Laundry room partition with door opening
What's wrong here?
- Table R602.7.5 requires two full-height king studs at each side of this opening
- Every stud wall must be capped with a double top plate
- A single flat 2x4 may not be used as a header over a door opening
- Nothing. This installation is compliant
Show the answer and the code reference
The answer
Nothing is wrong: this is an interior nonbearing partition, so a single flat 2x4 header and a single top plate are both permitted.
Correct choice: 4. Nothing. This installation is compliant
The floor joist above runs parallel to the partition, so no joists, rafters or trusses bear on it; the wall only holds up itself and the drywall. R602.7.4 says load-bearing headers are not required in nonbearing walls and allows a single flat 2x4 header for openings up to 8 ft wide where the vertical distance to the parallel nailing surface above is no more than 24 in., which is easily met here. R602.5 lets interior nonbearing walls be capped with a single top plate (and even framed with 2x3 studs at 24 in. on center). The bottom plate on the basement slab is preservative-treated, the usual way to meet R317.1 for a plate resting on a slab.
How to fix it
No correction needed. Before calling it nonbearing on a real job, confirm what is above: joists running parallel to the wall, or trusses designed to clear-span, with no point loads or posts landing on the plate.
Code references
IRC 2018 R602.7.4 — Nonbearing walls
Load-bearing headers are not required in interior or exterior nonbearing walls. A single flat 2x4 may be used as a header in a nonbearing wall for openings up to 8 ft wide if the vertical distance to the parallel nailing surface above is not more than 24 in.; no cripples or blocking are required above it.
Drills citing R602.7.4IRC 2018 R602.5 — Interior nonbearing walls
Interior nonbearing walls may be framed with 2x3 studs at 24 in. on center (or flat 2x4s at 16 in. where not part of a braced wall line) and must be capped with not less than a single top plate; they must be fireblocked per R602.8.
Drills citing R602.5
2024 IRC:not yet checked Confidence: low
Minnesota
No Minnesota amendment to R602.7.4 or R602.5 is known. DLI is adopting the 2024 IRC as the next edition; see the 2024 IRC note.
About the Minnesota Residential CodeWhy the other choices are wrong
- Table R602.7.5 requires two full-height king studs at each side of this opening. Table R602.7.5 sets the number of full-height studs at the ends of headers in exterior walls. This is an interior nonbearing partition, and one king stud each side is normal.
- Every stud wall must be capped with a double top plate. R602.3.2's double top plate applies to exterior walls and, through R602.4, to interior bearing walls. R602.5 lets interior nonbearing walls be capped with a single top plate.
- A single flat 2x4 may not be used as a header over a door opening. R602.7.4 allows a single flat 2x4 header in a nonbearing wall for openings up to 8 ft wide when the nailing surface above is no more than 24 in. away. The joist above runs parallel to this partition, so nothing bears on it.