Lay a piece of plywood on the landing at the spot where the steps will be installed. Run a tape measure from the top edge of the plywood to the designated area for the stairs to reach. Divide this number by 7 inches, the standard rise for stairs, to determine the number of stairs needed. For example, if the total measurement is 56, eight stairs are needed. Then measure from the top of the plywood piece straight to the ground. This is the needed height for the first step.
Measure the required height for the first step along the right edge of a piece of plywood. Measure upward from the bottom of the plywood sheet and mark the spot. From that spot, measure 10 inches to the left, which is the height of a standard step. Use a level to draw a straight line between the spots. Now measure straight down 7 inches. Use the level to connect the second marks in a straight line. Repeat this process across the plywood for the required number of steps.
Cut along the drawn lines with a circular saw. Cut off any remaining board straight across at the last mark. You now have a solid stringer that will go from the landing to the top of the stairs. This will add stability and strength to the stairs. Use the first stringer, as a pattern, to cut additional stringers. Create one plywood stringer for each foot of the width of the stairs.
Attach the stringers to the landing with L-brackets. Space the stringers a foot apart and align them with the landing at the top. Secure an L-bracket onto each side of the stringers.
Create the Steps and Risers
Turn a sheet of plywood sideways and measure across the width of the stairs. Draw a line all the way down the sheet with a level and cut the plywood along this line.
Measure 10 inches from the top of the cut plywood and make a mark. Draw a line across the plywood at this mark with the level to ensure it is straight. Repeat this for each step needed. Cut out the steps with a circular saw. Measure 6 1/4 inches from the top of the cut wood and mark it. This is for the riser. Mark the lines with the level. Create as many risers as needed.
Nail the risers in place. Begin at the top. Nail the riser so 3/4-inch remains above the step area. Use 3-inch nails, two on each board, for each riser.
Nail the steps in place. Slide each step under the corresponding riser and use 3-inch nails, two in each board per riser.
Things You Will Need
- 3/4-inch plywood
- Measuring tape
- Circular saw
- 3-inch nails
- Smooth the edges of the stairs with 220-grit sandpaper. Paint or varnish the stairs to seal and protect them.