A roof panel includes a planar body having top and bottom edges, with a downturn edge extending therebetween, and an opposing channel edge. The downturn edge overlays a channel edge of an adjacent panel. The bottom edge overlays a top edge of another adjacent panel. A plurality of courses extends between the channel and downturn edges. Each course includes a nesting ridge to receive the downturn edge of an adjacent panel and to position a top surface of the panel flush with adjacent panels. Surface channels and contoured ridges are defined within each course. A drain aperture of the drip edge aligns with an adjacent channel edge to direct material through the drain aperture and onto adjacent panels. A gable member engages an edge when the panel has one or fewer laterally adjacent panels, wherein the gable member is flush with the adjacent planar body.

A lightweight interlocking metal roof system for installation onto a steep or inclined structure roof either directly over the roof decking material or over an existing shingle roofing system, with the metal roofing system installed from the roof ridgeline down to the drip edge of the roof gutter. Cooperating outwardly extending flanges and receiving pockets for capturing and interlocking the metal panels of the roofing system create an interlock between and among panel members with overlying edge ends configured to be resistant to lift up due to winds either across the roof or along the roof edges.

A roofing system, including at least a first, second, and third metal roofing shingle installed on a roof deck adjacent to a plurality of photovoltaic modules, the first and second metal roofing shingles installed in a first row on the roof deck, the third metal roofing shingle installed in a second row on the roof deck, each of the metal roofing shingles including a metal layer and a cover layer, the metal layer including a conductive metal, the cover layer overlaying a portion of the metal layer and exposing at least one side lap of the metal layer, the side lap of the metal layer of the second metal roofing shingle overlaying and in electrical contact with the side lap of the metal layer of the first metal roofing shingle, to form a first grounding path, and the third metal roofing shingle in electrical contact with the first metal roofing shingle, to form a second grounding path.

A roofing system, including at least a first, second, and third metal roofing shingle installed on a roof deck adjacent to a plurality of photovoltaic modules, the first and second metal roofing shingles installed in a first row on the roof deck, the third metal roofing shingle installed in a second row on the roof deck, each of the metal roofing shingles including a metal layer and a cover layer, the metal layer including a conductive metal, the cover layer overlaying a portion of the metal layer and exposing at least one side lap of the metal layer, the side lap of the metal layer of the second metal roofing shingle overlaying and in electrical contact with the side lap of the metal layer of the first metal roofing shingle, to form a first grounding path, and the third metal roofing shingle in electrical contact with the first metal roofing shingle, to form a second grounding path.