Question 11
Domain 2: Building Planning, Means of Egress, and Safety ProvisionsWhat is the minimum required size of a residential bathroom per the IRC?
Correct answer: B
Explanation
The IRC does not set a minimum floor area for a residential bathroom. Instead, it requires fixture spacing and clearances, so the room may be any size as long as the toilet, lavatory, and bathing fixtures meet the code’s required clearances.
Why each option is right or wrong
A. 35 square feet
B. There is no minimum room size, but fixtures must have specific clearances
The IRC does not prescribe a minimum square footage for a residential bathroom; instead, it regulates fixture placement and clearances. Under IRC P2705.1 and P2705.1.1, the toilet, lavatory, and bathing fixture must be arranged so the required clearances are maintained, including at least 21 inches in front of a water closet, lavatory, or bidet and 24 inches in front of a shower or tub opening, with a minimum 15-inch centerline clearance from the water closet to any side wall or obstruction.
C. 50 square feet
D. 70 square feet