Cob Building Basics: DIY House of Earth and Straw| Waccabuc NY Real Estate

In early 1999, a young woman from Florida happened across an article online  about the recent revival of an ancient British method for sculpting dirt houses.  Intrigued, she used her savings to travel to Vermont for a five-day workshop,  where she learned how to mix clay, sand and straw by foot, and then knead lumps  of the stuff into solid walls nearly as durable as concrete.

After returning to Florida, she and some friends used the techniques she had  learned to build a small pottery shed in her parents’ backyard. Some people  predicted Florida’s humid air and torrential rains would melt her “mud hut” back  into the ground. Following Hurricane Lili in 2002, however, the sturdy little  building, which had cost just a few hundred dollars and a summer’s labor to  build, proved to be one of the few buildings left standing in her neighborhood.  Christina Ott had discovered cob building.

Cob-Building Origins

Cob building gets its name from the Old English term for “lump,” which refers  to the lumps of clay-rich soil that were mixed with straw and then stomped into  place to create monolithic earthen walls. Before coal and oil made  transportation cheap, houses were built from whatever materials were close at  hand. In places where timber was scarce, the building material most available  was often the soil underfoot.

Building with earth has a long and successful history. Cob construction is  particularly easy to learn, requires no fancy equipment, uses local materials,  and can be done in small batches as time allows — making it extremely accessible  to a wide range of people. (See DIY Cob-Building Technique, later in  this article.) After her initial success with cob, Ott traveled to Oregon to  apprentice with the Cob Cottage Company. When her family relocated to the  mountains east of Nashville, Tenn., Ott used her new skills to build a small cob  house for just under $8,000. By age 23, she was mortgage-free and teaching  cob-building workshops all over the United States as the “Barefoot Builder.”

In the U.K., tens of thousands of cob buildings are still lived in, some of  them more than 500 years old. When the British immigrated to the United States,  Australia and New Zealand in the 1700s and 1800s, they brought the technique  with them. In Africa, the Arabian Peninsula, parts of Asia and what is now the  southwestern United States, cob was developed independently by indigenous  people. In Yemen, cob buildings stand that are nine stories tall and more than  700 years old.

However, with the industrial age came factories and cheap transportation in  the West, making brick, milled wood, cement and steel readily available. Mass  production led to mass marketing and the promotion of these new materials as  signs of progress. The perception of cob as “poor people’s housing” led to its  near demise. By 1985, there hadn’t been a new cob building constructed in the  U.K. for more than 60 years, or in the United States for at least 120 years.

Modern Cob Buildings

Today, building your own house is the exception to the norm, and it is almost  unheard of to build with local materials. Instead, houses are built by  specialists using expensive tools and expensive, highly refined materials  extracted and transported long distances, often at great ecological cost.  Industrial materials have many benefits — performance, predictability, speed and  ease of installation — but they have in common that they must create a profit  for the companies that manufacture them. The average number of members in U.S.  households has dropped by more than half in the past 50 years. Yet, over the  same time period, average home sizes have more than doubled. We are more  comfortably housed than at any point in history, but practically enslaved by the  payments (the word “mortgage” is French for “death contract”). Fortunately, we  have other choices.

In the county where Ott lives, low-income housing is often a crumbling  trailer home that is difficult to heat and cool and expensive to maintain. As  she sits next to the woodstove in her cozy cob house, she explains that a quick  fire in the morning warms the cob walls and will often keep the house warm for a  day or more. She uses less than a cord of wood per year. Meanwhile, the same  neighbors who laughed about her “dirt house” are stripping their own land of  trees and burning trash just to keep from freezing. Some go through as many as  15 cords of wood per year. For less than what many people spend on a down  payment, Ott has a house, and it performs well even by modern standards.

Cob’s thermal performance varies by climate region. While cob is a relatively  poor insulator, it also has the ability to absorb large quantities of heat.  These properties are valuable in regions such as the Southwest, but would be a  disadvantage in the chilly Northeast, for example, where heat gains will quickly  be lost. This weakness of cob can be solved by building interior walls of cob  for mass heat storage while using better-insulating materials for exterior  walls.

Anecdotal evidence and recent testing show cob walls are highly resistant to  earthquakes. Unlike cement or adobe, which tend to shake apart in an earthquake,  lumps of cob are woven together in the building process to form one large mass  reinforced by straw fiber. Also, unlike cement, cob is easily repaired with the  same material it was built from, and if torn down, there is no waste to be  disposed of — only earth that can be returned to the ground or soaked in water  and reused to build another room or house.

Oregon Cob-Building Method

Outside Coquille, Ore., stands a constantly evolving collection of test  buildings affectionately known as “Cobville.” Sculpted cob garden walls weave  around and between the tiny cottages, giving each its own sense of space. Here,  apprentices and workshop attendees learn and experiment with ingredients,  methods and finishes. This is the headquarters of the Cob Cottage Company, which  is largely responsible for the re-emergence of cob building in the United  States. Founded by Ianto Evans, his wife, Linda Smiley, and Michael G. Smith,  Cob Cottage Company started with the radical idea that, with a little direction,  almost anyone can learn how to build a cob house.

Evans, a spry Welshman now in his 70s, has reimagined the cob of his  birthplace in a more efficient form. The traditional British cob method, which  was generally to stomp lumps of whatever clay soil was handy into place, relied  on thick walls for strength. “Oregon cob,” by contrast, effectively does more  with less. Builders make thinner but significantly stronger walls by tightly  controlling the clay-and-sand mix and using lots of straw for reinforcement. “We  have created in Oregon cob an almost-free building material most people can  manufacture for themselves. It has fluidity of form, and it’s healthy,  non-polluting and local. The buildings it inspires are sculptural, snug and  permanent,” Evans says. Because you can provide much of the construction labor  yourself, cob is very affordable.

But Evans speaks of cob and “natural building” (a term he helped popularize)  less in terms of cob-construction methods and more in terms of the social  movement it has become. “Building your own house for less than $10,000 is  revolutionary, and, yes, you can do it,” he says. “Millions of people in other  countries and our own ancestors have proven that.” Evans has seen firsthand the  way people are empowered by building their own houses from earth.

Cob-Building Community

Thirty years after its founding, Cob Cottage Company has much progress to  report. Evans, Smiley and Smith’s book, The Hand-Sculpted House, has sold more than 30,000 copies  worldwide. Their CobWeb newsletter documents 18 years of experiments  and advances (and failures) in cob technology, and it is available at the Cob Cottage  Company. Multiple nonprofits, such as the Natural Building Network,  continue to promote cob building and work with code officials to streamline the  approval process. Every year, natural builders host regional colloquia to swap  techniques and foster camaraderie. Some travel hundreds of miles and sleep in  tents to help each other with projects.

Cob Cottage Company alumni are building and teaching all over the world.  Despite the downturn in the global economy — or maybe because of it — cob  workshops are more popular than ever. On her first building project, Ott’s most  steadfast supporter was an unemployed single mother who went on to build her own  cob house after her first home was destroyed by a hurricane. Together, they  built a building while chatting and watching kids run around the yard. A  construction site is not a playground, but without the noise and danger of heavy  machinery and without nails littering the ground, a cob-building site is a great  deal more family-friendly. Most natural builders go to great lengths to keep  that atmosphere on their job sites. Many times I’ve been grateful for that as I  watched my young daughters hard at work atop the growing cob wall of a friend’s  new bedroom.

If you are serious about building with cob, Evans strongly recommends that  you seek hands-on experience, either at a workshop or by volunteering on a  project. To find a workshop near you, visit the event calendars on the websites  listed in the resources box to the left.

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