NBC 2025 Stair Tread and Riser Dimensions: Expert Guide for London, Ontario Construction
Sarah's Expert Insight
Senior Consultant at empcontracting.ca Inc.
"In London, Ontario, municipal inspectors are particularly focused on stair uniformity during framing inspections to reduce long-term liability for property owners. At empcontracting.ca Inc., we advise our clients that investing in precise stair geometry not only ensures NBC 2025 compliance but significantly enhances the daily comfort and safety of their home or business."
Understanding NBC 2025 Staircase Safety Standards
Compliance with the National Building Code (NBC) 2025 is essential for any residential or commercial project. As empcontracting.ca Inc. your construction contractor in London, Ontario, we ensure that every staircase is engineered for maximum safety and ergonomic comfort. The 2025 updates continue to emphasize the importance of consistent tread and riser dimensions to prevent fall-related injuries.
Key Dimensions for Private Dwelling Stairs
For private stairs within a single dwelling unit, the NBC 2025 specifies the following requirements to ensure a safe gait:
- Riser Height: Minimum 125 mm to a maximum of 200 mm.
- Tread Depth: Minimum 255 mm (measured from the face of one riser to the face of the next).
- Stair Run: Minimum 210 mm to a maximum of 355 mm.
- Nosing Projection: Maximum 25 mm.
The Critical Rule of Uniformity
Perhaps the most vital aspect of the NBC 2025 is the strict requirement for uniformity. Any significant variation in step height or depth can cause a person to trip. The code permits a maximum tolerance of only 5 mm between adjacent treads or risers, and no more than 10 mm between the largest and smallest dimensions in an entire flight. At empcontracting.ca Inc. your construction contractor in London, Ontario, we utilize precision digital measuring tools to guarantee this level of accuracy.
Public and High-Traffic Stairway Specifications
For public stairs, the requirements are even more stringent to accommodate diverse user needs. Public risers must be between 125 mm and 180 mm, while the minimum tread depth is increased to 280 mm. This shallower, deeper step configuration facilitates safer movement for individuals with varying mobility levels and reduces the risk of accidents in high-density environments.