Mud bricks are an ancient technology used all over the world, mostly in dry climates, and still in use today.
A brick is a rectangular building block, about the right size for a person to hold easily in their hand. Usually bricks are held together with mortar. Mortar is a substance which at first is soft, wet and sticky; it is laid between the bricks and as it dries it becomes hard.
Adobe bricks are made from a mixture of soil, clay and water. If the local soil contains a lot of clay then soil alone can be used, otherwise clay must be added. Sometimes other locally available materials such as sand, straw or animal dung are added. These materials are mixed together and packed into a rectangular mold, which gives the brick its rectangular shape. The bricks are then laid out in the sun to dry. Drying can take 2 or 3 weeks.
The mortar is usually made from very similar materials to the bricks themselves: water, clay and soil. The bricks are laid in rows with an even layer of mortar pasted in between them. The rows of bricks (or 'courses') are offset so the joins between the bricks don't line up.
Mud brick buildings often do not look like they are made of bricks at all, because the walls are coated with plaster. The plaster adds insulation, helping to keep the building cool in summer and warm in winter, protects the bricks from being worn down by wind and rain, and gives a smooth appearance. The plaster coating is re-applied once a year. Sometimes, the plaster is made from the same materials the bricks and mortal were made from: water, mud and clay. In some other cases, lime plaster is used instead; in this case the building will have a brilliant white color.
Only the walls are made from mud bricks. The door frame may be made from wood or stone, and the door itself is often wood. The ceiling may be made from wood, woven reeds or thin tree branches coated with plaster, or some other material.