 The most ancient structures of the Southwest region of the United States that are still standing are represented in buildings made from adobe used in homes and missions, such as those in Southern California and Santa Fe, New Mexico. The early settlers of the region constructed homes of adobe because the materials were plentiful and at hand. Due to the lack of wood or masonry material, adobe was the choice for early shelters. Today, we have discovered that this material is not only abundant but also adaptable to changing climate and temperatures.
Traditionally, adobe brick measures 10x14x4 inches. Ideally, the mixture contains 20 percent clay and 80 percent sand. These materials are mixed with water and acquire a more fluid state that allows it to be poured into wooden forms with the above dimensions. When the water evaporates, the brick becomes hard while baking in the sun. At that point is then removed from the mold and stacked one upon the other like fallen dominoes. About 30 days later, the bricks become as strong as cement.
The use of straw is commonly considered an essential part of the adobe brick. However, contemporary bricks of adobe do not contain it. The use of straw is thought to impart rigidity to the brick and prevent it from cracking during the curing process. If, however, the proper proportion of sand to clay is used this should not occur.
In terms of energy conservation adobe walls are very thick and have significant thermal mass, which reduces heating and cooling costs as well as provides sound insulation, structural integrity, and fire and pest protection. Like traditional adobe or concrete structures the walls are heated throughout the day, while maintaining a comfortable temperature on the inside. Then the heat is released slowly throughout night also contributing to a comfortable interior. It does not insulate very well, so walls made of adobe need some means of providing insulation to maintain comfort in the building. Sometimes this is accomplished by creating a double wall, with an air space, straw or other eco-friendly insulators or some other insulation in between. Another approach is placing insulating materials on the outside.
Super Adobe is a form of adobe that was developed by Iranian architect Nader Khalili. The technique uses layered long fabric tubes or bags filled with adobe to form a compression structure. The resulting beehive shaped structures employ arches, domes, and vaults to create single and double-curved shells that are strong and aesthetically pleasing. It has received growing interest for the past two decades from the Natural Building and Sustainability movements. Due to Super Adobe’s inexpensive nature, ease in construction, and use of locally available materials, it has also been proposed for use as a long term emergency shelter.
Another vital aspect of having a green or sustainable design is a structure’s connection to its natural environment. Adobe’s major ingredient is earth, which is non-toxic and readily available. If the earth is not from the immediate site than locating a nearby source is generally not terribly difficult. Such close proximity to a materials source decreases the materials embodied energy, another focus of sustainability.
If you are considering the switch to adobe, you are making a good decision. Building sustainably does not just entail a focus on the health of the inhabitants of the structure or the environmental impacts of a certain technique or material. The ethical, social, and economic impact of the technique and materials must also be considered.
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