Adobe:
Adobe is the popular Spanish word for mud brick. The term Adobe refers to an unfired earth brick used for building walls. Adobe bricks are made of sand, clay, water, and sometimes straw.

The brick typically measures approximately 10"wx14"lx4"h. The bricks are dried in the sun and then stacked to build walls. Often covered in stucco or earth plaster, adobe walls provide excellent thermal mass that combines well with passive solar heating. Adobes can also be used to form vaults and domes. Adobe is a forgiving material.

Some feel that the unfired clay in adobes has an additional low- tech evaporative cooling effect similar to a phase change material.

Sometimes adobes are stabilized with various additives to make them more impervious to moisture. Most of the oldest structures still in existence are were constructed with adobes. An adobe is a very natural product. Some estimates suggest over 1/2 the worlds population live in earthen structures.