Cob comprises of a stiff mixture of clay sand, water and straw, which is freshly packed onto a stone or masonry base wall to create sturdy load bearing structures. Traditionally buildings of this kind are known to last many hundreds of years. The clay acts as a binder, the sand gives strength, while the straw acts as reinforcing. With straw bale construction, cob makes an excellent medium for plugging in odd gaps. It can also be used to create solid sculptured reveals around openings and niches.
Cob has got nothing to do with meallie or corn cobs as sometimes mistakenly thought!!