Question 3
Domain 2: Building Planning, Means of Egress, and Safety ProvisionsWhat is the minimum headroom clearance required over a stairway per the IRC?
Correct answer: C
Explanation
The IRC requires stairways to have a minimum headroom of "6 feet 8 inches" measured vertically above the stair tread nosings. This clearance ensures safe passage and prevents head strikes while using the stairs.
Why each option is right or wrong
A. 6 feet 4 inches
B. 6 feet 6 inches
C. 6 feet 8 inches
IRC Section R311.7.2 requires stairways to have a minimum headroom of 6 feet 8 inches, measured vertically from the sloped line adjoining the tread nosings. The code applies this clearance throughout the stairway, so any lower obstruction would fail the prescriptive stair geometry requirement.
D. 7 feet