Because brick veneer on buildings is what the public sees, the construction tolerances for it are much stricter than those for the concrete or steel building frame that supports it. Brick veneer should vary no more than 1/2 inch from plumb either way, according to the Brick Institute of America. Because buildings are constructed according to these tolerances, the cavity between the exterior brick and the interior backup block and building frame almost always varies in width. It's the masonry contractor who has to deal with the problem. WAYS THAT DON'T WORK The masonry contractor might simply bolt the supporting shelf angle to the frame and let the brick hang over the shelf angle farther. The contractor also might decide to just use different sized shelf angles--large ones where the cavity is wide and small ones where the cavity is narrow. These methods cause problems. PROPER SHIMS, SHELF ANGLES, AND ANCHOR BOLTS Correct use of shims is critical in achieving a proper connection. The amount of shim provided should not exceed 1 inch. Most tolerance differences can be kept within this distance. A 5x5x3/8-inch shelf angle should adequately support most brick veneer walls up to 15 feet high. The anchor bolt should be located near the top of the angle to minimize the pullout forces on it. The anchor embedded in the concrete frame should have a stirrup to help it resist pullout forces.