How to Build a U-Shaped Stairway
- 1). Calculate the number of treads you will have in your stairway. Measure from the finished floor of one level to the next with a measuring tape, then divide this number by 7.5 (the standard rise height for stairs). Round your number up to the nearest whole number; this number represented the number of treads you will need, plus one landing. For example, if your finished floor-to-finished-floor measurement was 120 inches, divide this number by 7.5 for a quotient of 16, which equals 15 treads and one landing.
- 2). Find a location for your landing --- most often at or near the center of the rise of the staircase. In the example of 15 steps and one landing, you would have seven treads going one direction, then the landing and then eight treads going in the opposite direction to complete the U shape.
- 3). Calculate the run and width of your staircase. Multiply the number of treads before your landing by the depth of your tread. Add this number to your landing depth to determine the run of one leg of your U shape. Repeat the process for the number of treads in the second half of the stairway with the landing depth to determine the run of the second leg of the U. Measure the width of the space where you plan to build your stairway. Subtract the thickness of building materials that will separate the two halves of the U, if needed. Divide the figure in half to determine the width of each of your treads.
- 4). Build the landing, and attach the stringers. Per your staircase design plans, build the landing, including attaching the plywood subflooring. Cut three pieces of 1-by-12-inch dimensional lumber with a saw to the length you determined for the run of the first leg of your U. Following the manufacturer's instructions, attach the universal stair brackets to the dimensional lumber to form the staircase stringer. Attach the stringers from the bottom floor to the landing, positioning the outside stringers at the width you determined for your treads, and the inside stringer in the center of the other two.
- 5). Attach the risers and treads. Use a nail gun to nail the risers and treads to the stringers. Repeat the process for the second leg of the U of your staircase. Attach handrails per your design and per local building codes.
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