A composite building panel includes: a central body comprised of an expanded polymer matrix having a first face and an opposing second face, a top surface and an opposing bottom surface, and a first side surface and an opposing second side surface; and a furring member extending horizontally across the central body between the first side surface and the second side surface proximate to the top surface. The furring member comprises: a bottom portion having at least one expansion hole such that the expanded polymer matrix extends therethrough, thereby embedding the bottom portion in the expanded polymer matrix; a first side portion extending perpendicularly from the bottom portion; and a second side portion extending perpendicularly from the bottom surface. One of the side portions extends from the bottom portion beyond the top surface of the central body.