Between the top of the foundation wall and the underside of the floor framing the framer has built a continuous stud wall measuring 5 feet 4 inches in height, and he framed it with the same 2x4 studs at 16 inches on center that he used in the first-floor walls above it. What does the code require of a cripple wall of this height?
- Studs sized for the wall above plus an additional story, so simply matching the 2x4 studs above is not sufficient at this height
- BNothing beyond matching the size of the studs used in the wall above, which is exactly what the framer on this job has already done
Matching the wall above is the intuitive answer and the one the framer acted on. The code treats a cripple wall over 4 feet as another story of framing, so the studs have to be sized for the walls above plus that extra story.
- CStuds one nominal size larger than those used in the wall above, whenever the cripple wall exceeds 2 feet in height
One nominal size larger is a rule of thumb rather than the code's instruction, and the 2-foot trigger is invented. The requirement starts above 4 feet and is stated in stories carried, not as a step up in member size.
- DReplacement with a concrete or masonry wall, because a framed cripple wall is limited to 4 feet in overall height
Framed cripple walls are not capped at 4 feet; above that height they are simply framed as a story of the building. Requiring masonry swaps a framing requirement for a change of material the code never asks for.
Why A is correct
The code sets two rules for cripple walls: never smaller than the studs above, and, above 4 feet in height, sized for an additional story. This wall is 5 feet 4 inches, so the second rule governs and matching the wall above no longer satisfies it.
What this question is testing
Whether the candidate knows the height threshold at which a cripple wall changes from a matching requirement to an additional-story sizing requirement, and whether the candidate treats the cripple wall as a load-carrying story rather than filler framing.
On the job
Sloping lots and daylight basements produce tall cripple walls constantly, and framers build them out of whatever is stacked on site, which is the wall stock for the floors above. The inspector sees it at the foundation or first framing visit, standing in the crawl space with a tape. Tall cripple walls also carry their own bracing requirements, so the visit usually produces two findings rather than one.
Memory technique
Over four feet, count it as a story.
Exam tip
Four feet is the line where a cripple wall stops being trim framing and becomes a story.
Where to look it up
IRC Chapter 6 cripple walls, read together with the stud size, height and spacing table for the number of stories supported.