During the past decade, more companies—both building contractors and metal fabricators—have adopted on-site roll forming technology. By roll forming on the job site, they can run panels longer than any semi could handle, and those long panels, with fewer seams, can ultimately give a roof better fit and tightness. In addition, the final metal building almost always varies from the original specs, so last-minute changes are inevitable. Working on-site allows fabricators to roll-form just the amount the customer needs and account for those last-minute changes.
For instance, say a job requires a roof surface that calls for 16-inch-wide panels. Unfortunately, the total roof width isn't a multiple of 16, so the last bit of roof will require a narrower panel.
Consider that there's a 28-in.-wide patch of roof left; slitting and forming at the job site, the fabricator can fill that space with two 14-in. panels—much faster and easier than workers hand-forming the final panels to fit.