A deck plank is co-extruded from an extrusion die which receives molten plastics materials supplied from three separate plastic extruders to provide the plank with opposite sides having different colors. Preferably, the base plank is extruded from a lower cost material such as reground scrap polyvinylchloride (PVC), and thin PVC cap layers are co-extruded on opposite sides of the base plank in different colors. Opposite edges of each plank have longitudinally extending grooves for receiving hidden fasteners in the form of screws extending through short flat tie pieces or a continuous sealing tie strip projecting into the opposing grooves of adjacent planks.