By Shane Healey
One of the world’s most popular and earliest building method and material is using cob; however, nobody knows where it originated from. There has been evidence that people living the region of Jericho, 10,000 years ago, made buildings made of adobe and earth materials. Along with this area, cob has had major popularity in England, Wales, New Zealand, and Australia. In addition, in 2008, it was estimated that half of the world’s population, three billion people, on six continents live or work in buildings made of natural earth materials. The reason for its popularity around the world is because cob is fireproof, seismic resistant, cost effective, creates tremendous compressive strength, creates no waste, and required little upkeep. The reason cob is so durable, is the materials it is made from. Cob is a building’s material consists of clay (acting as glue), sand (giving strength to the structure), earth, water, and straw (giving its tensile strength), similar to adobe. After research, I found out that Stephen Hren built a 900 square foot cob house that included solar panels, a driveway, a cistern, a septic tank, the foundation, the roof, and all the material to build. This house, with all the items above, cost Hren $19, 500 and took him one year to construct the house. The reason that a small cob building takes a year to build is that no more than one foot should be constructed every two to three days to allow them to dry before adding another layer. In addition, it has been averaged that one person can build a cob wall 25 feet long, 12 inches thick and 4 inches tall in one day, so the more people involved the less time it would take to construct. However, a cob house is only cost effective if you do the work yourself. If you were to hire someone to build it for you, it would cost as much as a traditional stick built house.