Structural steel framing, which includes structural stainless steel framing, describes the creation of a steel skeleton made up of vertical columns and horizontal beams. This skeleton provides the support for the roof, floors and walls of the structure. There are three main types of structural steel framing systems. They are the clear-span rigid frame structure, the modular structural frame and single slope frame style. Choosing which type of steel frame to use for a given project requires the consideration of a number of factors, including building width, height, location, roofing type, and building use.