Abstract: A building construction comprised of blocks of substantially rectangular prismatic configuration. The first pair of opposite edges of the blocks are each formed with a first tongue and a first groove of complementary configuration extending in parallel relationship along each edge wherein the first tongue of one edge is opposite the first groove of the other edge. Each of said first pair of edges is formed with a land portion extending between the sides of said edge and the adjacent first tongue or groove. The height of said first tongue above said land portion is greater than the depth of the first groove below said land portion such that on a pair of blocks abutting whereby the first tongue of one edge is snugly received within the first groove of the other edge of another block, the opposing land portions of the blocks are spaced from each other to receive an adhesive for fixing the blocks to each other.