Roof Framing Plan Roofing C Purlins

For sake of discussion we will assume a minimal roof snow load of 20 psf pounds per square foot and a 4 12 roof slope.

Roof framing plan roofing c purlins.

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. C section purlins or cee section purlins are designed to form the walls and floor joists of a building shell structure making them also ideal for supporting beams needed for mezzanine flooring. A common arrangement is a rafter and purlin system which combines purlins and rafters. Dead load will be the actual weight of the roof steel and the roof purlins.

Purlins are 2 by 4 feet and are installed much like metal roofing. In small roofs purlins are inserted between the rafters and nailed through the rafters. They give added support to the roof and also provide a nailing surface for the end panels and drip edge. Besides providing support for the roof rafters and purlins add to the interior beauty so you often see log purlins and rafters that match the wall logs.

Welded together they can be used as columns braces and ties. The roof support system is a ridgepole and either rafters which run perpendicular from the top of the walls to the ridge or purlins which run parallel to the ridge. 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. The shape of cee purlins does not allow end lapping they are butted together.

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. The cos of the purlin spacing is because the load on the purlins is vertical and the purlin spacing is with the run of the roof. Do all roofing projects require purlins.

Purlins purlins are used in roof construction to support corrugated sheet metal if it is used or to support the sheathing of roofs framed with trusses. We do recommend it however. In addition our c section purlins can also be used for door framing roof trimming window trimming parapet rails and side rails also see z purlins page. In structural steel or aluminum construction purlins usually w shapes or channels transfer roof loads to the major structural elements supporting the roof.

Engineered purlin metal mart offers a complete line of engineered purlin material. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. 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 traditionally support the roof deck cladding sheeting and are in turn supported by the principal rafters steel beams etc.

A traditional purlin strictly by definition is a horizontal structural member in a roof.