US Patent 7174687 Web offset lug dry-stack system

Generally, the invention is a dry stack building block for constructing a masonry wall. The dry stack unit has a front section having an outer surface, an inner surface, a bottom surface, and a top surface. The dry stack unit also has a rear section substantially parallel to the front section having an outer surface, an inner surface, a bottom surface, and a top surface. Two or more webs coupling the inner surface of the front section to the inner surface of the rear section have a top surface and a bottom surface. Two or more pairs of lugs may extend above the top surface of the front section and the top surface of the rear section. Each pair of lugs may have a first lug offset from a second lug in an axis perpendicular to the inner surfaces of the front section and the back section.