A roofing system is installed over the top of existing corrugated metal roofs or over the top of low profile ribbed metal roofs as a retrofit roofing system. The system uses a clip specifically designed for corrugated and other forms of low-profile ribbed metal roof panels. The clip spans a single raised corrugation or single raised rib to provide a secure support for a roofing system to be disposed above the existing roof. The clips may be disposed at a plurality of locations along a purlin and are secured to the purlin through the existing roof panels with connectors. The connectors pass through spaced curved feet of the clip which fit into the spaced depressions of the corrugated roofing panel or the spaces adjacent to the low profile rib.