Autoclaved Aerated Concrete ACC HelpAAC. Blocks . o First course is laid and leveled. Blocks are stacked together with thinbed mortar in a running bond with a minimum of 6in. overlap. o Walls are plumbed, leveled, and squared with a rubber mallet. o Openings and odd angles are cut with a handsaw or bandsaw. o Reinforcement locations are determined, rebar placed, and grouting occurs.