The word adobe comes from the arabic word atob whichmeans muck or sticky glob, or atubah " the brick". The word adobe is widely used throughout the United States and Spanish speaking countries. It can mean adobe block, the mud used to produce them, or the architectural style.
WHAT ARE ADOBE BRICKS?
Adobe bricks are soil and water mixed together (mud) , placed into a mold, and then baked in the sun. The resulting bricks can be any size and shape, but as they get bigger, they also get heavier. The most common size available in the Albuquerque area is 4 inches thick, by 10 inches by 14 inches.
Depending on how you lay them in the wall you can have a 10 inch thick wall, or a 14 inch thick wall, or you can combine them to build a 24 inch thick wall.
HOW ARE ADOBE BRICKS MADE?
In the past adobe bricks were made by hand, with no means of mechanical support. The forms were made of wood and allowed around 4 adobe bricks to be made at a time. The soil, with as high a clay content as the adobero could use was mixed with only enough water to allow the mix to be pounded into the form. The form was immediately removed allowing the bricks to dry in the sun for a few days before turning them on edge to futher aid in the drying process. The form was cleaned, and the process was repeated again and again until enough adobes were made to build what was needed. If the soil had to high a clay content, straw was added to help reduce the shrinkage cracks as the adobe dried.
Now, because front end loaders and mechanical lay down machines have replaced the hands on method of the past, new rules have changed the way adobes are made. Because the mix needs to be much wetter, more aggrigate needs to be added to prevent shrinkage cracks which means the adobe has lost some of it's water resistance. This is overcome with the addition of asphalt emulsion. Depending on the percentage added to the mix, the adobe will be either semi, or fully stabilized. Semi meaning the adobe will last through and beyond the construction of the home before being covered against the elements. And fully stabilized meaning it will last indefinitely, without extra protection.
IS ADOBE A GOOD INSULATOR?
The actual insulating value of adobe is poor. But, unlike fiberglass insulated walls, adobe walls have the ability to store heat. The thermal mass of the adobe wall helps the structure stay
within an average of the high and low temperatures found outside several days earlier. As the outside temperatures change up to 40 degrees in a 24 hour period, the indoor temperature will vary only a few degrees. We also add 2 inches of rigid insulation to the exterior of the home which further adds to the R value of the wall. Also, the adobe wall is solid, where the frame stucco wall has voids in the insulation at every stud which means the installed and in place
R value of an R-19 fiberglass wall is considerably lower.
IS ADOBE EXPENSIVE ?
Because an adobe home is almost always a custom home, and I mean custom, not just a plan that might work "again", the answer is yes. But it is not the adobe that makes it expensive, it is the look, the detail, and the quality that runs up the cost. A traditional adobe home, like the one being featured on this site has either beams and decking, vigas and latillas, or other special ceiling treatments in every room, closet, and hallway. The only ceiling covered in drywall is in the garage. Every floor is brick, every wall is hand plastered, every door is hand made. A frame stucco house with the identical finish schedule would cost the same. If you try to duplicate the thickness of the adobe wall in the frame house, the frame house would be substantially more.
IS ADOBE A "GREEN" BUILDING MATERIAL?
Adobe is probably the only true "green" building material available today. Adobe is made out of dirt, and practically any dirt will work. Adobe relies only on the sun for drying. The only other energy associated with the manufacturing process is the gas used to transport the materials. And that can be eliminated entirely, with a little extra effort, by making the adobe on site. All the other building materials, including concrete filled foam forms, manufactured lumber, Rastra, all use enormous amounts of energy in the production and transportation of the finished product. The only material that comes as close to being environmentally friendly as adobe is straw bale construction. But for a person desiring to build a true passive solar home, NOTHING works as well as adobe. Because the walls are not insulated on the inside, as in the foam form walls, the adobe walls are able to absorb the warmth from the sun collected from the south facing windows. Not even straw bales can do that.