How should roof sheathing be installed in relation to the rafters?

Installing roof sheathing in a perpendicular orientation to the rafters provides several structural advantages. This method enhances the strength and stability of the roof system by allowing the sheathing to distribute loads more evenly across the rafters. When the sheathing is perpendicular, each panel contributes to the overall rigidity of the roof, reducing the potential for sagging or movement over time.

Additionally, a perpendicular installation helps prevent issues such as wind uplift, as the panels interlock with the rafters more effectively, ensuring that the roof remains securely attached even under challenging weather conditions. This orientation also allows for better alignment with the seams, providing a continuous deck that minimizes the risk of leakage where the panels meet.

Choosing to install sheathing in other orientations, such as diagonal or parallel to the rafters, does not offer the same level of support and can lead to weaknesses in the roof structure. This could result in difficulties with wind resistance, potential buckling, or inadequate load distribution, which are critical factors in maintaining a durable roofing system.