Steel Roof Purlins Design

Purlins supporting glazed roof 100 n m 2.

Steel roof purlins design.

They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. Purlins are 2 by 4 feet and are installed much like metal roofing. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. Taller purlins also allow room for increased insulation.

The size of purlins depends on the nature of roof covering supported wind and other loads and the spacing of the trusses. Metal roof purlins are installed horizontally under metal roofs. 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. Do all roofing projects require purlins.

Purlins and girts are used longitudinally to support the roof sheeting which they were originally designed for. They give added support to the roof and also provide a nailing surface for the end panels and drip edge. If your design or local building codes demand extreme spans or snow loads taller purlins may be required. Welded together they can be used as columns braces and ties.

Steeline c purlins are made from quality galvaspan steel and are roll formed to length with holes punched to your specification. The shape of cee purlins does not allow end lapping they are butted together. Engineered purlin metal mart offers a complete line of engineered purlin material. Steeline c purlins are available in different sizes and material strengths to match the design specification of your building.

Generally the following figures may be adopted. Purpose use 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. Purlins are non pressure treated 1 x 4 x 12 lumber that is installed on to the roof in a specific layout pattern and screw pattern. 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.

Purlins supporting corrugated sheeting 80 n m 2. 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 supporting slate roof 120 n m 2. 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.

Rhino metal building purlins and options traditionally rhino steel buildings use 8 to 10 primed red iron c purlins and z purlins.