A rafter is a structural component used in building roofs. It is typically made of wood or metal and is designed to support the roof's weight and distribute loads to the walls of a structure. Rafters are usually arranged in a sloping manner, allowing for effective water drainage and snow shedding. In traditional construction, rafters are often part of a larger system that includes trusses and purlins. They can vary in size and shape depending on the design of the roof and the materials used. Proper installation of rafters is crucial for the overall stability and durability of a building.