Brick

Bricks are one of the oldest types of building blocks. They are an ideal building material because they are relatively cheap to make, very durable, and require little maintenance. Bricks are usually made of kiln-baked mixtures of clay. In ancient times, bricks were made of mud and dried in the sun; modern bricks are made from concrete, sand and lime, and glass. The physical and chemical characteristics of the raw materials used to make bricks, along with the temperature at which they are baked, determine the color and hardness of the finished product. Bricks are made in standard sizes, are usually twice as long as they are wide and, since most bricklaying is done manually, are made small enough to fit in the hand. Bricklayers use a trowel to cover each brick with mortar—a mixture of cement, sand, and water. The mortar hardens when dry and keeps the bricks in place. Bricks are arranged in various patterns, called bonds, for strength.