Insert two equally spaced nails into the rafter.
Purlin shed roof.
The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed.
Thirdly purlins add additional support between the spans of the individual framing bays.
Secondly purlins tie the rafters together stabilizing and strengthening the structure s rigid framing.
Metal building roof purlins provide three structural functions.
Purlin roof structure civil engineering design in architecture or structural engineering or building a purlin or purline is a horizontal structural member in a roof.
Fasten the purlin with 16d common nails into each vertical rafter.
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.
First the purlins support the roof.
Spacing is typically 24 on center in low snow loads and is reduced based upon truss span and snow load.
Snap a chalk line horizontally across the roof two feet down from the top.
Lay the first purlin at the ridge of the roof down to the chalk line beginning at either corner.