Mudbrick

A mudbrick (or mud-brick), also called an unfired brick, is an air-dried brick composed of a mixture of mud (containing loam, clay, sand, and water) with a binding material, such as rice husks or straw. Mudbricks are known to have been used since 9000 BCE. From around 5000–4000 BCE, mudbricks evolved into fired bricks to increase strength and durability. Nevertheless, in some warm regions with very little timber available to fuel a kiln, mudbricks continued to be in use.