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.
Roof framing c purlins trusses.
Stock sizes include gables from 20 to 40 wide and lean to styles in 12 and 20 wide.
When they are in hangers the load stress in on the purlins edge but the lateral stress allows the trusses to move independently.
Purlins placed flat will not span eight feet so eliminates this option.
They can also be made out of wood or steel.
An added benefit are the strong lines that purlins create by running parallel to the ridge beam s.
We provide angle iron steel trusses in gable lean to and header styles.
To put it simply purlins are the horizontal roof members of the roof frame.
C channel purlins are manufactured from hi tensile zinc coated steel strips the processing is cold rolled by machine the steel standards of c channel are q195 235 345 which is meaning the yield strength no less than 195 235 345mpa the zinc coating is 60 275g m coating mass.
Trusses most likely on 8 s.
Purlins 24 spacing mike the pole barn guru writes.
On a typical roofing frame layout they reside between the roof truss and the roof panels.