Steel Rafter And Purlin Roof Construction
The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.
Steel rafter and purlin roof construction. This design is a lot stronger and more robust way of making a steel shed. In architecture or structural engineering or building a purlin or purline is a horizontal structural member in a roof. We do recommend it however. An affordable option and easier to lay than shingles tin is the most commonly used type of metal roofing.
The support system for the roof is comprised of ridgepole and rafters or purlins. Boxspan roof frames and rafters are suitable for use with both steel and timber framed homes. Boxspan is extremely efficient in roof framing. Let s take a look at the most common types of metal roofs for houses.
Purlins and girts are used longitudinally to support the roof sheeting which they were originally designed for. Long spans and light weight make architectural such as cathedral ceilings exposed trusses and roomy lofts more feasible than ever. 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. Rafters to support the metal strap along its whole.
Also known as sheeting rails purlins create the roofing members of the secondary framing of a steel building. Note that these are normally only required to trussed rafter roofs and not for traditional purlin and rafter roof construction. Purlins are an important component in a pre engineered steel structural kit. Building control guidance note purlin and rafter roofs timber sizes and construction details.
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. 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. Metal roofing panels rated for architectural use attached to purlins horizontal pieces of wood or metal fastened to roofing trusses are structurally sound when installed according to your roofing manufacturer s instructions and local building codes. 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.
Do all roofing projects require purlins. J l neal subject. These structural supports run perpendicular across the rafter beams. For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet.
They give added support to the roof and also provide a nailing surface for the end panels and drip edge. Purlins are installed horizontally under metal roofs. The purpose of purlins. 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. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top.