It’s estimated that half of the world’s population lives in earth buildings, but for many countries this type of architecture was until recently fairly rare. Now materials like rammed earth, cob, compressed earth and mud brick are experiencing a comeback.
A modern cob home- Cobtun House- in England won the Royal Institute of British Architects’ sustainability award and went on to sell for well over a million dollars (750,000 pounds). And cob is just a simple mix of clay and straw (though sand or some sort of grit is often used as well).
Cob is cheap- the walls of Cobtun House cost just 20,000 pounds- and infinitely recyclable. It’s also a very green building material for plenty of other reasons.
It’s a local material: the clay and sand are most often extracted from the property where the building is built. It’s energy efficient: cool in the summer, warm in the winter and fire-resistant. It’s efficient with space since cob buildings are smaller than the average American home.
A cob home is also a perfect DIY project since the materials can be mixed with your hands and feet and molded freeform- without support structures- to create a house (See books like The Hand-Sculpted House: A Practical and Philosophical Guide to Building a Cob Cottage).
In this video, Margaret Krome-Lukens of North Carolina’s Pickard’s Mountain Eco-Institute shows us the cob home- refreshingly cool on a hot summer’s day- that interns Mike and Greg are building for her on the property. They talk about the horse manure used as an additive to the walls, how the material is so easy to sculpt, the green roof and living small. Since her new home is less than 150 square feet, Margaret talks about the joy of giving up stuff to move in.