What is the primary function of sheathing in roofing?

The primary function of sheathing in roofing is to provide a structural layer that supports the roof rafters. Sheathing, typically made from materials like plywood or oriented strand board (OSB), creates a solid base for other roofing components to be installed, such as shingles or tiles. It helps to distribute the weight of the roof and adds structural integrity, which is essential for the overall stability of the roofing system. Properly installed sheathing also helps with the alignment of roofing materials, ensuring they fit well and are secure.

While sheathing does play a role in other areas—such as providing some degree of insulation by reducing airflow, helping to hold roofing tiles in place as a substrate, and serving as a base for decorative roofing materials—its fundamental purpose is to act as a support structure for the roof framework. This structural function is crucial for maintaining the roof's overall performance and durability over time.