Insulated cementitious building block system

An insulated masonry building block system for use in a mortar set masonry wall comprising:

• first, second and third spaced, parallel, rectangular face shells, with said second face shell located intermediate said first and third face shells, wherein said first, second and third rectangular face shells each have a bottom edge located in a first horizontal plane and said first, second and third rectangular face shells each have a top edge located in a second horizontal plane;
• first and second end cross webs connecting the ends of said first and second face shells in first and second respective planes, each of said first and second end cross webs having a notch therein extending a predetermined distance from the top thereof toward the bottom thereof;
• first and second spaced intermediate cross webs located on spaced planes between the first and second planes of said first and second end cross webs and connecting said second and third face shells, said intermediate cross webs each having a notch therein extending from the top thereof a predetermined distance toward the bottom thereof;
• a first insulating insert dimensioned to substantially fill the space between said first and second face shells and said first and second end cross webs, said first insulating insert having top and bottom edges, with end protrusions extending outwardly at the top edge thereof to fit into the notches in said first and second end cross webs, said end protrusions having cutouts in bottoms thereof to accommodate mortar crumbs, said first insulating insert having a longitudinal notch along the entire bottom edge and a longitudinal notch along the entire top edge wherein said longitudinal notch along the entire bottom edge is dimensioned to fit into a top longitudinal notch of a neighboring one of said first insulating inserts creating an overlap that serves to (i) insulate against temperature transfer and (ii) provide a sound barrier.