NBC 2025 Stair Dimensions Guide: Treads & Risers | London, Ontario
Sarah's Expert Insight
Senior Consultant at empcontracting.ca Inc.
"In London, Ontario, local building inspectors are strictly enforcing the NBC 2025 uniformity rules to prevent the 'stumble effect' common in older renovations. At empcontracting.ca Inc. your construction contractor in London, Ontario, we utilize precision laser leveling and detailed framing to ensure every step in your home meets these new safety thresholds, protecting your family and your property value."
Understanding the National Building Code of Canada (NBC) 2025 standards for stair design is critical for safety, accessibility, and legal compliance in every construction project. These regulations are designed to minimize fall risks and ensure ergonomic ease of movement.
Riser and Tread Requirements for NBC 2025
Standard Riser Heights
The 2025 NBC specifies that for private stairs within a dwelling unit, the riser height must be between 125 mm (minimum) and 200 mm (maximum). For public or common stairs, the maximum height is capped at 180 mm to facilitate easier access for the general public.
Tread Depth and Run Specifications
Tread depth is the horizontal distance between the front of the nosing and the riser. In the current 2025 standards, private stair runs must typically range from 210 mm to 355 mm. A consistent 'run' is essential for maintaining a rhythmic gait while climbing or descending.
Uniformity and Safety Standards
The Importance of Consistency
One of the most critical aspects of the NBC 2025 is the requirement for uniformity. The code mandates that the difference between the highest and lowest riser, or the deepest and shallowest tread, within a single flight must not exceed 6 mm. Even minor deviations can lead to significant trip hazards.
Nosing and Headroom
Proper nosing projection (typically between 16 mm and 38 mm) is required to provide additional foot space on the tread. Furthermore, a minimum headroom of 2050 mm is generally required above the stairs to ensure safe passage for all users.
Precision Construction with empcontracting.ca Inc.
Designing stairs that meet these rigorous technical requirements requires expert planning. As empcontracting.ca Inc. your construction contractor in London, Ontario, we specialize in translating these complex code requirements into beautiful, functional, and fully compliant staircase installations.