Abstract: The present invention provides novel wall construction systems and materials for residential and commercial construction that incorporate grooved lightweight building material units (e.g., blocks, panels, and the like), a plurality of connection devices, a track system, and (injected) polyurethane structural foam. The wall construction system comprises building material units married to a building frame with a plurality of connection devices (e.g., clip fasteners) slidingly retained in a track system that is attached to the building's structural (e.g., load-bearing) framing. The building material units are joined to each other with a suitable binding agent. The cavity between the frame and the building material units is injected with an insulating structural polyurethane foam. The exterior of the wall is finished with a waterproof applied finish such as cementitious stucco. The interior of the wall is amenable to standard finish options.