North Carolina Building Contractor License Practice Exam

What is the maximum allowable notch depth on the ends of joists relative to the joist depth?

1. 1/3

2. 1/2

3. 2/3

4. 3/4

The correct answer is: 1/3

The maximum allowable notch depth on the ends of joists is limited to one-third of the joist depth to ensure structural integrity and safety. Notching deeper than this can compromise the strength of the joists, as it removes a significant portion of the material that contributes to its ability to support loads. The limitation to one-third helps distribute the stresses and allows the joist to maintain its load-bearing capacity. For example, if you have a joist with a depth of 12 inches, the maximum notch allowed would be 4 inches (which is one-third of 12 inches). This rule is part of established building codes and standards to prevent failures that can arise from excessive notching, ensuring that the joists can adequately support the intended loads without risking structural failure.