1. Adobe
Adobe is one of the oldest forms of building with earth, with examples all over the American Southwest, the Middle East, South America and Africa. Adobe is made by pouring a mix of clay, sand, water and sometimes straw into a form, most commonly a brick. The forms are left to dry in the sun, and then the forms are removed. This curing process can take some time, and it requires a continuously dry climate so that the bricks can solidify without getting wet. As the bricks dry, they shrink, so they should be inspected for cracking. Adjusting the ratio of clay and straw can help to prevent cracking; because the levels of ingredients vary widely among adobe bricks, it's best to make some test bricks to determine if they'll crack.
Adobe bricks are stacked just like conventional masonry and typically connected with a mud mortar. However, adobe walls are vulnerable to moisture and usually need large roof overhangs and elevated foundations in wet climates. In addition, adobe buildings are not a good idea in earthquake-prone areas, although concrete can be added to bricks to stabilize them.
To learn more about natural building and how to design your own eco-friendly home, visit the links on the next page.
