Abstract: A concrete-based building block has an integrally-formed wooden attachment layer on one or both exterior surfaces of the block that can receive and hold a penetrating fastener such as a nail, screw, staple, or the like. This allows surficial coverings such as wallboard, siding or other materials to be easily attached to a block wall made of the building blocks. The block includes substantially semi-cylindrical concave portions that form a cross-linked structure of channels when the blocks are assembled into a wall. Once the blocks have been stacked in place in a wall, grout or other suitable filling material is poured into the cross-linked structure of channels. When the filling material hardens, the blocks are locked together. Surficial covering materials may then be nailed, screwed, or stapled directly to the attachment layer of the blocks.