Purlins Roof Truss

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.

Purlins roof truss.

A common arrangement is a rafter and purlin system which combines purlins and rafters. An added benefit are the strong lines that purlins create by running parallel to the ridge beam s. Purlins transmit these loads to the trusses. 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.

This article and series of illustrated diagrams shows you all the parts of a basic roof truss king truss and queen truss. Purlins are beams of light sections spanning between trusses carrying dead load of roof live load and wind load. Purlins 24 oc are typical along with the bottom bracing shown. In post frame construction roof purlins are the members running the lengthwise direction of the building either placed on top of or between the roof trusses or rafters to attach the roof steel or other roof sheathing to.

Adding purlins between heavy timber trusses is an elegant way to reduce the cost of a timber frame roof because purlins permit an increased on center distance between trusses so you purchase fewer trusses. To strengthen the roof system truss clustering cross bracing and wind bracing is recommended at both end of the buildings and every 20 for longer span buildings. The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed. Timber frame truss and purlins.

So i would like some info on purlins. There are many types of roof trusses as wall as many types of roofs more types than there are parts. The roof truss structure and design is integral to roof structural integrity and shape. Generally the purlins are so spaced that they are supported over the top chord joints of the truss.

Along with different truss spacings are how to install roof purlins across or between trusses to support steel roofing. 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. Roof purlin are members used to directly support roof sheeting materials and could be made of timber or steel. Amongst differences are how to space trusses two four eight 12 foot or numerous other possible centers.