What is the maximum distance a header joist can be located from the trimmed joist bearing?

The maximum distance a header joist can be located from the trimmed joist bearing is four feet. This specification is crucial in roofing and framing to ensure proper load distribution and structural integrity. When header joists are improperly spaced beyond this limit, it can lead to inadequate support for the load above, which increases the risk of sagging or failure under stress.

The four-foot limit is derived from building codes and structural engineering principles that account for factors such as material strength, the type of loads expected, and the possible deflection of joists. This distance provides a balance between structural efficiency and safety, ensuring that the roof system can adequately support not only its own weight but also any additional loads, such as snow or equipment.

The other options suggest shorter or longer distances, which do not align with established construction standards for header joist placement. Therefore, understanding the four-foot maximum distance helps in maintaining compliance with construction codes, ensuring safety and longevity of the roofing structure.