Composite Floor Beam

A composite floor beam for use in a workpiece structure having at least one floor and at least one ceiling and utilities therein, the composite floor beam comprising an upper part made from a first material comprising wood extending substantially along the length of the beam and a lower part made from a second material comprising metal extending substantially along the length of the beam, wherein the upper part comprises an upper surface and a lower surface, wherein the lower part comprises an upper surface and a lower surface, wherein the upper surface of the upper part is designed to be arranged horizontally to support the workpiece floor above, wherein the upper surface of the upper part is parallel to the lower surface of the lower part, wherein the lower surface of the lower part is designed to be arranged horizontally for attachment to the workpiece ceiling below, wherein at least one of the lower surface of the upper part and the upper surface of the lower part is irregular, and wherein the lower surface of the upper part and the upper surface of the lower part define apertures between them for the workpiece utilities, the apertures passing from a first side of the beam to a second side of the beam transverse to the direction of the length of the beam and between the ends of the beam.