Secondary structural members play a complex role that extends beyond supporting roof and wall covering and carrying exterior load to main frames. There are two main components of secondary structure.
Purlins and girts are cold formed or hot rolled steel sections. These are generally light weight members and can be of different shapes as “C”, “Z”. Purlins are used on the roofs while girts are used on the walls. Purlins and girts both do have uneven legs for lapping.
These are generally cold formed C section and are rolled out to match the roof. Its objective is to support the gutters and act as a junction between wall cladding and roof. Various options are available for eaves strut viz. single slope up, single slope down, double slope up, double slope down. These are used at the joint of roof and sidewall.