Steel Rafter And Purlin Roof Construction

The rafter and wall plate.

Steel rafter and purlin roof construction.

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. For many applications a layer of plywood underneath your metal roofing is an unnecessary expense. 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.

J l neal subject. The typical spacing standards for residential and commercial buildings are about 1 to 2 foot. Boxspan roof frames and rafters are suitable for use with both steel and timber framed homes. They give added support to the roof and also provide a nailing surface for the end panels and drip edge.

Also known as sheeting rails purlins create the roofing members of the secondary framing of a steel building. Purlins and girts are used longitudinally to support the roof sheeting which they were originally designed for. Boxspan is extremely efficient in roof framing. Whether you are looking to install a metal roof on a shed or a house it s important to know the difference in the various types of metal roofs available.

Building control guidance note purlin and rafter roofs timber sizes and construction details. Rafters to support the metal strap along its whole. 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. We do recommend it however.

The purpose of purlins. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. These structural supports run perpendicular across the rafter beams. This design is a lot stronger and more robust way of making a steel shed.

Roof frames rafters roof beams lintels. Do all roofing projects require purlins. Long spans and light weight make architectural such as cathedral ceilings exposed trusses and roomy lofts more feasible than ever. Purlins support the loads from the roof deck or sheathing and are supported by the principal rafters and or the building walls steel beams etc.

The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. Let s take a look at the most common types of metal roofs for houses. Purlins are an important component in a pre engineered steel structural kit. Purlins are installed horizontally under metal roofs.

For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. Note that these are normally only required to trussed rafter roofs and not for traditional purlin and rafter roof construction.