Residential Building Inspector B1Building Planning and Life SafetyMedium
A residential building inspector is reviewing plans for a new single-family dwelling. The plans include a stairway with a closed riser design. What is the maximum riser height permitted for this stairway?
- A8 1/4 inches (210 mm)
- B8 inches (203 mm)
- C7 inches (178 mm)
- D7 3/4 inches (197 mm)
Show answer & explanationAnswer & explanation
Correct answer: D. 7 3/4 inches (197 mm)
Stairways must conform to specific dimensions for safety and ease of use. The maximum riser height is a critical dimension to prevent trips and falls.
Why the other options are wrong
- A. This exceeds the maximum allowable riser height.
- B. This exceeds the maximum allowable riser height.
- C. This is a common maximum riser height in some commercial or public buildings, but not the IRC residential maximum.
Stairway Riser Height
The vertical measurement from the top of one tread to the top of the next tread in a stairway, with a maximum limit for safety.
- Critical for preventing trips and falls.
- Must be uniform within a flight of stairs.
- Paired with minimum tread depth requirements.
Memory trick: Riser's height, seven and three-quarters, keeps your steps just right.