The Ontario Building Code | Thickness, Rating and Material Standards
9.23.16.2. Thickness, Rating and Material Standards
(1) Where wall sheathing is required for the purpose of complying with this Section, it shall conform to Table 9.23.16.2.A. or Table 9.23.16.2.B.
Table 9.23.16.2.A.
wall Sheathing Thickness and Specifications
Forming Part of Sentence 9.23.16.2.(1)
| Item | Column 1 Type of Sheathing | Column 2 Minimum Thickness, mm(1) With supports 406 mm o.c. | Column 3 Minimum Thickness, mm(1) With supports 610 mm o.c. | Column 4 Material Standards |
| 1. | Fibreboard (insulating) | 9.5 | 11.1 | CAN/ulc-S706 |
| 2. | gypsum Sheathing | 9.5 | 12.7 | CAN/CSA-A82.27-M ASTM C1177 / C1177M ASTM C1396 / C1396M |
| 3. | Lumber | 17.0 | 17.0 | See Table 9.3.2.1. |
| 4. | Mineral Fibre, Rigid Board, Type 2 | 25 | 25 | CAN/ulc-S702 |
| 5. | OSB, O-2 Grade | 6.0 | 7.5 | CSA O437.0 |
| 6. | OSB, O-1 Grade, and waferboard, R-1 Grade | 6.35 | 7.9 | CSA O437.0 |
| 7. | Phenolic, faced | 25 | 25 | CAN/cgsb-51.25-M |
| 8. | 6 | 7.5 | CSA O121 CSA O151 CSA O153-M | |
| 9. | Polystyrene, Types 1 and 2 | 38 | 38 | CAN/ulc-S701 |
| 10. | Polystyrene, Types 3 and 4 | 25 | 25 | CAN/ulc-S701 |
| 11. | Polyurethane and Polyisocycanurate Type 1, faced | 38 | 38 | CAN/ulc-S704 |
| 12. | Polyurethane and Polyisocycanurate Types 2 and 3, faced | 25 | 25 | CAN/ulc-S704 |
Notes to Table 9.23.16.2.A.:
(1) See also Sentences 9.27.5.1.(2) to (4).
Table 9.23.16.2.B.
Rating For wall Sheathing When Applying CSA O325
Forming Part of Sentence 9.23.16.2.(1)
| Item | Column 1 Maximum Spacing of supports, mm | Column 2 panel Mark |
| 1. | 406 | W16 |
| 2. | 508 | W20 |
| 3. | 610 | W24 |