Abstract: A system for interlocking the edges and corners of adjacent panels of a pedestal supported, elevated floor construction. Edge and corner clamp units are put in place after set-up of the panels. The edge clamp units include a lower elongated element which drops through a similarly shaped gap between adjacent panels and is then rotated 90.degree. out of alignment. A screw turned from the space above the floor draws the lower clamp element towards an upper clamp element to grip and interlock intervening edges of the adjacent panels. Adjacent corners of four panels are interlocked to a supporting pedestal by an overlying clamp plate. This corner clamp plate is releasably secured to the pedestal by an individual screw which is also tightened from the space above the floor.