The roof structure is generally a steel truss system which can be designed for metal sheets or tiles. This is a roof truss system which typically consists of C90 and C140 sections as the chord and web members of the truss. The steel roof framing system can suit all types of roof design – hip, gable, dutch dable, steel roof sheeting or tile and would be screwed directly onto the wall frame. When using tiles, wooden-styled roof trusses are used with purlins running across them for the tiles to be fitted.