Hidden Fastener Standing Seam: There is a broad range of panel widths and seam heights that fall into this category. In most cases this profile can be installed on roof decks with as little as a 1/12 pitch all the way up to a vertical mansard. What makes this profile the most desired vertical panel for homes and commercial buildings alike are the hidden fasteners. Fluctuating temperatures throughout the day can cause metal panels to expand and contract as they go from hot to cold. To counter this activity the vertical seams that rise up perpendicular from both ends of a metal panel are held down with clips and screws. After each panel is attached to the deck the next panel’s vertical seams are placed over it and either snap lock together or are seamed mechanically by hand or machine. Thus forming a watertight bond. The clips allow for expansion and contraction of the metal without strain on the fastener. Therefore the fastener (screw) maintains its structural integrity and the roof remains fully adhered to the deck.