Standing seam metal roofing is defined as a ‘concealed’ or ‘secret fix’ fastener metal panel system. Because clips under the sheet hold it down and the sheet is not punctured with fasteners, it remains completely watertight even at very low slopes. Once two panels are engaged, a hand or mechanical seamer is used to bend the edges and ‘seam’ the panels together to lock them firmly in place with no chance of disengagement.