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Sheathing: thickness and nailing info

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Here are the requirements for sheathing thickness and nailing (plus patterns) for wall and roof sheathing.

Note that requirements for earthquake panels in NBC 2015 are more restrictive. Contact your building inspector for details.

Required thickness of wall sheathing

40 cm (16") OC 60 cm (24") OC
Fibreboard (insulated) 9.5 mm  (3/8") 11.1 mm  (13/16")
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 cm (11/16")
400 mm (16") 7.5 mm (1/4") 9.5 mm  (3/8") 9.5 mm  (3/8") 11.1 mm  (13/16") 17 cm (11/16")
600 mm (24") 9.5 mm  (3/8") 12.5 mm (31/64") 11.1 mm  (13/16") 12.7 (1/2") 17 cm (11/16")

 

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")

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