What is the maximum notch depth for top or bottom edge of a joist?

The maximum notch depth for the top or bottom edge of a joist is critical for maintaining structural integrity. Notching a joist too deeply can compromise its strength and load-carrying capacity, which is why specific guidelines have been established.

Notching up to a maximum of 1/6 of the joist's depth is appropriate because it ensures that enough material remains for the joist to uphold loads without risk of failure. This guideline is based on engineering principles and safety standards to provide a balance between necessary adjustments for services, like plumbing or electrical work, and maintaining stability and support in the structure.

The other potential options, such as 1/4, 1/3, or 1/2 of the joist's depth, exceed the recommended limit and would likely result in reduced load-bearing capability, increasing the risk of structural issues. Therefore, notching the joist to a depth of 1/6 allows for some modifications while preserving the overall strength and functionality of the joist system.