Purlins Of Flat Roofs

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.

Purlins of flat roofs.

If you are planning upon going with edgewise purlins across a single truss you are going to run into an uplift problem. 8 x section modulus of a 4 2 of 1 3125 x fb fiberstress in bending x 1 15 duration of load x 1 15 cr repetitive member factor as the purlins are spaced 24 o c. Image copyright belongs to albion sections limited uk roof purlin are members used to directly support roof sheeting materials and could be made of timber or steel. 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.

Purlins placed flat will not span eight feet so eliminates this option. Trusses most likely on 8 s. Snap a chalk line horizontally across the roof two feet down from the top. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.

Purlins 24 spacing mike the pole barn guru writes. How to install metal roof purlins. Or less x 1 1 cfu the flat use factor for applying the load to the wide face of a member. Flat roofs the recent and more onerous requirements of approved document l of the building regulations relating to energy conservation have shifted the emphasis for thermal efficiency from the building structure to the building envelope.

Run a tape measure from end to end along the rafters of the roof to determine how many purlins will be needed for installation.