I've got the trusses set on a new pole barn. After initially setting the trusses we pulled a string across from gable to gable (about two feet up from the end of the tails) and then slid the remaining trusses forward or back until they just touched the string. It would seem, in theory, that I would now have a perfectly flat plane for the roof. Yea, right. [img]/forums/images/icons/frown.gif[/img] So now that theory has gone out the window, and reality has once again taken control, the question is just how flat do I need to shim the purllins? I'm going to use metal roofing, probably one of the styles that mimic the classic old standing seam roofs. If I pull a string from gable to gable on each run and shim the purlins to it, how close do I need to get? 1/4"? 1/8"? And yes, I know, I'm being anal-retentive, and a perfectionist. But it's a whole lot easier to shim them now than to try to go back and do it after the roof is on.
Thanks,
Kevin