When notching exterior load-bearing walls, why is there a maximum percentage specified?

Notching exterior load-bearing walls has a specified maximum percentage to maintain structural integrity. Load-bearing walls are crucial as they support the weight of the structure above them, including roofs and additional floors. When notches are created, they alter the distribution of weight and may weaken the wall if not done correctly. By limiting the maximum percentage of the wall that can be notched, builders ensure that the wall retains sufficient strength and can properly bear the loads it is designed to support. This practice is essential for preventing structural failure such as sagging or collapse, which could occur if the wall's capacity to bear weight is compromised.

While compliance with local codes and preventing moisture accumulation are also important aspects in construction, the primary reason for restricting notching relates directly to the preservation of the wall's load-bearing function. Aesthetic purposes are not a consideration when discussing the structural requirements of load-bearing walls, making maintaining structural integrity the key focus.