Roof Sheathing Should Be Installed

Sheathing is installed perpendicular to roof trusses.

Roof sheathing should be installed.

Local roof repair contractors inspect the sheathing during maintenance repairs and especially during roof replacement. The first thing we check is the thickness of the material used. 8d ring shank nails should be used instead. In areas where the wind speed is greater than 130 mph nails for attaching the roof sheathing to intermediate supports should be spaced 6 inches on center for at least the first 48 inches from the ridges eaves and gable end walls.

Sheathing should be a minimum of 19 32 inch thick. For plywood composite or osb boards installed on rafters it should be at least 5 8ths of an inch thick. In this case to keep the panel s strength axis perpendicular to the hip trusses the panels on the hip roof portion must be installed with their long dimension oriented up and down the slope. Never attach roof sheathing with staples.

Tongue and groove installations require thicker material at least 1 1 2 inches thick as they don t often require insulation and often double as the ceiling. 24 inches on center the actual distance between panel supports measured along the slope is greater than the truss spacing. There should be at least 3 8 inch of space between the fastener and the panel edge. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame.

Trusses or rafters should be shimmed as necessary to provide a level nailing surface. Slide the sheet one rafter width over the end of the roof so the edge is centered on the next rafter offset one rafter spacing from the first piece of installed sheathing from the row below. If the top chords of trusses or rafters are warped or bowed install blocking to straighten.