Z-purlin question
Z-purlin question
(OP)
Roofer wants to retro fit a new roof over an existing roof system attached to 14 Ga. z-purlins (8x3). Span is 25 feet spaced at 5' o.c. I don't know what is going on but I can't seem to get the purlins to check out. New roof system is only adding about 2.5 psf and the existing roof is about the same. I am using a standard LL of 20 psf but I can't wrap my head around how the original designer would of sized these members for such a small dead load. Steel frame building was built back in 1980...am I missing something here?






RE: Z-purlin question
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Z-purlin question
RE: Z-purlin question
DaveAtkins
RE: Z-purlin question
DaveAtkins