Through-wall brick are called different names by different manufacturers. But they all have one thing in common: a finished surface on both faces. Hollow through-wall units must meet ASTM C 652; solid units must meet ASTM C 216. Generally, through-wall brick is a load-bearing brick larger than standard brick and used in a single-wythe wall. The walls usually are reinforced and grouted to increase tensile and shear strength. The nominal through-wall dimension is usually 4, 6, 8, 10, or 12 inches and the bricks can be up to 16 inches long. Hollow units have more than 25% cored area. LESS TIME AND MONEY Architects specify through-wall brick for several reasons: low cost, high strength, quick construction, and a ready-made finish on both wall faces. Single-wythe brick walls go up fast because the units are larger and two wythes aren't needed. REINFORCING ADDS STRENGTH In seismic areas and in areas with high winds, single-wythe brick walls must be reinforced and grouted. The ultimate strength of the wall depends on the grout, amount of rebar, and the compressive strength of the brickwork.