Under the new family room ceiling the clear height is 7 feet, except beneath one girder, well isolated from any other beam, where the clear height drops to 6 feet 6 inches. The finished bathroom measures 6 feet 10 inches from floor to ceiling. What should the inspector cite?
- AThe girder only, because any projection that brings the clear height below 7 feet is a violation
Isolated beams and girders are expressly allowed to project up to 6 inches below the required ceiling height, so the girder at 6 feet 6 inches is not a violation.
- BBoth the girder and the bathroom, because 7 feet is an absolute minimum at every point in the space
Seven feet is not absolute. The beam and girder allowance is written into the section itself.
- The bathroom only, because it falls below 7 feet while an isolated girder is allowed to project up to 6 inches
- DNothing, because a basement is held to a 6-foot 8-inch ceiling height throughout
The 6-foot 8-inch height applies to basements without habitable space. A basement containing a family room and a bathroom does not qualify for it.
Why C is correct
Seven feet is the required ceiling height for habitable space and also for bathrooms, toilet rooms, laundry rooms and hallways. An isolated beam or girder may project up to 6 inches below that height, so 6 feet 6 inches under a single girder is inside the exception. The bathroom is a full room at 6 feet 10 inches, which is below the requirement and is not a projection, so it is the defect the inspector cites.
What this question is testing
The item tests whether the candidate can apply the ceiling height requirement to the rooms it actually covers, recognize the beam and girder allowance, and reject the reduced basement height where habitable space is present.
On the job
Basement finishes live and die on ceiling height, because the joists, the ductwork and the girder are all fixed before anyone thinks about finishing. Owners routinely learn at the framing inspection that the bathroom they framed under the lowest duct run cannot be permitted. The productive conversation happens before the layout is set: identify the low areas, put the storage and mechanical spaces under them, and keep the habitable rooms and the bathroom under the clear bays.
Memory technique
Seven feet everywhere people go, minus six inches for a beam you can walk around.
Exam tip
Bathrooms, laundry rooms and hallways get the same 7 feet as habitable rooms. Only isolated beams get the 6-inch break.
Where to look it up
IRC Chapter 3, Section R305.1 and its exceptions for beams, girders and basements.