There is the use of large flat roof sloping roof without purlin roof system and with a long foot pressure plate purlin roof systems; roof slope is generally purlin roof system.

On steel roof truss structure in the form of housing, small series that depends on constant Kelly steel housing requirements, chaining roofing materials, roof trusses and columns (articulated or rigid connection), the overall stiffness of the roof and other requirements, according to the roof truss structure can be divided trapezoidal roof trusses, triangular roof trusses, roof trusses and two twisted arch spindle roof trusses and other four kinds of styles of steel roof trusses; according to the material used can be divided into ordinary steel roof, light steel roof (the lever is round and small angle ) and thin-walled steel roof trusses in three forms.