Modular hollow floor panels with integral ducting

A modular panel, which in use is laid in an extended array over a supporting sub-surface to form a hollow floor, wall or ceiling suitable for reticulating electrical, optio-fibre, hydraulic or other conduit, and which comprises an upper load bearing deck which overlies structural support elements which form an interstitial duct zone between the deck and a supporting sub-surface, wherein the elements define a lower duct zone which is partitioned by lateral ribs to form a set of lateral ducts running from one side of the panel to another, an upper duct zone which is partitioned by longitudinal ribs to form a set of longitudinal ducts running from one end of the panel to another, said longitudinal ducts having an imperforate lower surface, and said modular panel also includes a set of vertical ducts adjacent to said imperforate lower surface of said longitudinal ducts which open onto the lower, lateral, ducts and into the upper, longitudinal ducts, wherein each of the lateral, longitudinal, and vertical duct sets is composed of two or more sub-sets of ducts and only corresponding ones of each sub-set of the lateral, longitudinal and vertical ducts are in communication, each of the lower, lateral, ducts being in communication with an upper, longitudinal, duct of a corresponding sub-set through a vertical duct of that corresponding sub-set.