CSLB General Building (B)Framing and CarpentryHard
A building inspector measures the headroom in a straight residential stairway as 79 inches, taken vertically from a line connecting the nosings of the treads to the ceiling above. Does this stairway comply with the California Residential Code minimum headroom requirement?
- AYes, because headroom requirements only apply to spiral staircases
- BYes, because the minimum required headroom is 78 inches
- CNo, because the minimum required headroom is 80 inches and 79 inches falls short
- DNo, because headroom must be measured from the finished floor, not the nosing line
Show answer & explanationAnswer & explanation
Correct answer: C. No, because the minimum required headroom is 80 inches and 79 inches falls short
The CRC requires a minimum headroom clearance of 6 feet 8 inches (80 inches) for stairways, measured vertically from a line connecting the tread nosings to the ceiling or any overhead obstruction. A measured headroom of 79 inches is 1 inch short of this requirement and would not comply (the 78-inch exception applies only to spiral stairways).
Why the other options are wrong
- A. Headroom requirements apply to all stairway types, with spiral stairs having a separate, lower minimum.
- B. 78 inches is the reduced allowance for spiral stairways only, not standard straight stairs.
- D. The code correctly measures headroom from the nosing line, which is the method used here; the failure is the height, not the measurement point.
Stairway Headroom Minimum
The California Residential Code requires a minimum vertical headroom clearance of 80 inches (6'8") for stairways, measured from the nosing line to any overhead obstruction.
- Standard minimum: 80 inches
- Spiral stair exception: 78 inches
- Measured from a line through the tread nosings
Memory trick: Six-eight is the height, or your head takes a hit.