Step 1 of the upper flight has only 894 mm of headroom under the ceiling — below the 2000 mm required (short by 1106 mm). Extend the opening toward the landing by at least 300 mm, or move it the same amount, so it starts before this step.
Stair pitch of 25.53° is outside the commonly comfortable range of 30°-45°. This is a general rule of thumb, not a specific building code requirement — comfortable ranges vary by country.
2 × riser height + going is 698 mm, outside the comfortable range of 630 mm ± 30 mm (the historical "Blondel formula"). This is a general rule of thumb, not a specific building code requirement.
Diagram
Plan view
Side elevation, lower flight
Side elevation, upper flight
Step setting-out
Riser height171mm
Tread depth382mm
Dimensions
MRiser height171 mm
NGoing357 mm
OPitch angle25.5°
TTread depth382 mm
PLower flight run2,857 mm
QUpper flight run2,500 mm
VLanding height (above base floor)1,535 mm
RLower flight stringer length3,244 mm
SUpper flight stringer length2,848 mm
Risers, lower flight9
Risers, upper flight8
Headroom
UMinimum headroom clearance894 mm
Occurs at step1
Opening would need to start at (from landing)0 mm
Opening would need to be at least2,500 mm
Materials
Stringer timber required (all 4)12.183 m
Total tread area5.16 m²
Tread timber volume165.02 L
Stringer timber volume132.42 L
Tread timber, linear length13.500 m
Tread boards to buy3
Riser timber, linear length13.500 m
Riser boards to buy3
Stringer timber, linear length12.183 m
Stringer boards to buy3
Parts list
| Count | Length | Width | Thickness | |
|---|---|---|---|---|
| Tread | 15 | 900 mm | 382 mm | 32 mm |
| Riser | 15 | 900 mm | 139 mm | 19 mm |
| Stringer, lower flight | 2 | 3,244 mm | 286 mm | 38 mm |
| Stringer, upper flight | 2 | 2,848 mm | 286 mm | 38 mm |
TreadCount: 15
- Length
- 900 mm
- Width
- 382 mm
- Thickness
- 32 mm
RiserCount: 15
- Length
- 900 mm
- Width
- 139 mm
- Thickness
- 19 mm
Stringer, lower flightCount: 2
- Length
- 3,244 mm
- Width
- 286 mm
- Thickness
- 38 mm
Stringer, upper flightCount: 2
- Length
- 2,848 mm
- Width
- 286 mm
- Thickness
- 38 mm