What are cob houses? Well, they are not made from corn cobs. They are made out of earth mixed with straw and other earthen ingredients. Sort of like adobe. Sometimes they have hay bales for wall insulation, then the bales are covered with the earthen plaster, and then usually a lime plaster over that so it doesn’t wash away. Cob houses can be as simple or complex as one wants them to be. They can be embellished or left plain, painted crazy colors or left white or natural.