Project Guide

How to Build Stairs

Determine Staircase Slope
Couple measuring and cutting stairs.

Stairs are made of risers, treads and stringers. The riser is the vertical portion of the step, while the tread is the horizontal piece that connects the stairs as you climb. Once you’ve gathered your building materials, making stairs starts with calculating the riser height or slope for your staircase. 

  • First, use a tape measure to measure the rise, or distance in inches, from the floor to the top of your proposed staircase. Make sure to consider the total thickness of floors including any carpet, padding or other subfloor thickness.
  • Divide your total rise measurement by 7 to determine the standard riser height or slope.

Tip: The best slope for your staircase design will depend on your personal needs, the amount of space available and any applicable building codes in your area.

Prepare Stair Stringers
Two men holding a riser and measuring it.

Stringers or stringer boards keep the stairs secured on either side. Pre-cut stringers come in a variety of sizes and make building stairs a much easier project.

  • Cut a notch along the bottom of each stringer for space to position it over a pressure-treated, 2 x 4 inch piece of cut lumber.
Attach the Stair Stringers
Two men attaching a stair stringer to unfinished staircase.

Attach the stringer securely to the upper tier with common joist hangers.

  • Wedge the 2 x 4 inch piece of lumber between the bottom notches and secure it with wood screws
Install Treads
Man installing treads into unfinished staircase.

After the stringers are attached, install the stair treads and risers.

  • Use a circular saw to cut the treads to the length of each riser.
  • Secure them to the stringers with wood screws. 
  • As you install one riser, position and fasten the corresponding tread so you can carefully climb to the next step for installation. 
  • Repeat the process until you reach the top.
Update an Existing Staircase

You don't need to know how to build stairs from scratch to create a great staircase. If the carpet or wood on your existing staircase has seen better days, try covering its risers and treads with unfinished hardwood. 

  • Measure each riser separately. 
  • Cut each riser, leaving an 8 to 12-degree bevel along the edge where it meets the tread. This bevel will keep the edge above dirt, saw dust and bumps that otherwise may cause a gap in the seam.
  • Nail the riser to the framing beneath it. 
  • Cut the tread to length and turn the width to allow for a 1-inch overhang.
  • Apply wood glue to the step and attach the tread.
  • Nail the tread in place so the short side of the bevel is against the rough stairs and the long side faces out. 
  • Repeat until you reach the top of your staircase.