Purlins traditionally support the roof deck cladding sheeting and are in turn supported by the principal rafters steel beams etc.
Roof purlin beam.
In a structural steel shed the main portal frames and roof rafters are made from strong steel sections which are welded together and later bolted together.
Purlins are supported either by rafters or the walls of the building.
Available in a variety of sectional properties lengths and sizes.
Like the z purlin the c purlin takes its name from its shape.
Purlins support the loads from the roof deck or sheathing and are supported by the principal rafters and or the building walls steel beams etc.
This design is a lot stronger and more robust way of making a steel shed.
In homes with full second floors the main level ceilings often use log beams for overhead looks and to support the ceiling which is also the upper level floor.
Purlins and girts are used longitudinally to support the roof sheeting which they were originally designed for.
In the past the majority of roof structures were of wooden construction but over the past 15 to 20 years there has been a vast shift away from wood to metal mainly steel roof construction.