To continue the theme of ingenious construction techniques for bioconstructors [natural builders], sacks of earth are a versatile and modern adaptation of a traditional way of building.
Building with earth has unique and beautiful qualities, as it is easy to heat and keep cool and has great soundproofing and a stable and healthy level of humidity. The traditional method of earthen walls was compacted with a wooden formwork is moved when each piece is completed, which is proven and has stood the test of time, but the sacks of earth construction is simpler to start with very little equipment or knowledge. The soil is compacted in polypropylene or burlap bags. It is easy to create forms and arches which eliminates the need for lintels over doors and windows. The vaulted roof may therefore not require precise beams.
Imagine! I almost have the building! The bags can be filled with most types of soil that contains clay. If they do not have to bring natural clay soil rich in clay and mix it with soil from the site and if the clay content is too high you have to add another earth or sand. You can do a simple test to determine the ratio of clay and sand. This construction is cheap, or free, and the bags are easy to find in Spain. The bags are lightweight and easily transported anywhere and the heavy construction materials are already on the site!”
Source: La Chispa