Hip Roof Purlin Support

This article describes and illustrates the different types of support that prevents roof sagging and wall bulging at buildings including definitions of collar ties rafter ties and structural ridge beams.

Hip roof purlin support.

In homes with conventional ridges the rafters support the weight of the roof and transmit the roof load. There has been no easy and economical solution to joining a hip to the bottom chord of a girder truss at the same junction as another supported girder truss. Brackets to connect hip trusses to girders uses the pryda hip support bracket has been developed to overcome a common timber connection headache. All angles can be found on the chappell univer.

Hip roofs have hip rafters which are oriented diagonally to the ridge and outside walls. Stabilization typically involves installation of a purlin system. Some of these can support the roof and prevent ridge sagging and wall spreading. Purlins as shown in sample photos below are installed for rafter support.

Roof sheathing decking attaches directly to the purlin with knurled pneumatic fasteners or low profile head self drilling screws. The purlins are supported by vertical or slightly angled bracing. In a rafter and purlin loft roof the purlins provide the most tangible support to the roof and are the largest and strongest timbers in the structure. Under purlins were typically propped off internal walls.

Collar ties rafter ties tension beams structural ridge beams. 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. Adjustable in length the ahep is designed to accommodate a pitch range of 3 12 to 9 12 as a structural purlin and up to 12 12 as an installation lateral restraint and spacer. Crown rafter only found in hipped roofs in which it forms the centre joint between jack rafters.

In lightweight timber roof construction under purlins were used to support rafters over longer spans than the rafters alone could span. Hip rafter in a hip roof these are fixed to the jack rafters.