How is rafter spacing typically determined in roofing?

Rafter spacing is typically determined by local building codes and structural requirements because these regulations ensure that the roof can support the necessary loads, including live loads (like snow and people) and dead loads (the weight of the roofing materials themselves). Building codes are designed to promote safety, stability, and durability in construction, and they provide specific guidelines for spacing that must be followed to comply with safety standards.

While factors such as the slope of the roof and the type of roofing materials can influence the overall design and construction process, they do not override the importance of adhering to local codes. Building codes take into account various considerations including wind loads, seismic activity, and the specific materials used in construction. These codes are developed based on extensive research and engineering principles to ensure a safe and effective structural system.

Personal preference of the builder does not reliably reflect the necessity for structural integrity, which is why it is not a valid approach for determining rafter spacing in roofing.