Steel Purlin Roof Design

In timber construction purlins are nailed to the rafter or supporting trusses while in steel roof construction they are welded or bolted to the rafters or trusses by the means of cleats.

Steel purlin roof design.

Roof purlin are members used to directly support roof sheeting materials and could be made of timber or steel. Steel z purlins and z girts are also available with other depths and flange widths. This design is a lot stronger and more robust way of making a steel shed. In structural steel or aluminum construction p urlins usually w shapes or channels transfer roof loads to the major structural elements supporting the roof.

They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. 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. The type and spacing of purlins is a design consideration which depends upon the incident roof loads as well as the limiting lengths of sheeting to be used. They give added support to the roof and also provide a nailing surface for the end panels and drip edge.

Contact flexospan for information on custom purlin and girt structural steel dimensions. 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. We manufacture any component from 1 2 steel subgirts to 12 section up to 10 gauge. Purlins are 2 by 4 feet and are installed much like metal roofing.

The shape of cee purlins does not allow end lapping they are butted together. Welded together they can be used as columns braces and ties. Purlins are installed horizontally under metal roofs. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top.

Steel roof purlins and wall girts are produced and available in house. 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. Purlins are 2 by 4 feet and are installed much like metal roofing. Engineered purlin metal mart offers a complete line of engineered purlin material.

Available in cee or zee shape red oxide primed or galvanized 16 14 or 12 gauge sizes from 4 up to 12 flange widths of 1 1 2 up to 4 cut to your specified lengths hole punching available load tables available for all material. Purlins traditionally support the roof deck cladding sheeting and are in turn supported by the principal rafters steel beams etc.