Light-gauge cold-formed steel roof purlins replace heavier hot-rolled steel angle and channel sections. A purlin is a secondary structural member that spans between the primary/main steel frame to support the roof cladding. The purlin transfers load from the roof cladding to the primary steel rafters. Similarly, a side rail is a secondary structural member that spans between the primary/main steel frame to support the wall cladding and transfer load from the wall cladding to the primary steel columns. Both purlins and side rails are used to provide restraint to the primary steel frame members. Light gauge cold-formed steel roof purlins are used on a wide range of building types including retail and leisure, industrial, warehouses and distribution, healthcare and education.