Abstract: A building element (1) comprising an outer sheath and an inner core, the sheath being formed of a material having a greater tensile strength than compressive strength and the core having a greater compressive strength than tensile strength; wherein the outer sheath is longitudinally extending and has a first face (7) and a second face (8) which are spaced apart, first (9) and second (21) edges and a first and second end; wherein the first face (7) and the second face (8) are joined at the first (9) and second (21) edges to form the outer sheath as a continuous body, and wherein the first edge (9) and the second edge (21) are so shaped that the first edge (9) of one such building element (1) is adapted to locate in the second edge (21) of another such building element (1).