As the discussion about health, “green” living and “green” housing moves forward, we are discovering that many of the best solutions are actually very old, low-tech ideas. For years, infant formula had been promoted as a “modern” solution; today we know that breast milk is better. After decades of trans-fats, we learn that natural fats are healthier. Electric and gas clothes dryers replaced the clothesline; now we realize that using the wind and sun to dry clothes leaves a smaller carbon footprint. After widespread use of fiberglass insulation in homes, we realize that insulation made from recycled newspaper is not only “green,” it is even more resistant to fire.
As the world’s great forests dwindle, we become concerned about depleting lumber supplies and rising construction costs. Yet the solution is right under our feet. It is eco-friendly and non-toxic. It is as old as dirt. It’s dirt cheap. In fact, it is dirt! What’s more, it’s the oldest and most commonly used building material in the world! Jericho was built out of it. Parts of the great pyramids of Egypt were built out of it.
More specifically, the dirt-wall solution is called “cob.” Cob is a mixture of earth, straw, sand, and water. It’s been around for thousands of years, and is used in New Zealand, Africa, Central America, Europe, Asia, and just about everywhere. Have you seen the photos of those charming little cottages that dot the landscape of Ireland? Most of those are made of cob. They are coated with a white lime mixture to prevent wind erosion. Just scratch the surface of one of those homes and you will soon discover that the walls are really made of dirt. Surprisingly, many have been around for over 500 years, and are still in excellent condition. These homes are fire-resistant, and stand up quite well to damp environments. If the homes have wide roof-eaves and impervious foundations, wet weather is not an issue. Cob proponents claim that they are warm, dry, and durable.
The production method for cob is about as “green” and as low-tech as you can get. The large amount of heat energy required to produce most brick materials is not needed to make cob. Not much energy is required for transporting materials. Frequently, the right kind of earth is found in sufficient amounts right at the construction site. No power machinery is used. All you need is about a dozen of your friends and family. Earth, sand, water and straw are mixed together with bare hands and feet! When the material reaches the right consistency, it is scooped up into balls called “cobs.” Cobs are stacked and packed into walls and shapes like domes, window benches, curved walls, nooks, window openings, or just about anything that the imagination can conjure up. No internal form structures are required, so there are no limits. Wiring and pipes are set into the walls as they are formed. With no hammers or loud power tools, the participants frequently report a peaceful, almost “spiritual” experience. After about a week of partying in mud with friends and family, your cob house is complete. The home may even look like something that your ancient ancestors lived in.
Will cob homes ever dominate the home construction industry in the United States? That notion seems far-fetched. Will the American consumer embrace cob? Cob homes face re-sale issues, appraisal issues, and financing issues. Building code issues with municipal inspectors will arise. Construction-related industries would probably fight it. Interestingly, third world countries don’t have any of these issues with cob. However, as construction costs rise, and the forests disappear, minds and policies may change.
Kermit Johnson is a full service Minneapolis real estate agent with 14 years of experience. Visit http://www.realestatetwincities.net/blog for blog posts about Minneapolis real estate, Twin Cities homes, Minnesota lake shore issues, green home construction, and other Minnesota realty issues.