Sheathing: Thickness and Nailing Information
Here are the requirements for sheathing thickness and nailing (plus patterns) for wall and roof sheathing.
Required thickness of wall sheathing
| 40 cm (16″) OC | 60 cm (24″) OC | |
| Fibreboard (insulated) | 9.5 mm (3/8″) | 11.1 mm (7/16″) |
| Gypsum sheathing | 9.5 mm (3/8″) | 12.7 (1/2″) |
| Lumber | 17 cm (11/16″) | 17 cm (11/16″) |
| Rigid mineral board | 25 mm (1″) | 25 mm (1″) |
| OSB O-2 | 6 mm (15/64″) | 7.5 mm (1/4″) |
| OSB O-1 | 6.35 (1/4) | 7.9 mm (5/16″) |
| Waferboard, R-1 | 25 mm (1″) | 25 mm (1″) |
| Phenolic, faced | 25 mm (1″) | 25 mm (1″) |
| Plywood (exterior) | 6 mm (15/64″) | 7.5 mm (1/4″) |
| Polystyrene 1 &2 | 38 mm (1.5″) | 38 mm (1.5″) |
| Polystyrene 3&4 | 25 mm (1″) | 25 mm (1″) |
| Polyurethane, Polyiso Type 1 | 38 mm (1.5″) | 38 mm (1.5″) |
| Polyurethane, Polyiso Type 2 & 3 | 25 mm (1″) | 25 mm (1″) |
Thickness of roof sheathing
| Truss/rafter spacing | Plywood and OSB O-2 grade | OSB, 0-1 grade, Waferboard, R-1 grade | board lumber | ||
| Edge supported | Edges unsupported | Edge supported | Edges unsupported | ||
| 300 mm (12″) | 7.5 mm (1/4″) | 7.5 mm (1/4″) | 9.5 mm (3/8″) | 9.5 mm (3/8″) | 17 mm (11/16″) |
| 400 mm (16″) | 7.5 mm (1/4″) | 9.5 mm (3/8″) | 9.5 mm (3/8″) | 11.1 mm (7/16″) | 17 mm (11/16″) |
| 600 mm (24″) | 9.5 mm (3/8″) | 12.5 mm (31/64″) | 11.1 mm (7/16″) | 12.7 mm (1/2″) | 17 mm (11/16″) |
Note that requirements for earthquake panels in NBC 2015 are slightly more restrictive: In general, the requirement is for 2 1/2″ nails (no, the standard 2 3/8″ nail will NOT do) OR 2″ screws at a standard spacing – 6″ on edges, 12″ on intermediate supports (if required.)
Required fasteners for sheathing
| Element | Common/spiral nails | Ring nails/screws | Roofing nails | staples | Spacing |
| Board lumber 184 mm (7 1/4″) | 51 mm (2″) | 45 mm (1 3/4″) | x | 51 mm (2″) | 2 per support |
| Board lumber > 184 mm (7 1/4″) | 51 mm (2″) | 45 mm (1 3/4″) | x | 51 mm (2″) | 3 per support |
| Fibreboard sheathing <= 13 mm (1/2″) thick | x | x | 44 mm (1 3/4″) | 28 mm (1 1/8″) | 15 cm on edge, 30 cm middle (6 & 12″) |
| Gypsum sheathing up to 13 mm (1/2″) thick | x | x | 44 mm (1 3/4″) | X | 15 cm on edge, 30 cm middle (6 & 12″) |
| Plywood/OSB/waferboard to 10 mm (3/8″) thick | 51 mm (2″) | 45 mm (1 3/4″) | x | 38 mm (1 1/2″) | 15 cm on edge, 30 cm middle (6 & 12″) |
| Plywood/OSB/waferboard 10 mm (3/8″) to 20 mm (13/16″) thick | 51 mm (2″) | 45 mm (1 3/4″) | X | 51 mm (2″) | 15 cm on edge, 30 cm middle (6 & 12″) |
| Plywood/OSB/waferboard more than 20 mm (13/16″) thick | 57 mm (2 1/4″) | 51 mm (2″) | x | x | 15 cm on edge, 30 cm middle (6 & 12″) |