Bruce and I attended a four-day workshop at Southwest Solar Adobe School in Bosque, New Mexico, where Joe Tibbets taught us how to make adobe bricks and how to build walls. Joe is a master of earth building, both bricks and rammed earth. He’s a true believer and an excellent teacher, and publishes an excellent magazine, Adobe Builder.
We arrived at the adobe building school with a 5-gallon bucket of soil from our hillside from which Joe took a sample, shook it up in a jar of water, and let it settle out. As he carefully studied the layers that formed in the jar, he pronounced our soil a perfect natural mix of clay and sharp sand. The only other ingredient we would need is asphalt emulsion to make “stabilized adobe,” adobe that does not melt in the rain. The liquid asphalt does not add strength, it coats the clay particles so they do not melt.
And we did not use straw. Everyone thinks adobe blocks need straw because that is how Spaniards made adobe in California, but in fact, straw is only necessary when the clay content is too high; the pieces of straw make voids that allow the clay to expand and contract without cracking the brick. If you have the optimum mix of clay, silt, sand, and aggregate (as we did by pure chance!) you do not need straw.
After four days of intensive workshops, we left New Mexico convinced we could build our own adobe home.
Our adobe garage appears on the cover of this issue of Adobe Builder. The shape of the building mimics the shape of Mayan homes in Yucatan.