How Adobe Construction Works

If you've spent any time in the southwestern U.S., you likely know that adobe construction is one of the oldest and most versatile building techniques used by humans. You can find it in the simplest of one-room huts and the world's most elaborate mosques. It's everywhere—but what exactly is it? And where did it come from?

Today, this time-honored material is gaining new popularity as a low-cost, environmentally friendly way of building. There's a growing movement among do-it-yourselfers and community action groups to build with adobe. Adobe construction is not especially complicated. After all, adobe is really nothing more than simple bricks made of sun-dried mud. What's more plentiful or inexpensive than dirt and sunshine? As a green-building bonus, adobe helps keep buildings naturally cool in summer and warm in winter, reducing the need for air conditioning and heat.

Be careful before you start building, though: Adobe works better in some places than others. Since adobe bricks are dried in the sun rather than cured in a fire, they aren't particularly hard. In fact, they shrink and swell with the weather. Here's where things get problematic: An extremely wet climate prone to flooding might turn the bricks back into mud. Not only that, frequent freezing and thawing can make the bricks crumble. This is why adobe is used primarily in dry, mostly warm climates such as the American Southwest, the Mediterranean region, parts of Latin America, the Middle East and arid parts of Africa and India. However, with careful site selection and construction techniques, adobe can be used in wetter and colder areas.

Before we get to building with adobe, though, let's take a look at its history.

Ancient Architecture

Adobe was one of the first materials ancient humans used to create buildings, dating as far back as the eighth century B.C. The word "adobe" is Spanish, but etymologists trace its origins to an old Arabic word, al-tob or al-tub, meaning "brick."

Native Americans, who built the beautiful cliff dwellings you can see today at Mesa Verde National Park in Colorado, built pit houses and other structures of adobe before they began using sandstone.

Adobe construction spread throughout warm, dry climates. It was used in Spain and other Mediterranean areas, and the Spaniards who led the conquest of the Americas found Native Americans already using it. In the United States, many examples of historic adobe architecture can be found in Southern California and the southwestern states. Santa Fe, New Mexico, for example, has many adobe structures, including the Palace of the Governors, which dates to the early 17th century. The Historic Taos Inn, also in New Mexico, includes several adobe houses built in the 1800s; tourists often visit the San Francisco de Assisi Mission Church in Rancho de Taos.

The largest adobe building in the world, and probably the most famous adobe structure standing, is the Great Mosque of Djenné in central Mali, near the edge of the Sahara Desert. The Great Mosque was built in 1907 on the ruins of earlier mosques. It has walls as thick as 24 inches (61 centimeters), and arches measuring 45 feet high (13.7 meters) and covers some 62,500 square feet (5,806 square meters). Djenné was long a center of learning and trade. Wealthy merchants built elaborate houses from the mud that was plentiful along the creeks that led to the Bani River. The town was built on hills to protect it from the river's floods. Many of these houses still stand today.

How are adobe houses made, anyway? Keep reading to find out.

Add Water, Then Stir

Adobe construction today follows many of the same principles used since the ninth century B.C. Some brick-makers use variations: They use artificial heat rather than the sun to dry the bricks, or they pour the adobe mixture into larger molds rather than making individual bricks. Others add cement, asphalt or other substances to make the bricks stronger. But bricks that have been dried by fire or that have additives don't have the same appearance and texture as those made in the traditional way.

Here's how adobe bricks are made:

Sand and clay are mixed with water.
Straw or grass (and sometimes manure) is usually added. This helps the mud shrink into uniform brick shapes as it dries.
The mud mixture is put into wooden forms and leveled by hand. You can make them any size or shape you want, but they should be easy to move by hand.
The bricks are removed from the forms and laid onto a surface in the sun that's covered with straw or grass.
After they have dried for a few days, the bricks are set on their edges for at least four weeks of air-drying.

Here's the basic method for building with adobe bricks:

Build your foundation. Adobe houses usually don't have basements. Foundations can be made of stones or other locally available materials.
Lay the bricks with mortar. Mud works best because it shrinks and swells with the bricks. Cement and similar mortars are too strong and rigid.
Stack bricks together to make thick walls—10 inches (25.4 centimeters) or more—for strength. This mass helps cool the house summer and warm it in winter. Adobe houses are usually rectangular and rarely more than two stories high.
Leave openings for doors and windows. There shouldn't be too many, as they will weaken the structure. Use wooden lintels (supports) over openings.
Choose a roof. Roofs on adobe houses traditionally vary with the location. Many people choose thatched roofs. Often, builders use logs or rough timbers (called vigas) as beams, with sticks laid over and between them under the roofing. Some people use adobe mud as roofing. Today, builders like terra cotta tile, wooden shingles and metal roofing. The roof should be fairly flat but not level since water needs to run off.
Select a coating. Builders use coatings of mud plaster, whitewash, lime plaster and cement stucco to protect adobe walls.

Adobe may have a long history, but it's positively cutting-edge in some circles. Read on to find out more about modern adobe construction.

Brown Is the New Green

There is a growing interest in new adobe construction, especially in the American Southwest. Because adobe bricks are made of dirt and dried by the sun and air, they're an inexpensive eco-friendly building material.

Adobe construction is popular with individuals and organizations interested in low-cost housing that does not harm the environment.

Here are some of adobe's assets:

It's renewable; after all, you can find dirt just about anywhere.
It's local; materials don't have to be hauled in.
It's inexpensive.
It's healthy; adobe doesn't release chemicals, as some modern materials do.
It saves energy; Thick adobe walls have lots of thermal mass. They collect heat from the sun during the day and release it slowly at night. That helps with cooling in summer and heating in winter.
It's so easy that many people learn to do adobe construction themselves. It's also a good strategy for volunteer groups building homes for others.
It's durable; with proper maintenance, an adobe structure can last centuries.
It's fun; if you liked Lego blocks as a kid, you'll enjoy building with adobe bricks.

Keep reading for lots more information about adobe.

Adobe School

If you want to learn more about adobe construction, you're in luck. There are private companies that offer classes. Some companies that sell adobe-making kits and equipment offer also instruction. And if you're really serious, you can go to college to learn more. No, really: Some schools in the United States, like Santa Fe Community College, offer programs in adobe construction. Students learn to use traditional Southwestern techniques to build adobe buildings. You can find more information here.

Author's Note

Having traveled a good bit in the American Southwest, I was aware of the historic adobe buildings there, many of which have stood the test of time. As I researched adobe, I was not surprised to learn how widely this ancient method of construction has been used, but I was awed by the magnificence of some of the structures in Africa and the Mediterranean. The discovery that intrigued me most, however, was to learn that this time-honored method is having quite a revival in parts of the Southwest as a low-cost, earth-friendly, sustainable way for people to build their own homes or for volunteers to help build homes for others. The ancient people knew what they were doing!

Sources

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