Return stair treads are made of 1 inch thick solid wood and available from 36 inches to 96 inches in length. Return treads are typically used in new construction. The staircase must have at least one open stringer to utilize a return tread. When standing at the base of your staircase looking up the staircase the side that has the open stringer is the side that requires a return end on the tread. If both stringers are open you will require a double return tread.