Mechanically seamed standing seam actually requires less metal material than any other metal roofing system, whether it's double locked or single stage technology needed, depends on your roof slope degree. Metal azimuth pocket (book) folds are raised to create a sweep or simple raised (standing) seam. That same seam, may be flattened or chased in order to create or raise another seam. This method connects perpendicular panels with a seam that diverts water, instead of a hidden joggle cleat metal fastened with hidden screws, where water or ice might scale into hidden fasteners, instead of meeting a folded seam and u-turn down the roof.  Sweep seam is best beneficial to divert water away from chimney or window corner at the top, where many metal roofing systems first show signs of water infiltration and or rust. Connecting the chimney pan and side panel together with a sweep seam with proper technology allows you to choose the path of water, thus choosing which Downspout releases its elements to your property. Specialist' required