What is the typical spacing range for rafters in a roof structure?

The typical spacing range for rafters in a roof structure is indeed 12 to 24 inches. This spacing is commonly used to provide adequate support for the roofing materials, maintain structural integrity, and distribute loads evenly across the structure. It allows for proper attachment of the roof covering and provides sufficient space for insulation installation, ventilation, and potential access for maintenance.

Choosing a spacing of 12 to 24 inches strikes a balance between structural efficiency and cost considerations. Closer spacing increases the roof's strength and could handle more weight or live loads, while wider spacing may reduce material costs and provide more room for insulation but might compromise the roof’s overall strength.

In practice, the specific spacing used can also depend on various factors, including local building codes, the type of roofing materials used, and design requirements specific to the building's characteristics. Building codes often dictate the maximum allowable spacing based on these factors to ensure safety and performance.