Residential Building Inspector B1Wall Construction and Wall CoveringsMedium
An inspector is reviewing plans for a residential building utilizing cold-formed steel framing. For non-load-bearing interior walls, what is the minimum base metal thickness for a C-shaped stud with a flange width of 1-5/8 inches and a web depth of 3-5/8 inches?
- A0.043 inch (43 mil)
- B0.027 inch (27 mil)
- C0.018 inch (18 mil)
- D0.033 inch (33 mil)
Show answer & explanationAnswer & explanation
Correct answer: C. 0.018 inch (18 mil)
According to IRC Table R505.2.1(1) for cold-formed steel framing, the minimum base metal thickness for non-load-bearing interior wall studs is 0.018 inch (18 mil), regardless of stud dimensions, as long as it's a C-shaped stud.
Why the other options are wrong
- A. 0.043 inch is a heavy gauge and would be used in highly specialized or high-load applications, far exceeding minimum non-load-bearing requirements.
- B. 0.027 inch is a common thickness for load-bearing applications or specific structural requirements, not the minimum for non-load-bearing.
- D. 0.033 inch is significantly thicker and typically used for more demanding load-bearing scenarios.
Cold-Formed Steel Stud Thickness
The minimum base metal thickness for cold-formed steel studs varies based on whether the wall is load-bearing or non-load-bearing.
- Non-load-bearing interior walls: 0.018 inch (18 mil).
- Load-bearing walls require thicker gauges, typically 0.033 inch (33 mil) or more.
- Thickness is measured in inches or mils (1 mil = 0.001 inch).
Memory trick: Steel studs need the right gauge, light for non-load, heavy for load.