NCC stair rules: risers, goings and 2R + G
Common NCC guidance for stairs in houses (Class 1 and 10 buildings): risers 115–190 mm, goings 240–355 mm, and 2R + G between 550 and 700 mm. Risers and goings should be the same all the way up a flight. Always confirm with your certifier.
| Limit | Minimum | Maximum |
|---|---|---|
| Riser (R) | 115 mm | 190 mm |
| Going (G) | 240 mm | 355 mm |
| 2R + G | 550 mm | 700 mm |
Risers for common floor heights
Assumes a preferred riser of about 175 mm and a 250 mm going.
| Floor to floor | Risers | Riser height | Treads | Total going | 2R + G |
|---|---|---|---|---|---|
| 2400 mm | 14 | 171.4 mm | 13 | 3,250 mm | 593 mm |
| 2500 mm | 14 | 178.6 mm | 13 | 3,250 mm | 607 mm |
| 2600 mm | 15 | 173.3 mm | 14 | 3,500 mm | 597 mm |
| 2700 mm | 15 | 180.0 mm | 14 | 3,500 mm | 610 mm |
| 2800 mm | 16 | 175.0 mm | 15 | 3,750 mm | 600 mm |
| 2900 mm | 17 | 170.6 mm | 16 | 4,000 mm | 591 mm |
| 3000 mm | 17 | 176.5 mm | 16 | 4,000 mm | 603 mm |
| 3100 mm | 18 | 172.2 mm | 17 | 4,250 mm | 594 mm |
| 3200 mm | 18 | 177.8 mm | 17 | 4,250 mm | 606 mm |
| 3300 mm | 19 | 173.7 mm | 18 | 4,500 mm | 597 mm |
| 3400 mm | 19 | 178.9 mm | 18 | 4,500 mm | 608 mm |
Estimates only. Check sizes, coverage and quantities with your supplier, engineer or certifier before ordering. Standards references are a guide, not compliance advice.