How to Make Interior Step Stringers

Find Dimensions

• 1

  Take a tape measure and determine the distance between the top of the stairway and the floor. This measurement gives you your total rise.

• 2

  Divide the number you obtained by seven, to determine the number of risers, the vertical part of each step, that you need. Round any fractions up for a shallower staircase and down for a steeper one.

• 3

  Divide the total rise by the number of risers, which gives you the unit rise, the height of each individual riser.

• 4

  Choose a tread depth, also called the unit run, within the building code requirements. Remember that most codes require a tread depth of at least 9 inches, although 10 inches usually makes for a more comfortable user experience. Ensure that the unit run plus the unit rise falls between 17 and 18 inches.

• 5

  Multiply the unit run by the total number of treads, which will be one less than the total number of risers. This number gives your your total run, the horizontal distance the stairs span.

Make Stringer

• 6

  Take a framing square and place it near one end of a 2-by-10 board. Place it so the unit run distance intersects the edge near the end. Shift the framing square so that the unit rise distance intersects the edge also. Draw a pencil outline around the outside of the square.

• 7

  Move the framing square so that the unit run on the square meets the unit rise pencil mark you made at the edge of the board. Ensure that the unit rise distance on the framing square intersects the edge of the board.

• 8

  Draw another outline around the square. Repeat for the number of treads you need.

• 9

  Make a pencil mark at the bottom of the stringer that shortens the length of the first unit run marking by the thickness of one tread.

• 10

  Cut away the excess wood with a circular saw. Ensure that you cut away the wood from inside the framing square when you marked the board.

• 11

  Cut your other stringers using the first board as a template.