What is the maximum allowable width for notching in a solid sawn beam?

The maximum allowable width for notching in a solid sawn beam is one-third of the beam depth. This guideline is established to ensure the structural integrity and load-bearing capacity of the beam. Notching, while sometimes necessary for passing plumbing, electrical, or HVAC systems through beams, can weaken the beam if done excessively or improperly.

Allowing a notch that is too wide can lead to a significant reduction in the beam’s strength and stability. By restricting the notch width to one-third of the beam depth, this guideline helps maintain a sufficient cross-sectional area of the beam to resist bending and shear forces effectively.

In contrast, notches that exceed this dimension could potentially compromise the performance of the beam under load, leading to structural issues such as bending or even failure. This is why the other options, which allow for notches greater than one-third of the beam depth, would not comply with the best practices in structural design and safety standards.