How to Cut Stair Risers & Treads

Open Stringer Installation

• 1

  Measure from outside to outside of the stringer pieces. For Risers, measure the distance between the floor or top---horizontal---cut of the step notch and the top cut of the step above. For treads, measure from the front edge of the riser---vertical---cut of the notch to the front edge of the vertical cut in the notch above.

• 2

  Cut risers to the width of the space between stringers from outside to outside and the height of the riser cut of the stringer. Cut treads 1½ wider than the risers and as deep as the tread cut of the stringer plus ¾ inch. Use a miter saw to make the cuts.

• 3

  Rout the edges of the treads on the two short edges and one long edge of both faces of the tread. Set up a 1/4-inch roundover bit with a bearing in your router. Adjust the depth so that the top corner of the roundover curve is flush with the base plate of the router. Clamp the tread to the corner of your work table with a C-clamp so that all three edges are hanging off the table. Run the router counterclockwise around all three sides and flip the tread. Repeat on the opposite face, routing the same three edges.

• 4

  Attach the risers first. Position each stringer against the face of the stringer with the ends flush and the bottom on the tread cut of the riser. Position the treads with the back edge against the face of the riser, centered side to side. Nail through the tread into the top edge of the stringer notch.

Closed Stringer Installation

• 5

  Measure the width between the stringers inside to inside. Measure the tread brace from the front corner of the tread brace where it meets the riser brace to the front of the riser brace above. Measure the riser brace from the top of the tread brace to the top of the tread brace above.

• 6

  Cut risers to fit snugly between the stringers and as tall as the riser brace. Cut treads to fit snugly between stringers and as wide as the tread riser. Use a miter saw to make the cuts.

• 7

  Rout the front edge of the treads as outlined for notched stringer installations. Rout both faces of the front edge only.

• 8

  Install risers first. Fit them between the stringers, against the riser braces. Nail them in place with at least two finis nails on each end. Install treads on top of the tread braces, with the back edge of the tread against the face of the riser. Nail in place as for risers, nailing into the tread brace.