No longer are walls controlled by arbitrary height-to-thickness ratios (h/t). Using grout, steel reinforcement, and the ultimate strength design procedure, engineers and architects are designing masonry walls that are tall, slender, and economical. Both the Basic Building Code (BOCA) and the Uniform Building Code (UBC) recognize the strength design procedure. To change from working stress design and arbitrary h/t ratios to ultimate strength design required an extensive testing program. The tests demonstrated that masonry walls had far more load capacity than anyone realized. Under previous h/t limits, 8-inch-thick masonry walls couldn't be built higher than 16 feet, 8 inches. Under the strength design procedure, they can exceed 30 feet. That's more than an 80% increase in wall height.