CSLB General Building (B)Framing and CarpentryHard
A contractor is framing a wall for a new bathroom. The plans indicate that the wall is non-bearing and will contain various plumbing pipes and electrical conduits. What is the maximum percentage of a non-bearing 2x4 stud's width that can be notched, according to typical building codes?
- A15%
- B25%
- C40%
- D33%
Show answer & explanationAnswer & explanation
Correct answer: B. 25%
For non-bearing walls, building codes typically permit notches in 2x4 studs up to a maximum of 25% of the stud's actual width (3.5 inches). This is more restrictive than holes, as notches remove material from one side, significantly impacting the stud's bending strength.
Why the other options are wrong
- A. This is too restrictive; a larger notch is permitted in non-bearing studs.
- C. This percentage is typically for holes in non-bearing studs, not notches, which are more restrictive.
- D. This percentage generally exceeds the allowable notch depth for studs.
Stud Notching Limits (Non-Bearing)
The maximum depth and location of notches permitted in wood studs, particularly for non-bearing walls, to ensure the stud retains sufficient structural capacity.
- Notches are more restrictive than holes due to concentrated stress.
- Limited to 25% of the stud's actual width for non-bearing walls.
- Notches in bearing walls are even more restrictive (e.g., 25% but not in middle third).
Memory trick: Notches are shallow, holes are deep, bearing walls make you weep.