Would you live in a cob house? 🍄🏠 “Cob” refers to the building material, which is essentially a mixture of clay, sand, and straw. These earthen components are mixed with water and can be used to construct natural durable walls. Cob is also sustainable. Its high thermal mass makes these structures energy-efficient. The components are naturally-occurring and widespread resources. This means that builders can almost always source these components locally, making them low-cost to the builder and a