Abstract: The invention is directed to metal planking used to construct planar surfaces, such as patio, porch and balcony decks, and interior floors and roofs of structures. The metal planking comprises an elongated strut and a slidable cap that covers the strut after the strut is fastened to support members in the structure. The strut includes a first flange and first web spaced apart from a second flange and second web, and a cord extending between the first web and the second web. The cord provides a surface for fastening the strut to the support members of the structure, and the cord includes at least one corrugation extending in an upward direction to a location adjacent the plane of the first and second strut flanges. The slidable cap includes a first hem extending along one edge of the cap, and a second hem extending along the opposite edge of the cap.