How To Calculate Individual Stair Riser Height For Sloping Steps - Building Code Interpretation
When building stairs, it's crucial to adhere to building codes for safety and compliance. One key aspect is the riser height, which is the vertical distance between each step. This can get tricky when dealing with sloping treads, often used outdoors to allow water runoff.
Understanding the Code
Building codes typically specify a maximum riser height (e.g., 7 3/4 inches). While it might seem straightforward to measure this at the front of the riser, sloping treads require a different approach.
Correct Measurement for Sloping Treads
To accurately measure the riser height on stairs with sloping treads, you need to measure the vertical distance from the front of the lower tread to the front of the upper tread. This ensures you're capturing the true rise despite the tread's angle.
Example
Imagine two stairs:
Stair 1: Level tread with a 7 3/4 inch riser (measured vertically at the front).
Stair 2: Sloping tread. Measuring vertically at the front might show a shorter distance (e.g., 7.5 inches), but measuring from the front of the lower tread to the front of the upper tread reveals the true 7 3/4 inch rise.
Alternative Calculation Method
Another way to determine riser height is to divide the total rise (vertical distance between the upper and lower levels) by the number of risers. This provides an average riser height, which should be within the code-allowed range.
Important Notes
Code Interpretations: Building codes can be complex, and interpretations may vary. Always consult your local building department for clarification.
Inspector's Discretion: The final say on code compliance rests with the building inspector. It's best to discuss any unique situations or interpretations with them beforehand.
Key Takeaways
Accurately measuring riser height on sloping treads is crucial for code compliance.
Measure from the front of the lower tread to the front of the upper tread for the true rise.
Consult your local building department for code clarification and to avoid potential issues.
By understanding these nuances and taking accurate measurements, you can ensure your stairs are safe, functional, and meet all necessary building codes.
