Standing seam is the longest installed type of metal roof, dating back to when metal roofing was handmade from metal sheets. At that time most sheets were made of copper, bronze or tin and still today many church roof constructions show copper roofs with an air of nobility with their natural patina. Today, standing seam roofs are commercially manufactured by hundreds of big manufacturers with their own roll-forming machines. Standing seam profiles have been under an ongoing development process to offer more than just a symmetric cladding product. Today various asymmetric shapes (convex curved, tapered-convex curved, tapered, tapered-concave curved, concave curved and of course straight) can be produced to almost any desired sheet allowing the decking of complex roof constructions.
The illustration above show example cross-sections and asymmetric applications.