How to lay out stairs with a framing square

Step by step, worked from a 44 in total rise

A 44 in finished floor-to-floor rise. The stair solver turns that into the riser count, riser height, and tread depth below; every figure is computed by the same code the app runs, not typed in. Those two numbers are your gauge settings.

1. 01

   Start from the computed riser and tread

   Measure the total rise plumb, floor to floor, and run it through the calculator. A 44 in rise comes back as the layout in the table below. The riser height goes on the square's tongue (the short arm); the tread depth goes on the body (the long arm). Everything after this is repetition.

2. 02

   Clamp the stair gauges on the square

   Stair gauges are the little hexagonal stops that bolt to the edge of a framing square. Set one on the tongue at the riser height and one on the body at the tread depth, tighten both, and check them with a tape before you trust them. They keep the square at the same rise and run for every step.

3. 03

   Scribe the first step

   Lay the square on the stringer stock, crown up, near one end, so both gauges bear against the top edge of the board. The tongue now points at the riser, the body at the tread. Draw a line along the outside of each arm. That corner is your first tread-and-riser.

4. 04

   Walk the square down the board

   Slide the square along the board until the tongue gauge sits exactly where the last tread line ended, gauges still against the edge, and scribe again. Repeat one scribe per tread. A 44 in rise steps off this many treads, so you make that many marks, each identical because the gauges never move.

5. 05

   Mark the top plumb and bottom level cuts

   At the top, extend the last riser line down the full board for the plumb cut where the stringer meets the header. At the bottom, the level cut runs along the last tread line where the stringer lands on the slab or landing.

6. 06

   Drop the stringer by one tread thickness

   The bottom riser reads full height on the board, but once the treads sit on top, the first step ends up a tread's thickness too tall and the last a tread's thickness too short. Cut the bottom level line up by the thickness of one tread (3/4 in for most stock, 1 in for 5/4) so every riser finishes equal. Skipping this is the classic first-and-last-step trip.

Common questions

What are stair gauges and do I need them?

Stair gauges are hexagonal brass or steel stops that clamp to a framing square at a set mark. One holds the riser height on the tongue, one holds the tread depth on the body. They are not strictly required, but without them you realign the square by eye on every step and the risers drift out of the 3/8 in code tolerance.

What is the step-off method?

It is walking the framing square down the stringer one step at a time, gauges riding the board edge, scribing a tread and riser at each position. Because the gauges fix the rise and run, every step is identical, and the number of steps equals the tread count from the calculator.

Why do you drop the stringer by a tread thickness?

Because the treads add their own thickness on top of the stringer. If you cut the bottom riser to full height, the first step lands one tread thickness too tall once the tread is on. Trimming the bottom by one tread thickness moves that thickness from the first riser to the last so all of them come out equal.

Is a framing square accurate enough for stairs?

Yes, when the gauges are set to measured numbers and checked with a tape. The square repeats the same rise and run every step, which is exactly what the code uniformity rule wants. The place errors creep in is the gauge setting, so verify it once and the rest of the flight follows.