How to Frame Steps in Basement

Make Stringers and Treads

• 1

  To determine the slope of your stairs, measure the distance from the basement floor to the first floor. If each rise is 7 inches high, divide this distance by seven to get the number of rises. Because the top floor is the first tread, subtract one to give you the number of treads or steps. The width of the treads is called the run. The length of the run and the height of the rise will give you the slope of your stairs.

• 2

  The treads will fit on notches cut into 2-by-12-inch supports called stringers. You’ll need three stringers to support the treads, one on each side of your stairs and one in the center. Since a 2-by-12 is actually 11-1/4 inches wide, each tread will be 10-1/4 inches wide. Use your square to measure the tread and rise of one step. Cut out one piece to use as a cut-out model.

• 3

  Using your cut-out model, trace and cut matching notches for the treads on all three stringers. If you have a concrete floor, rest the bottom of the stairs on a treated wood 2 inches thick, plus a 1-1/2 inch tread board. For that reason, cut the bottom rise 3 inches less than the others.

• 4

  To make the rise of the top tread the same as the rest, add 1-1/2 inches to the rise leading to the floor.

Assemble the Stairs

• 5

  Nail the stringer bottoms to a plank 2 inches thick. Nail the stringer tops to a temporary 2-by-4.

• 6

  Raise the stringers into place on your basement floor. Nail the inside stringer to the wall stud by the first floor with 10d nails. Remove the temporary 2-by-4, then nail the other two stringers to wall studs. Nail a 2-by-10 across the top to keep the stringers rigid while you work.

• 7

  Glue the bottom tread to the stringers and secure it with a 3-inch screw on each stringer. Flank each screw with 6d nails.

• 8

  Adding one tread at a time, work your way from the bottom of the stairs to the top.