Abstract: A wall construction for wire-bound boxes utilizing split cleats in at least one pair of opposing walls, wherein two rectangular panels or mats are aligned in the same wall, the opposing ends of the cleats of the panels being shortened for receiving therebetween an auxiliary support member, the support member being clamped between the opposing ends of the upper and lower cleats when the wires are tightened in the assembly of the walls. A face board or a pair of face boards, bridges the opposing ends of the panels and the auxiliary support member therebetween.