SuperAdobe is a form of earth bag architecture developed by architect and CalEarth founder Nader Khalili. Using long sandbags ("SuperAdobe Bags"), barbed wire, on-site earth and a few tools, Khalili devised a revolutionary building system that integrates traditional earth architecture with contemporary global safety requirements, and passes severe earthquake code tests in California.
This technology has been published by NASA, endorsed by the United Nations, featured in countless world media outlets, and awarded the prestigious Aga Khan Award for Architecture in 2004. It comes from years of meditation, hands-on research and development. Inspired by traditional earth architecture in the deserts of Iran and adapted for modern usage. Simplified so that anyone can build.
How It Works
Long or short sandbags are filled with moistened earth and arranged in layers or long coils. Strands of barbed wire are placed between each layer of sandbag to act as both mortar and reinforcement. Stabilizers such as cement, lime, or asphalt emulsion may be added. Similar to how a potter stacks coils of clay to make a vessel, builders stack coils of earth for make a structure.
The SuperAdobe building system can be used for structural arches, domes and vaults, or conventional rectilinear shapes. The same method can build silos, landscaping elements, or infrastructure like dams, cisterns, roads, bridges, and for stabilizing shorelines and watercourses.
Basic Materials Needed:
- Synthetic, low UV (ultra-violet) resistant degradable sand bags
- Four-point, two strand, galvanized barbed wire
- Soil & Water
The building process is intentionally simple, but the structural integrity of SuperAdobe is the result of years of research. The structural design uses modern engineering concepts like base-isolation and post-tensioning. The long coils of sandbag provide compression (vertical) strength. While the barbed wire adds tensile (horizontal) strength. In addition, the sandbags add flood resistance. The earth itself provides insulation and fire-proofing.
Anyone Can Build
Cal-Earth believes that the whole family should be able to build together, men and women, from grandma to the youngest child. We have spent many years researching how to make the process simpler and easier. There should be no heavy lifting or backaches, no expensive equipment, and a flexible and fast construction. The bags are filled in place on the wall using small pots like coffee cans, or even kitchen utensils. You can build alone or as a group.
Why A Dome?
The arch is the strongest form in architecture and has been used in building for thousands of years. A dome is simply an arch rotated 180 degrees. SuperAdobe is extremely well-suited for building arches, domes and vaults, and SuperAdobe domes are extremely strong structures. They have passed California earthquake code tests, and withstood a 7.6 magnitude earthquake in Nepal.
Using geometry and a simple compass tool, builders can easily create corbelled dome structures of various heights and up to 22 feet in diameter.
Plaster & Finishing
All SuperAdobe structures can last several years but to make a structure permanent, the builder must plaster over the sandbag structure. This protects from erosion due to water and weather. Plastering also provides an aesthetically pleasing finish that can be painted or left its natural color.
Once the corbelled dome is complete, it can be covered in several different kinds of exterior treatments, usually plaster. Khalili developed a system that used 85% earth and 15% cement plaster and which is then covered by “reptile”, a veneer of grapefruit sized balls of cement and earth. Reptile is easy to install and because the balls create easy paths for stress, it doesn't crack with time. There are many different possibilities. Some Superadobe buildings have even been covered by living grass, a kind of green roof but covering the entire structure. Any exterior treatment and building details would need to be adapted to a region’s specific climatic needs.