Roof tiles are usually produced from locally accessible materials such as terracotta or slate and are intended to keep rain out. Concrete, metal, and plastic are also utilized today, and some clay tiles have a waterproof coating. They are designed to withstand the weather and wear-and-tear of time without breaking down. Terracotta is the term used to describe pottery created from clay that has been dried in the sun or under heat lamps. The process of making terra-cotta allows for a wide variety of colors and textures to be obtained. It is this ability to create so many different shapes and sizes that makes terra-cotta such an attractive material for roofing. Slate is a hard, blue-black rock found in many parts of the world. When quarried, it is split into large flat pieces called slates. These are then dried in the sun or under heat lamps to remove any moisture contained within them and prevent warping. Slate roofs are very durable and can last for hundreds of years if maintained properly. However, like all other types of roofs, they can leak if not done correctly at the time of installation. Tile is a generic name given to thin, flat stones that are laid next to each other to make a surface of a certain size.