OBC SB-7 reference
Span Tables
Quick-reference spans for the most common framing members in Ontario homes.
Floor Joists
Solid-sawn lumber floor joists supporting residential live load (1.9 kPa / 40 psf), L/360 deflection.
OBC SB-7 Table A-1 (Floor joists, residential)
Max clear span — SPF No. 1/2, 1.9 kPa live load, L/360
| Joist size | 12" o.c. | 16" o.c. | 19.2" o.c. | 24" o.c. |
|---|---|---|---|---|
| 2x6 | 3.16 m (10'-4") | 2.87 m (9'-5") | 2.70 m (8'-10") | 2.51 m (8'-3") |
| 2x8 | 4.17 m (13'-8") | 3.79 m (12'-5") | 3.56 m (11'-8") | 3.31 m (10'-10") |
| 2x10 | 5.32 m (17'-5") | 4.83 m (15'-10") | 4.55 m (14'-11") | 4.22 m (13'-10") |
| 2x12 | 6.47 m (21'-3") | 5.88 m (19'-3") | 5.53 m (18'-2") | 5.14 m (16'-10") |
Excerpt — verify against the official OBC SB-7 Table A-1.
Notches & holes in solid lumber joists
| Item | Limit |
|---|---|
| Hole max diameter | 1/4 of joist depth |
| Hole edge distance | ≥ 50 mm from top/bottom |
| Notch depth (top/bottom) | 1/3 of depth, only in outer thirds of span |
| End notch | 1/4 of depth max |
Source: OBC 9.23.5.2
Tables are summary excerpts — always confirm against the official OBC SB-7 and a qualified designer or engineer for your project.