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This practice covers material, workmanship, and construction procedures for applying surface bonded mortar to both sides of dry stacked concrete masonry units. Mortar shall be mixed and shall be selected in accordance with the proportion specification prescribed. Shims shall be corrosion-resistant metal or plastic with a required minimum compressive strength. Courses of concrete masonry units between the leveling courses shall be placed without mortar on the bed or head joints. Place units in running bond. Remove burrs and butt blocks tightly. Use shims, mortar, or surface bonding mortar to plum and level individual units when necessary. Use clean mixing equipment and water free of deleterious amounts of acid, alkali, and organic materials. Mix only full bag multiples of material to overcome any segregation of ingredients. Mixing time shall be kept to a minimum, as over mixing may cause damage to the fibers. Before applying surface bonding mortar, wet the wall uniformly with water to prevent excessive suction of water from the surface bonding mortar. Trowel- or spray-apply surface bonding mortar to both sides of dry-stacked concrete masonry units. When a second coat of surface bonding mortar is to be applied, the first coat shall have taken its initial set. Dampen the wall with a water mist after a specified time, but within a day of application of surface bonding mortar. The top of the walls shall be covered with a nonstaining, waterproof covering to prevent moisture from entering the wall until the top is permanently protected.