As a building material, adobe has been around since man first sought shelter.

“It all began when people combined sticks and mud because that was readily available,” says Kirk Higbee, a Phoenix-based educator and proponent of earthen construction. “Men first lived in caves because they had roofs and doorways. To stop the wind and cold from coming in they put rocks together and used mud to hold them in place. Straw came into the equation as a binder more than 8,000 years ago.”

Warm in the winter and cool in the summer, adobe can be a smart, energy-efficient choice for desert homes because of its relatively high thermal conductivity. “Heat is kind of lazy,” says Higbee. “An exterior wall heats when the sun hits it. That energy moves slowly through the wall toward the cooler interior.” When the sun sets and temperatures drop, the process is reversed. Standard adobe bricks are 16 inches thick, but Higbee notes that to combat the extreme summer temperatures in the Valley, walls can be as deep as 19 inches. Double-wall construction with space between is an additional temperature regulator. “Traveling inward, the heat will hit that dead space and can’t go any further,” he explains.

Since prehistoric times, the recipe for adobe has remained basically the same. Today, bricks made in the U.S. come in two commonly used types—asphalt-stabilized and Portland cement-stabilized.

Asphalt-stabilized is a block that architect and Phoenix Home & Garden Masters of the Southwest award winner Clint Miller has used for more than 20 years in Valley homes. It performs well in our triple-digit climate and possesses the rich russet color that attracts so many enthusiasts. Lighter in color, Portland cement-stabilized adobe has become the common choice in the Tucson area. It is available in many modular sizes, which eases the construction process, and has less erosion on the face of the block from wind and rain.

Miller projects that the adobe homes built today can survive for as long as 800 years provided foundations and roofs are properly maintained, far outlasting wood-frame buildings. But his appreciation of the material goes beyond the practical. “Yes, mass buildings store and release heat better than an insulated wood-frame house, but the reason I love them isn’t about that,” he says. “Adobe looks natural and happy to be in its setting. It blends with the desert. In the landscape that we live in, this material feels at home.”

Higbee observes that there is something about a made-of-mud building that speaks to people on an innate level. “When you walk into an adobe house, you want to feel it,” he says. “The interiors are inviting, cool and calming. Whenever I take a group of people into one of these structures, without fail their first instinct is to touch the walls, which I have never seen happen in a stud-frame house.”

Miller cites cost as a possible deterrent for some homeowners who might consider adobe, noting that a mass earth structure can run as much as 20 percent more than its wood-frame counterpart. But Higbee posits that any differential can be a boon. “From an economic standpoint, where does that additional 20 percent go? Not for transportation or for subsidies on lumber. It’s going back into the local economy.

The way I look at it, I’m paying my neighbor—the contractor down the block, the brick manufacturer, the local businessman—for a building that I can live in that’s more efficient.”

For those who long for the aesthetic without the cost of building an entirely adobe house, Miller says an alternative is to use the earthen blocks as the central spline of a structure with rooms embracing it. “While this doesn’t give you the same energy benefits, it’s a more creative solution.”

What does the tomorrow bring for a material that has been around for almost as long as humans have?

“The state of the art for adobe was achieved some time ago. I’m very skeptical about anyone who comes along and says they’re going to make sweeping changes,” says Quentin Wilson, president of the board of directors of Adobe in Action, a New Mexico-based organization that promotes mass-building home building and ownership through education and student-based field support. “When people are talking about green or sustainable or low carbon footprint, adobe is at the top of the list. I’d love to see everybody on the planet in an adobe house.”

Higbee, who is also an Adobe in Action board member, is excited about what’s ahead. “In Italy and Spain, 3-D printing of adobe structures is being done,” he says. “There’s been research on using it as a building material on Mars because it’s already there.” Closer to home, he hopes to see entire adobe subdivisions. “Why not?” he muses. “Why shouldn’t new homes be built of the soil that they sit on? In the 1950s, neighborhoods of adobe

homes were built in Glendale, and many of those natural-earth structures are still standing.”

Miller is optimistic. “The architectural community feels very strongly about sustainable block and materials that are very green and renewable. Using less forested lumber and more foam and cement composites,” he says. “We think that is the future.

“The success of the adobe industry is very important to the Valley,” Miller continues. “I cannot think of a better building companion for our natural desert. In my mind, it is important for our local manufactures of both asphalt- and cement-stabilized block to prosper, as well as the companion masons who assemble the structures.”

Wilson stresses that what is needed is a new generation of architects, builders and consumers who are passionate about this material. “We need to build awareness about adobe’s incredible versatility. It can be made, literally, anywhere on earth.” he says. “You can’t fool millions of people over millennia. If it was a bad material, people wouldn’t have been living in it across the globe and across time.”