Native American Pueblo Indians understood the value of adobe homes; they built these still-standing structures into the sides of cliffs and on mesas in the Southwest centuries ago. As a building material, adobe has been in use for over 4,000 years. As an insulating material, adobe makes thick walls that keep a home's interior cool during the summer, but, with the addition of a small fireplace, warm in the winter months. Considered a green building material, adobe generally consists of dirt, clay and sand, and it's sometimes augmented by a bit of cement or asphalt emulsion to keep the building intact during inclement weather.
Adobe consists of a mixture of soil, clay, sand and water -- sometimes straw is added -- poured into a mold or hydraulically pressed into uniform bricks and air-dried. The bricks must contain from 25 to 45 percent clay, based on local building codes, to bind the ingredients together when combined with sand and water. In climates with inclement weather, it helps to add a stabilizer to keep the adobe from disintegrating. While making the bricks, periodic crush tests ensure the uniformity of brick strength. Other brick tests include erosion and water-absorption tests.
Passive Energy Homes
When combined with a passive solar design, adobe homes offer an effective energy-saving solution year-round. Its high-mass earthen walls, in conjunction with proper alignment to take advantage of a southern exposure can significantly reduce energy use year-round. While you may have heating and air-conditioning units installed, you won't need to run them as long or as often when the home is built with adobe. A small fireplace can replace the need for a formal furnace, or you can opt for a thermal heat pump instead.
Foundation and Construction
Adobe homes are typically built on a concrete slab foundation with concrete footings buried in the soil to support the walls. The footing depth varies based on the wall's height, width and total weight and local building codes. To protect the walls against crumbling during an earthquake, the bricks are made with holes in the center to allow for rebar reinforcement. Building codes may require a wood or concrete ring beam -- also known as a continuous seismic band, collar or crown -- to ensure adobe load-bearing walls stand up to the force of earthquakes.
Some of the traditional designs for adobe homes include flat roofs with round beams to support the roof sticking out of the walls exterior to the home. But some homes often include conventional roofs; it all depends on the design and the blueprints. A roof with substantial overhanging eaves provides better protection for the exterior walls. While you can may want to leave the look of the bricks on the outside, some homeowners prefer to plaster over the exterior with an adobe mixture to smooth the walls. Cement is not a good choice for an exterior plaster, because it inhibits the ability of the adobe to breathe and may trap moisture that can degrade the bricks.
The interior design theme used inside an adobe home depends on the overall style of the home. Traditional Pueblo-type designs work best with Southwestern themes, multi-hued Native American rugs, round Kiva-like fireplaces, smooth walls or terrazzo tiles for flooring. Most of these traditional designs include neutral color palettes for the walls to serve as a backdrop for the festive and colorful decor and artwork. Outside the home, adobe walls surround a courtyard entry filled with drought-tolerant plants, an outside fire ring and patio, cacti and even rocks.