Earth Bag construction is a free form version of rammed earth. Since the bags act as a flexible form, it allows the architectural design of curvaceous, sensual, monolithic structures. We have the ability to mold, bend, writhe and swoop scultural forms inspired by nature's artistic freedom of expression, while providing profound structural integrity. hence a whole house from foundation to walls to roof can be built using the Earth Bag technique.
The proceedure is simple. The bags are filled with moistened dirt right on the wall being built, laid in a mason style "running bond." We use #10 coffee cans for scooping and filling. This eliminates any heavy lifting. After a row of bags is laid, the row is rammed with hand tampers. Between every course is laid 2 strands of 4 point barbed wire that acts as a velcro mortar cinching the bags in place. This allows for the rows to be stepped in to create self supporting corbelled domes and other unusual shapes. Arched window and doorways are built with the removable plywood form until the keystone bags are tamped in place. Voila.
The bags we used for our construction are woven polypropylene "misprints." The companies that manufacture these bags sometimes have imperfections or mistakes in the printing prcess that render them unsuitable to their clients.
Rather than throw these bags away, the manufacturers will sell them at a reduced cost. A comprehensive list of bag manufacturers can be found in the Thomas Register at your local library.
The material we filled our bags with was "reject sand," obtainable from any gravel yard. Reject sand is the by-product of the process that separates sand and "clay fines" from the gravel being produced at these facilities.
This reject material often has the best ratio of clay to sand for rammed earth construction. And..it is dirt cheap! We paid $1.00 per ton but some places will give it away for free.