Air tight access floor assembly

An air tight panel support assembly for an access floor having a plurality of floor panels, the assembly comprising first and second pedestals for supporting a floor panel at respective first and second corners of the panel, each pedestal including a head portion having a platform upon which a corner of the panel is received, a stringer supported at a first end thereof by the first pedestal and at a second end thereof by the second pedestal, wherein the stringer has sealing material at its upper side for providing an air tight seal against the underside edges of adjacent floor panels, and the stringer is formed as a substantially U-shaped channel between a clip at the first end and a clip at the second end thereof, and wherein the platform comprises a cruciform boss and a cruciform divider panel having noise attenuation and vibration dampening properties, the divider panel being secured upon the cruciform boss, whereby the divider panel receives thereupon the corner of one or more floor panels such that the floor panel simultaneously engages the stringer at the edge of the floor panel and the cruciform divider panel at the corner of the floor panel, each of the first and second ends of the stringer includes said clip for releasably engaging a respective slot and that the slots are formed in the head portion of the pedestals and the openings of the slots are sunk below the cruciform divider panel so that, when a clip of a stringer releasably engages any one of the slots, the stringer is flush mounted on the pedestal such that the upper side of the stringer is flush with the cruciform divider panel to define a generally planar surface.