Abstract: A prefabricated reinforced concrete wall structure formed in two parts, the first part including a plurality of walling units spaced apart but in groups over the whole area of the wall, channel shaped spaces between and around the groups of walling elements being configured in a grid formation and being filled by a high strength reinforced concrete cast in and around the group of walling units and constituting a concrete grid as the dominant structural member of the prefabricated wall panel. The walling units and the concrete grid are further supported by a layer of Portland cement based render on both sides of the wall surface, the completed wall structure being significantly lighter in weight and having a lower Portland cement volume in comparison with normal concrete walls of similar structural ability.