Residential Building Inspector B1Public Safety and Special ConstructionMedium
An inspector is evaluating a stairway for a residential dwelling. The stairway consists of three risers and four treads. What is the minimum required headroom clearance above the stair treads?
- A7 feet 6 inches (2286 mm)
- B6 feet 4 inches (1930 mm)
- C7 feet 0 inches (2134 mm)
- D6 feet 8 inches (2032 mm)
Show answer & explanationAnswer & explanation
Correct answer: D. 6 feet 8 inches (2032 mm)
The IRC specifies a minimum headroom clearance of 6 feet 8 inches (2032 mm) at all points above the finished floor or tread surface, measured vertically from the most projected nosing of the tread below. This ensures safe passage without occupants striking their heads.
Why the other options are wrong
- A. This exceeds the minimum required headroom clearance and is not specified by the code.
- B. This is less than the minimum required headroom clearance for stairs.
- C. This is the minimum ceiling height for habitable spaces, not specifically for stairways.
Stair Headroom Clearance
The minimum vertical distance required above the tread nosing or finished floor for safe passage on a stairway.
- Minimum 6 feet 8 inches (2032 mm)
- Measured vertically from tread nosing or finished floor
- Applies to all points above the stairway
Memory trick: Headroom is key for a clear ascent.