Why is sagging roof sheathing often found on trusses?

Sagging roof sheathing is often observed on trusses primarily due to their spacing. Trusses are engineered components that can be designed to span larger distances than traditional rafters. Because trusses are often placed farther apart, the load they carry can be distributed over a wider area. This wider spacing can lead to insufficient support for the roof sheathing between the trusses, especially if the sheathing itself is not adequately supported or is of a thinner gauge. As a result, the sheathing can sag under the weight of snow, ice, or even the sheathing itself, particularly if there is a lack of proper bracing or if the framing is not sufficiently robust to resist deflection. Understanding the relationship between truss spacing and roof sheathing integrity is critical for identifying potential issues during a home inspection.