Compared with structural steel, masonry materials require less energy to produce. Masons require less technical training than workers who build with structural steel or reinforced concrete. And masonry is multifunctional, in that placing the units provides for closure, structure, and finish in one. However, masonry's cost-effectiveness could be enhanced further by eliminating one of its traditional components, mortar. Over the past 20 years, researchers have developed a number of mortarless masonry systems using block that interlock to provide leveling and alignment. Though still uncommon, these systems could be used to construct strong, durable, and cost-effective buildings. Self-aligning concrete masonry systems that use minimal amounts of mortar offer several potential benefits that could improve masonry's overall effectiveness. Some of these benefits include;problems associated with mortared joints would no longer be a factor, quality control of the assembly would lie with the manufacturer of the interlocking block, using interlocking units without mortar, the mason could put more units in the wall in a given period of time, units could be placed by semi-skilled and unskilled labor with proper guidance, and floor and roof loads could be placed on wall assemblies without waiting for mortar to cure, thus speeding assembly.