed wire between the sandbags in a similar fashion to other methods of earthbag construction.
I’m not sure how this method compares with building with sack-size earthbags. The inclusion of cement in the earthen mix must give the walls some added water resistance, but even unstabilized adobe bricks can hold up to years of weathering, and centuries if protected from direct rain. In any event, if you’re considering building an earthen building, here is yet another way to build with the stuff under our feet. Learn more on the Cal-Earth website.
How does it compare? I think it’s largely a matter of opinion and/or using the most readily available materials. Tubes may be faster, but they’re more difficult to obtain and often more expensive. Poly bags are everywhere and often available recycled. Only buy strong bags in good condition that have been stored out of sunlight. Make a sample earthbag before buying.