Stairs by floor height · 8 ft 6 in · L-shaped, winders
L-shaped stairs with winders for an 8 ft 6 in floor height
15 risers of 6 13/16″ and 14 treads 11″ deep, at 32°. 36″ wide, it takes 8′ 6 1/8″ × 7′ 7 1/8″ of floor. Three winders carry it round the corner, each taking a riser, so it needs no landing.
Open this stair in uCADWhat it’s made of
More or fewer steps
8 ft 6 in (102″) can be climbed in fewer, higher steps or more, lower ones. Each opens in uCAD as this stair with that many risers.
| Risers | Each riser | Going | Pitch | Run of a straight flight | How it walks | In uCAD |
|---|---|---|---|---|---|---|
| 13 | 7 7/8″ | 9 13/16″ | 39° | 9′ 10 1/8″ | over the IRC’s 7¾″ riser | open |
| 14 | 7 5/16″ | 10 1/4″ | 35° | 11′ 1 1/16″ | steeper, fewer steps | open |
| 15 | 6 13/16″ | 11″ | 32° | 12′ 10 5/16″ | comfortable (drawn here) | open |
| 16 | 6 3/8″ | 12 3/16″ | 28° | 15′ 3 1/16″ | comfortable | open |
The IRC (US homes) allows risers up to 7¾″ and asks for treads of at least 10″, 6′8″ of headroom and a width of 36″; states and towns amend it. Check the code that applies to yours.
What it’s made of
Drawn as it’s built, in timber with open treads: treads housed in the stringers, posts under the turns, a railing on its newels. 213 parts in all, every bolt and weld among them. Sizes in inches, length × width × thickness.
| Part | Qty | Length | Width | Thickness |
|---|---|---|---|---|
| stringer (shaped) | 1 | 121 11/16″ | 15 3/4″ | 1 15/16″ |
| stringer (shaped) | 1 | 107 3/8″ | 15 11/16″ | 1 15/16″ |
| tread (shaped) | 1 | 42 3/8″ | 21 1/16″ | 1 9/16″ |
| tread (shaped) | 1 | 48 5/16″ | 18 7/16″ | 1 9/16″ |
| tread (shaped) | 1 | 43″ | 20 5/8″ | 1 9/16″ |
| stringer (shaped) | 1 | 77 5/8″ | 10 3/8″ | 1 15/16″ |
| stringer (shaped) | 1 | 64 3/16″ | 10 3/8″ | 1 15/16″ |
| tread | 11 | 37 3/16″ | 12″ | 1 9/16″ |
| post, timber 90x90 | 1 | 100 3/16″ | 3 9/16″ | 3 9/16″ |
| post, timber 90x90 | 1 | 60 7/16″ | 3 9/16″ | 3 9/16″ |
| post, timber 90x90 | 1 | 53 7/8″ | 3 9/16″ | 3 9/16″ |
| post, timber 90x90 | 1 | 46 3/4″ | 3 9/16″ | 3 9/16″ |
| handrail, round 50 mm (shaped) | 1 | 73 1/8″ | 1 15/16″ | 1 15/16″ |
| handrail, round 50 mm (shaped) | 1 | 60 3/16″ | 1 15/16″ | 1 15/16″ |
| baluster, steel square bar 18 mm (shaped) | 21 | 33 5/16″ | 11/16″ | 11/16″ |
Fixings: 3 × tie rod M10x1041, 44 × washer M10, 32 × nut M10, 21 × stud M8x80, glued, 21 × screw 5x45, 3 × bracket, concealed post base 90, 8 × anchor bolt M10x100, 6 × stud M10x117, 2 × anchor bolt M10x200, 2 × bracket, steel angle 100x100x8, 2 × stud M10x85, 12 × bolt M10x170, 12 × nut M10, barrel.
Closed risers, a steel frame, another width or railing: change it in uCAD, and the parts are worked out again, with a cut list of the boards to buy. Sizes of the structure are the library’s defaults for a house stair, not an engineer’s calculation for yours.
Another height or width

Will it fit your room?
Open it in uCAD, draw your walls round it and look: turn it the other way, move the turn up or down, change the width. Or tell the AI: “a stair for 8 ft 6 in in a 7 × 10 ft stairwell”, and it draws one that fits.
Same height: Straight · L-shaped, landing · U-shaped, landing · U-shaped, winders · Spiral · Square spiral
This stair for 8 ft 3 in · 8 ft 9 in · all heights