Hulas SkyLock standing seam roof system HS-600 in Nepal offers considerable benefits to the roof designer, roof installer, contractor, and building owner. A standing seam metal roof is one of the most durable metal roofing available, lasting up to 50 years. The Key difference is in the design and application –standing seam roofs take full advantage of having concealed fasteners. A standing seam system consists of wide relatively flat metal panels with vertical legs (or ribs) on each end.