| Primary value | 0.90 m |
| Applies to | Single-family houses · Internal stairs in independent dwellings |
| Exceptions | Apartments / group housing → 1.25 m |
| Group housing > 24 m height → 1.50 m | |
| Measured as | Clear width between handrail / wall faces, excluding any projecting balusters. |
| Source | NBC 2016 — Part 4, Clause 4.4.1 ✓ Verified |
0.90 m is wide enough for one person to climb comfortably and for furniture to be moved up by tilting and angling. Below this, even modest pieces of furniture can't be hauled to upper floors.
Most individual homes provide 0.95–1.10 m for comfortable use and furniture moving. Below 0.9 m feels cramped even for daily use.