Purlins Shed Roof

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 shed roof.

This design is a lot stronger and more robust way of making a steel shed. Welded together they can be used as columns braces and ties. Also known as sheeting rails purlins create the roofing members of the secondary framing of a steel building. The purpose of purlins.

They give added support to the roof and also provide a nailing surface for the end panels and drip edge. Purlins are 2 by 4 feet and are installed much like metal roofing. In architecture or structural engineering or building a purlin or purline is a horizontal structural member in a roof. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top.

Purlins and girts are used longitudinally to support the roof sheeting which they were originally designed for. The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed. The shape of cee purlins does not allow end lapping they are butted together. Cee purlins are secondary steel framing members most commonly used as roof purlins wall girts and header jamb and sill for windows and doors on metal buildings.

Spacing is typically 24 on center in low snow loads and is reduced based upon truss span and snow load. Purlins are an important component in a pre engineered steel structural kit.