Abstract: The present invention provides a composite wall construction including a first wall element extending in a first general plan, a second wall element extending in a second general plan parallel to the first plane and spaced from the first wall element. The first and second wall elements define a space between them and the second wall element has an inner sheet defining one side of the space. A plurality of elongate reinforcing members extend longitudinally vertically within the space and are attached to each of the first and second wall elements. Each reinforcing member is formed of sheet material and has keying formations to facilitate adhesion between the reinforcing member and a settable substance poured into the space. The first wall element has a plurality of spaced-apart vertically extending corrugations forming recesses into which the space extends.