Abstract: The panel includes a square base of expanded polystyrene, and has two projecting sides which mate with the undercut sides of two identical adjacent panels. All four sides of the base are bevelled slightly, and the front face defines intersecting grooves so that a polymer fortified concrete facing can be applied to the front of the base without warping the base as the concrete shrinks during hardening. An acrylic binder, with quartz granules carried thereon is provided over the concrete facing to enhance the appearance of the panel, and to improve its resistance to impact.