Method of casting floors and ceilings of buildings and a panel for use therein

A method of casting floors and ceilings of buildings, comprising the steps of (a) forming a frame or ribbing of parallel beams extending across the whole length or width of the floor, said beams being of an open framework construction to allow concrete to pass therethrough, (b) supporting panels between adjacent beams by means of shoulders extending along two opposed edges of each panel engaging the beams, the bottom of the shoulders being at a height above the base of the panel, (c) temporarily securing flat bridging means against the bases of the panels to form continuous bridges spanning the gaps containing the beams between adjacent panels, (d) pouring concrete over the structure comprising the beams and panels to form, when set, a composite cast floor/ceiling having a substantially smooth and continuous lower surface, and (e) removing the bridging means, wherein each bridging means is pressed against the bases of the panels on opposed sides of the gap bridged by the bridging means partly by fixing means secured to the panels, wherein the said fixing means comprises one or more clamps anchored to the panels on opposed sides of the gap bridged by the bridging means, and wherein each clamp is anchored by means of a bolt co-operating with a nut embedded within the respective panel and accessible through a communicating bore in the base of the panel.