Roof Sheathing Direction

When you think of using a diagonal brace to support a wall you want to get both ends as far apart as possible.

Roof sheathing direction.

Position the first piece of plywood or oriented strand board sheathing on the bottom edge of the rafter tails at one end of the roof. This opens the door to the possibility of water damage by letting gravity work against you. Wind loads perpendicular to a wall are similar to floor and roof loads and installing sheathing horizontally makes walls better at resisting wind pressure. When the roof sheathing is used as a structural diaphragm as it typically is in high wind and seismic hazard areas the structural integrity of the diaphragm can be compromised by a continuous vent see figure a below left.

When sheathing a roof the first step is to snap a line so that the first row goes on straight. I assume this means the panel should be applied with the long dimension across the studs yet the builder had installed the long dimension parallel to studs. Why is the strength axis important for roof sheathing but not for corner. It spans the rafters to support the roofing and in the case of panel sheathing such as plywood or osb it acts as a diaphragm with the walls to resist horizontal loads.

Properly fasten panels including fastening and spacing hints step 4. Check the nailing surface is level step 2. Maintain ridge nailing by adding additional blocking set back from the ridge or by using vent holes see. But if you snap it at 40 inches then the sheathing will not project over the subfascia or true fascia.

The surface stamp indicated that the strength axis of the panel ran in the long direction see photo below. Cover sheathing with. This solves two points of weakness. On roofs and floors sheathing is installed perpendicular to supports because this is the orientation that results in the strongest roof or floor.

The same policy goes for roof sheathing as for hanging drywall you get more strength by spanning more rafters joists studs and offsetting the joints. Align the long edge of the sheathing with the ends of the. And scroll down to see more details on each with installation hints and tips below. Ventilate the roof according to current building codes step 3.