Roofing Roof Framing Plan C Purlins

Under purlins were typically propped off internal walls.

Roofing roof framing plan c purlins.

The steel purlins are in turn supported by rafters or walls. Engineered purlin metal mart offers a complete line of engineered purlin material. The purlins support the long span steel roofing but before the roof itself is put on a metal facia frame is installed around the perimeter of the roof. Do all roofing projects require purlins.

We do recommend it however. 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. Galvanized cee purlins in steel construction the term purlin typically refers to roof framing members that span parallel to the building eave and support the roof decking or sheeting. Here is a closer look at common roofing terms.

When repairing or replacing a roof it pays to be familiar with these terms. Purlins are 2 by 4 feet and are installed much like metal roofing. 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.

They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. In traditional timber truss construction purlins rest on the principal rafters of the truss. The facia frame may also supports the soffit. Dead load will be the actual weight of the roof steel and the roof 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. This frame supports and is hidden by a metal facia board. 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. In small roofs purlins are inserted between the rafters and nailed through the rafters.

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. They give added support to the roof and also provide a nailing surface for the end panels and drip edge. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. Our frame is welded up of 1 x 1 angle bar and 1 flat bar.

In large buildings where heavy trusses are used the purlins are continuous members that rest. Includes illustrations that show roofs have hip rafters ridge boards jack rafters and more. Metal roof purlins are installed horizontally under metal roofs. For example an 8 x 4 under purlin would support the center of a row of 6 x 2 rafters that in turn would support 3 x 2 roof purlins to which the roof cladding was fixed.