The rise is the height of porch, or the steps, that you will need. A run is the total length of the steps from the edge of the porch to where the steps end. Stringers are usually 2 x 12-inch (5. 1 x 30. 5 cm) treated wood boards to which the tread and riser are attached. You can buy pre-cut stringers at most lumber or home improvement stores. The treads are 2 x 6-inch (5. 1 x 15. 2 cm) treated wood boards that lay parallel to each other to form a single step that is approximately 10. 5 inches (26. 7 cm) wide. You will attach a riser, a 1 x 8-inch (2. 5 X 20. 3 cm) board, resembling a toe board, to the back or upright section of the step. Most steps are 6 to 8 inches (15. 2 to 20. 3 cm) in height.
Take the total height and divide it by the height of the riser. This tells you the number of steps you will need. Remember that the riser height averages between 6 and 8 inches (15. 2 to 20. 3 cm) high. As an example, a height of 35 inches (88. 9 cm) divided by a 7-inch (17. 8 cm) riser will result in 5 equal steps. Don’t forget to consider the blocking or apron at the bottom of the stairs to support the stairs.
Have the square set up by clamping a straight edge at the 7-inch (17. 8 cm) mark on the short outside section of the square. The long outside section of the square, at that point, will be at the 10. 5-inch (26. 7 cm) mark.
Check to make sure that they are plumb and level to each other as you go. The bottoms of the stringers need to be sitting on a concrete pad or brick base and not on bare ground.
