Concrete building blocks

Interfitting building blocks for wall construction, including straight stretcher blocks for constructing courses, and corner blocks, each said stretcher block comprising a building block having opposite first and second ends and comprising first and second substantiallycongruent rectangular side panels extending between said ends of said block, said panels being joined together by at least one web extending transverse to said panels, said panels each having vertical end edges at the respective first and second ends of the building block, the end edges being notched to interfit with end edges of panels of an adjacent block in a vertical joint therewith, the notches being vertically extending on the respective end edges and being disposed such that at the first end of said block, the notch of the first panel is on an inside corner and the notch on the second panel is on an outside corner, and such that at the second end of said block, the notch on the first panel is on an outside corner and the notch on the second panel is on an inside corner, each said panel including a lower edge and an outer surface;

• the lower edge of each panel being provided with a downwardly projecting lip substantially adjacent said outer surface, said block further having an upper side, portions of said upper side of said block being spaced inwardlyfrom said outer surface of said panels projecting upwardly, whereby one said block laid on another said block will interfit therewith each said corner block having opposed first and second ends and comprising spaced apart first and second substantially congruent rectangular side panels, each said side panel having an outer surface, an end panel joining said side panels at the first end of said corner block, and a web extending between said side panels spaced inwardly from the second end of said block, the end edges of said side panels adjacent said web being notched to interfit with the end edges of a said stretcher block in a vertical joint therewith, one said side panel being provided on its outer surfacewith a pair of vertically extending grooves spaced apart so as to interfit with the end edges of said first end of a said stretcher block, and the opposed side panel being provided on its outer surface with a pair of vertically extending grooves spaced apart so as to interfit with the end edges of the second end of one said stretcher block, whereby a T-shaped construction, with a flush outer surface, can be formed with a corner block and a pair of stretcher blocks interfit with the corner block at right angles therto, each said side panel of a said corner block having a lower edge, the lower edge of each said side panel being provided with a downwardly projecting lip substantially adjacent the outer surface, said lip of each said side panel being notched adjacent the end panel and at a point inwardly thereof corresponding to the width of one said block, said corner block also having an upperside, portions of said upper side of said corner block spaced inwardly from said outer surfaceof each said side panel projecting upwardly, to interfit with the notches in the lips of the lower edges of the side panels of another of said corner blocks when a pair of the corner blocks are laid on one another at right angles.