The Ontario Building Code (OBC) has specific requirements for stair width and handrails in houses (inside a home or additional residential unit). Following these rules helps to ensure that stairs are safe and comfortable for everyone to use. Always check your measurements when building or renovating stairs. Refer to Ontario Building Code articles 9.8.2.1, 9.8.6.2, 9.8.7.5 and 9.8.7.6 for prescribed requirements.
Minimum Stair Width
- All stairs and landings must be at least 860 millimetres wide (about 34 inches).
- This measurement is taken from finished wall to finished wall, or from finished wall to inside surface of guard.
Handrail Rules
- Handrails require proper space between back of handrail and the wall or surface behind. Depending on the surface material, this space may be different:
- If the surface is rough or abrasive: 60 millimetres (about 2.4 inches).
- Other (smooth) surfaces: 50 millimetres (about 2 inches).
- Handrails and their supports may project up to 100 millimetres (about 3.9 inches) into the required stair width.
Quick Reference Chart
| Requirement | Minimum Standard |
|---|---|
| Stair & Landing Width | 860 mm (34 in.) |
| Handrail/Projection Intrusion | 100 mm (4 in.) max |
| Handrail Clearance (rough surface) | 60 mm (2.4 in.) |
| Handrail Clearance (other surfaces) | 50 mm (2 in.) |
For additional information, please refer to our Residential (Part 9) Stairs & Handrails Building Services Information Sheet.
Paul Evans, CBCO, MAATO
Chief Building Official
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