I am going to guess you mean "standing seam", which is a type of metal roofing. This type roofing normally depends on concealed fasteners, is allowed to move in the direction of the ribs, and is not structural.
I've found this to be a handy reference for working with standing seam systems: Link
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.
Many standing seam systems are "structural" in the sense that they will span between purlin rows without an underlying steel deck to support the standing seam panel.
ajh1.
I agree. I meant that standing seam roofing is not part of the primary structural system. It is cladding. Some types of metal roofing are used by some (not me) as diaphragms to distribute lateral loads, but that should not be attempted with standing seam systems.
