An elevated floor has two separate types of floor panels arranged in alternating order on adjustable support legs. Base floor panels and access floor panels are formed from squares of low density oriented strand material having extruded metal cladding strips along the peripheral edges of the squares. The base floor panels include edge cladding strips having a support flange extending outwardly from the base panel peripheral edge. The access panels include a different type of cladding strip designed to seat on the support flange of the base panel cladding strip. Detachable riser beams are provided for assembly of multilevel stepped raised floors.