Building a Cob House
In a time in which we are increasingly hearing scary statistics about the fate of our planet, the way forward in the field of sustainable, green building may just be to go backward. This is certainly the case for people demonstrating a growing interest in building earthen homes and structures using an ancient method known as cobwork or cobbing. Cobbing, believed to have originated in the Maghreb as early as the 11th century, spread into wide usage across many parts of the rest of Europe as the main building style for homes. The name of this style of building comes from the word cob, which is the name of the building material itself, formed of a mixture of earth (such as clay, sand, and other soil), straw, and water. Despite what the materials may imply, this substance, when dried, is fireproof. It is also inexpensive, and naturally cool in the summer heat and relatively easy to heat in the winter.
Many homes built of this material centuries ago still stand and remain in use. Pictured here to the left is a cob house in England, believed to have been built in the late 1700s. (Photo by Tim Green, http://www.flickr.com/photos/atoach/4927564858/) These homes typically have thatched roofs, while small but efficient fireplaces with chimneys provide warmth when the weather is cold.
The appearance and texture of cob varies from region to region, depending on the available natural resources and their characteristics. As such, cob is one of the most versatile building materials on earth. It can be molded and shaped into whatever form is framed by the builder.
This photo on the right is of a cobwork home in the Pacific Northwest of the United States illustrates the potential for great architectural diversity when designing cob homes. (Photo by Gerry Thomasen, http://www.flickr.com/photos/gerrythomasen/1539506253/)What would be impossible for building with bricks and concrete blocks – specifically, achieving low cost, rounded shapes and archways and even rounded windows and doors – is entirely doable with cob. Notice the plants sprouting from the rooftop. Many cob house dwellers prefer earthen roofs with natural, living plant material forming a natural insulation for the structure.
A recent resurgence of interest in cob building has led to several emerging Web communities that provide support and information for each other, as well as interested newcomers. A quick Google search will turn up several how-to guides for building with cob, and some considerations builders may have to address , including building codes in locations across the United States . Because cob building is so easy, even people who have never built anything before can catch on after attending a short workshop series, or single, day-long event. One of the popular, first cob projects is to build one’s own cob oven. The oven is often the starting point, even for a house, though it is equally popular as an end-product, used as a decorative outdoor cooking area.
Cob home building among the most sustainable on the planet, not only because of the materials it is made of, but also the fact that the house will eventually return to the earth whence it came, naturally, at the end of its life (which is, conveniently, not until people utterly abandon it, since cob houses can be easily repaired, modified, and added onto over hundreds of years.)
Cob is also energy efficient, owing to walls that are often a full meter thick. Building with cob allows more customization than other forms of building, and are capable of more truly reflecting the tastes and aesthetic inclinations of their dwellers.
Melonie writes about sustainable living, technology, and travel. She writes for www.directsattv.com. This post has been syndicated by Nathan Brown, the recruiter for Dancing Rabbit Ecovillage’s environmental engineering internships and provider of solar panel building videos.