Standing seam roof systems use panels that have raised seams and are supported by clips that are fastened to the roof purlins, but the attachment between the roof panel and the clip does not require a fastener. The clip fasteners are concealed providing a reliable weathertight roof system.
Standing seam roof systems are available in many different profiles, and depending on the product, the seams may simply snap together, or they may require the use of a seamer machine to mechanically bend and seal the seams.
Read more about Standing Seam vs Screw Down Roof Systems.