Abstract: Constructing building walls from concrete blocks having flattened rectangular facing members held in parallel spaced relation by integral transverse webs spaced from the ends of the block by a distance equal to one-half the distance between the webs and providing a pair of V-shaped reinforcing of receiving notches having straight sides inclined at an angle of substantially 45.degree.. The blocks are stacked in equally staggered courses to define the wall panel and are held in position by a bonding agent securing the confronting surfaces of the blocks to each other with substantially no space therebetween. Vertical reinforcing rods are positioned in the vertically extending openings provided by the aligned webs of the blocks, and horizontal reinforcing rods are supported in the V-shaped notches, with the shape of the notches causing the rods to settle into desired positions on opposite sides of the vertical reinforcing rods.