As people search for affordable, energy efficient solutions to home building and remodeling, a number of local residents have begun employing the ancient technique of cob building – fashioning buildings, decorative walls and other structures out of mud.

Cob buildings are made with sand, clay and water so they are literally “dirt cheap.”

Earthen homes are common in many parts of the world, including the southwestern United States, where the 500-year-old Taos Pueblo near Santa Fe, N.M., and the Native American ruins at Casa Grande in Arizona illustrate how long this method of building has been in use.

One reason construction using the cob building method is becoming more popular is because cob buildings are organic, functional, and long lasting. Cob structures reduce the use of wood, steel and toxic building supplies, and the building methods are flexible and forgiving and allow for sensuous curving lines with decorative flourishes. In moderate climates, the earthen mass helps hold in the sun’s warmth, creating fairly stable temperatures throughout the year.

Cob building is also labor intensive, so it’s best to plan, collect materials and start small. Once a main cob structure is built, it is easy to add on and enlarge the building.

Experts in cob building say determining a site for the structure and orienting it for the desired solar exposure is extremely important. Drainage, if it is an issue, should be carefully planned out and once the preliminary work is done, construction begins easily.

The first step is to dig a trench and lay a foundation of rock. The basic recipe for cob material begins with a mixture that is 50 percent to 80 percent sand, 50 percent to 15 percent clay, and straw and water. Reject sand is inexpensive and works well. Test bricks should be made to check for drying and shrinkage issues.

The cob mix is applied by the handful and tamped it into the already-laid foundation. When cob bulges out the sides of the foundation it’s technically called “ooging.” Roofs can be made of wood, metal or hard plastic sheets and are typically the most expensive material in the structure. Floors can be made of tile, brick clay or rammed earth sealed with a mixture of linseed oil and a solvent such as turpentine, mineral spirits or citrus to help the solvent soak in.

A few years ago, local resident Michelle Stenta built a cob garden shed. She said she had no experience with cob building, but chose the method because “it was cheap, easy and simple.” Her total cost of materials was about $300 with $200 of that covering the cost of the metal roof; the rest paid for the reject sand.

Grand County resident Teri Ann Tibbetts crafted an artsy chicken coop from cob, using junk, items she recycled from the landfill, gifts of materials from friends and construction remnants that she found on her property.

The total cost for Tibbetts coop was about $100 for rigid plastic sheeting for the roof and reject sand.

“I am not a person who thinks inside the box,” Tibbetts said, explaining why she chose to build using cob techniques. “It was so much fun to build that I want to do another structure.”