In which situation is roof sheathing NOT required?

Roof sheathing is typically a structural component that provides a surface for roofing materials and adds strength to the roof structure. In certain situations, especially in specific roofing applications, it may not be necessary.

In the case of a wood batten system applied with concrete tiles, the battens can provide adequate support and anchoring for the tiles without the need for sheathing. This system relies on the vertical battens to secure the roofing material and mitigate the forces acting upon it, particularly in high wind areas. Since the concrete tiles are heavy and the battens are secured to the roof frame, they can effectively replace the need for sheathing, allowing for the direct application of roofing materials to the battens.

Other options may indicate situations where structural support or bracing methods could potentially substitute for sheathing, but the use of a wood batten system fundamentally provides the necessary support and stability for concrete tiles without requiring a sheathing layer.