What is cob?

The word cob originates in old English as a root word meaning a lump or rounded mass. Cob is a natural building material made from subsoil, water, straw, and sometimes lime. The constituents of subsoil vary, and if it doesn't contain the right mixture, then it can be modified with sand or clay to attain the proper consistency. Building with cob utilizes one's hands and feet to form lumps of earth mixed with sand and straw. Building with cob is easy to learn and inexpensive.

What are the benefits of cob?

Building homes out of cob is an ancient technique which has been used for an estimated 10,000 years. Cob houses have thick walls, meaning they regulate their temperature well. In the hot summer, the walls keep the interior of the house cool. And, in the winter, the inside of the home will remain warm. Cob construction is extremely durable and won't begin to weather for years. If you notice the exterior of the home wearing down, you can re-apply a new layer of cob. Cob is an extremely durable base material, and the whole structure acts as one monolithic piece. They are resistant to earthquakes, to the point that they will not even develop cracks during an earthquake. Cob houses are fairly fire resistant, being built primarily out of clay and sand as opposed to wood. Thus, cob is a good option in areas that are prone to wildfires and other extreme weather. Cob houses are healthy and great for air quality.

How does it look?

Cob homes have a unique style and curve to their walls. They appear like hand-sculpted houses. They're comfortable and appealing. Because there are no forms, ramming, cement, or rectilinear bricks, cob lends itself to organic shapes such as curved walls, arches, and niches.

Is it economical?

Cob is made out of inexpensive materials, and it can be acquired in large quantities. Cob homes are built to last forever, as long as their roofs are maintained and they are properly looked after. It can take months to years for the cob house to dry out fully, so you'll need to pay attention to moisture. Most of the moisture will dry out in the first year, but will not fully cure for another for one to two more years. Once construction is complete, and the roof is added, allow it to breathe for several months before moving in. Then an internal sealing process needs to be done. Then, a dehumidifier will need to be used to reduce the amount of moisture in the air. This process will improve the damp quality of air in the home. With rising prices of lumber and increased interest in natural and environmentally safe building practices, cob is becoming an attractive option.

This ancient technology doesn't contribute to polluting the environment nor depleting natural resources, and it is not dependent upon power tools. As a material, earth is non-toxic and completely recyclable. In the modern times of environmental degredation, dwindling natural resources, and general toxicity, cob is an abundant, cheap, and healthy building material.

 Sources: 

https://www.cobcottage.com/whatis

https://gokcecapital.com/what-is-a-cob-house/