Stairs for a 42 in rise
Every board for this set of stairs counted, cut and priced before you drive to the lumberyard. The whole plan is on this page. The full plan set to take to the yard is $19.
- Risers
- 6 at 7"
- Treads
- 5 at 10-1/2"
- Total run
- 4' 4-1/2"
- 2x12 stringers
- 4
- Materials
- $239
The list you take to the lumberyard
Every board, sheet and box of nails, packed into the stock lengths the store sells, so nothing is a guess at the counter.
- Lumber
- $173
- Hardware and finish
- $66
- 4PT 2x12 x 8 ft$115.92
- 6PT 2x6 x 8 ft$56.88
- 4Stair stringer connector (each)$25.92
- 1Exterior construction screws 3" (5 lb box)$39.98
Typical Home Depot and Lowe's shelf prices, October 2026. Your store will differ by a few percent.
The drawings
Framing drawn from the same boards the list counts. Hover a member to see what it is.
Cut list
Every piece, how many, and how long. Tape it to the saw.
| Qty | Board | Cut to | Part |
|---|---|---|---|
| 4 | PT 2x12 | 6' 8-3/4" | Stringer6 risers of 7", 5 treads, cut from one board |
| Qty | Board | Cut to | Part |
|---|---|---|---|
| 10 | PT 2x6 | 3' 0" | Tread boardtwo boards per step, 1/4 in apart |
| 1 | PT 2x6 | 2' 9" | Kick plateties the stringer feet together at the bottom |
Which piece comes from which board
10 boards, laid out so the offcuts stay small.
Build it in this order
- 01
Measure the rise
Measure from the top of the deck (or shed floor) straight down to the landing spot: 42". A sloped yard changes this, so measure where the stairs will land.
- 02
Lay out one stringer
Clamp stair gauges on a framing square at 7" (rise) and 10-1/2" (run). Mark 5 notches along a straight PT 2x12.
- 03
Drop the bottom
Cut 1-1/2 in off the bottom riser so the first step is the same height as the rest once the treads go on.
- 04
Cut and test
Cut the notches with a circular saw, finish the corners with a handsaw, and test the stringer in place before using it as a pattern for the others.
- 05
Install
Fix 4 stringers at no more than 16 in apart with stair connectors, on a solid footing at the bottom.
- 06
Treads
Screw two 2x6 boards to every step, 1/4 in apart, with the front edge overhanging about 3/4 in.
- Every drawing at full page size, dimensions on every member
- The cut list on one page, grouped the way you build
- The cutting diagram for every board
- The materials list ready to hand to the lumberyard or load into a store cart
- The build steps with a check at the end of each
- Your exact size, not the nearest one we had
Before you cut a stringer
What are the code limits for deck stairs?
Under the IRC used by most US towns: risers no taller than 7-3/4 in, treads at least 10 in deep, and every riser in a flight within 3/8 in of the others. Stairs with 4 or more risers need a handrail.
How far apart can stringers be?
At most 16 in on center for composite treads and about 18 in for 2x wood treads. This plan spaces them at 16 in or less.
What is the throat of a stringer?
The solid wood left under the deepest notch. Keep at least 5 in on a 2x12. This plan leaves 5-3/8".
Why cut the bottom of the stringer shorter?
The tread thickness raises every step but the first. Cutting the bottom riser down by one tread thickness keeps all risers equal.