A Closer Look at Tiny Cob House Construction

Cob is earth, sand, and straw. It’s similar to building with adobe but instead of making blocks to stack-up like with an adobe house, cob houses are built-up while the mud is wet. The material is essentially the same, the construction process is what differentiates cob from adobe.

The most obvious design difference is that adobe homes look more square and cob homes look more organic and sculptural. This is due directly from building with mud when it’s dry (adobe) versus wet (cob). Theoretically you can achieve a similar aesthetic with both methods but cob’s natural tendency is to look much more organic and free.

Brian Liloia is building a tiny cob house at the Dancing Rabbit Ecovillage in Missouri. Last summer he finished the walls and roof. His house has several very interesting design features like a reciprocal roof, a rocket stove, and earthen floor.

The reciprocal roof is a self supporting round roof that’s often made from thin logs that are then fastened together and covered with a more weather proof roofing material. Cob and adobe homes need a good roof to keep the water off their earthen walls.

The rocket stove is a built-in earthen stove with a long flu that snakes through the cob walls and built-in benches. Adobe and cob provide a great deal of thermal mass so that once you heat it up, or cool it down, the temperature of the room is maintained by the mass of the building. The rocket stove in Brian’s home should keep it very warm through the cold Missouri winters and cool in summer so long as he doesn’t light too many fires.

Sealed earthen floors can be very comfortable to walk on and surprisingly clean. They require careful cleaning and will eventually need resealing but they are a far cry from what you might imagine a dirt floor to be like to live with. Linseed oil is often used as a sealer.

Below are some photos from Brian’s blog. He’s documented his design choices and progress in great detail with photos. Visit Brian’s blog to learn how to build a cob house. For more about building with cob visit I Love Cob. There are also many good books on building with cob if you’re serious about building a cob house in the future. One good book on the topic is Building With Cob: A Step-by-step Guide. Photo credit Brian Liloia and friends.

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Cob Building Work Exchange Opportunity for Spring 2009

This is Brian, a.k.a. Ziggy. He currently lives at the Dancing Rabbit Ecovillage in northeastern Missouri. He also writes for Green Optins and recently published an article on my passion for pallets. Thanks Ziggy!

This spring he’ll be finishing up a cob tiny house he started last year. He’s looking for one or two people to come work, live, and learn to work with cob. As a temporary resident at Dancing Rabbit you’ll also get the first hand experience of ecovillage life. Sounds like an amazing opportunity. If you want to learn more visit Ziggy’s blog for all the details about building a cob house.

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Gary’s Hobbit House

My wife Julia loves cob houses and sometimes spots a good story while surfing for ideas for her dream house. Last night she ran across this article in Natural Home Magazine about a guy named Gary in Texas who built his little dream house from mostly reclaimed and recycled materials.

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Gary had no building skills when he started and it took him three years to complete but in the end he ended up with an amazing little house. I think most of us would assume it cost him a small fortune to build, but in the end the total cost including appliances was about $40,000. If that still sounds expensive the 900 square foot structure cost $2,520 in materials: 250 bales of straw ($375), 6 cubic yards of blue clay ($25), 60 tons of limestone boulders ($120), and 50 planed pine timbers ($2000). The article was published in the March/April 2000 issue but who knows with inflation+deflation how much more or less it would cost today.

While this house isn’t exacly tiny at 900 square feet it embodies many of the same values tiny house enthusiasts embrace, low cost, renewable, and simple. I’m sure a tiny cob house could be built with less effort using the exact same techniques. It would be easier to clean, heat and cool too. At the very least this is a very inspiring little house.

If you want to know more go to the source, Gary Zuker’s webpage on his projects. It’s a very simple little webpage (very old school, love it Gary!) with links to the raw files and pdfs of articles on his house. Photo credit Natural Home Magazine & Gary.