// CODE SNIPPET
2308.7 Roof and Ceiling Framing
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The framing details required in this section apply to roofs having a slope of not less than three units vertical in 12 units horizontal (25-percent slope). Where the roof slope is less than three units vertical in 12 units horizontal (25-percent slope), members supporting rafters and ceiling joists such as ridge board, hips and valleys shall be designed as beams.
Spans for ceiling joists shall be in accordance with Table 2308.7.1(1) or 2308.7.1(2). For other grades and species, and other loading conditions, refer to the AWC STJR.
CEILING JOIST SPANS FOR COMMON LUMBER SPECIES (Uninhabitable attics without storage, live load = 10 psf, L/Δ = 240)
| CEILING JOIST SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 5 psf | ||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | |||
| Maximum ceiling joist spans | ||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 12 | Douglas Fir-Larch | SS | 13-2 | 20-8 | Note a | Note a |
| Douglas Fir-Larch | #1 | 12-8 | 19-11 | Note a | Note a | |
| Douglas Fir-Larch | #2 | 12-5 | 19-6 | 25-8 | Note a | |
| Douglas Fir-Larch | #3 | 10-10 | 15-10 | 20-1 | 24-6 | |
| Hem-Fir | SS | 12-5 | 19-6 | 25-8 | Note a | |
| Hem-Fir | #1 | 12-2 | 19-1 | 25-2 | Note a | |
| Hem-Fir | #2 | 11-7 | 18-2 | 24-0 | Note a | |
| Hem-Fir | #3 | 10-10 | 15-10 | 20-1 | 24-6 | |
| Southern Pine | SS | 12-11 | 20-3 | Note a | Note a | |
| Southern Pine | #1 | 12-5 | 19-6 | 25-8 | Note a | |
| Southern Pine | #2 | 11-10 | 18-8 | 24-7 | Note a | |
| Southern Pine | #3 | 10-1 | 14-11 | 18-9 | 22-9 | |
| Spruce-Pine-Fir | SS | 12-2 | 19-1 | 25-2 | Note a | |
| Spruce-Pine-Fir | #1 | 11-10 | 18-8 | 24-7 | Note a | |
| Spruce-Pine-Fir | #2 | 11-10 | 18-8 | 24-7 | Note a | |
| Spruce-Pine-Fir | #3 | 10-10 | 15-10 | 20-1 | 24-6 | |
| 16 | Douglas Fir-Larch | SS | 11-11 | 18-9 | 24-8 | Note a |
| Douglas Fir-Larch | #1 | 11-6 | 18-1 | 23-10 | Note a | |
| Douglas Fir-Larch | #2 | 11-3 | 17-8 | 23-0 | Note a | |
| Douglas Fir-Larch | #3 | 9-5 | 13-9 | 17-5 | 21-3 | |
| Hem-Fir | SS | 11-3 | 17-8 | 23-4 | Note a | |
| Hem-Fir | #1 | 11-0 | 17-4 | 22-10 | Note a | |
| Hem-Fir | #2 | 10-6 | 16-6 | 21-9 | Note a | |
| Hem-Fir | #3 | 9-5 | 13-9 | 17-5 | 21-3 | |
| Southern Pine | SS | 11-9 | 18-5 | 24-3 | Note a | |
| Southern Pine | #1 | 11-3 | 17-8 | 23-4 | Note a | |
| Southern Pine | #2 | 10-9 | 16-11 | 21-7 | 25-7 | |
| Southern Pine | #3 | 8-9 | 12-11 | 16-3 | 19-9 | |
| Spruce-Pine-Fir | SS | 11-0 | 17-4 | 22-10 | Note a | |
| Spruce-Pine-Fir | #1 | 10-9 | 16-11 | 22-4 | Note a | |
| Spruce-Pine-Fir | #2 | 10-9 | 16-11 | 22-4 | Note a | |
| Spruce-Pine-Fir | #3 | 9-5 | 13-9 | 17-5 | 21-3 | |
| 19.2 | Douglas Fir-Larch | SS | 11-3 | 17-8 | 23-3 | Note a |
| Douglas Fir-Larch | #1 | 10-10 | 17-0 | 22-5 | Note a | |
| Douglas Fir-Larch | #2 | 10-7 | 16-7 | 21-0 | 25-8 | |
| Douglas Fir-Larch | #3 | 8-7 | 12-6 | 15-10 | 19-5 | |
| Hem-Fir | SS | 10-7 | 16-8 | 21-11 | Note a | |
| Hem-Fir | #1 | 10-4 | 16-4 | 21-6 | Note a | |
| Hem-Fir | #2 | 9-11 | 15-7 | 20-6 | 25-3 | |
| Hem-Fir | #3 | 8-7 | 12-6 | 15-10 | 19-5 | |
| Southern Pine | SS | 11-0 | 17-4 | 22-10 | Note a | |
| Southern Pine | #1 | 10-7 | 16-8 | 22-0 | Note a | |
| Southern Pine | #2 | 10-2 | 15-7 | 19-8 | 23-5 | |
| Southern Pine | #3 | 8-0 | 11-9 | 14-10 | 18-0 | |
| Spruce-Pine-Fir | SS | 10-4 | 16-4 | 21-6 | Note a | |
| Spruce-Pine-Fir | #1 | 10-2 | 15-11 | 21-0 | 25-8 | |
| Spruce-Pine-Fir | #2 | 10-2 | 15-11 | 21-0 | 25-8 | |
| Spruce-Pine-Fir | #3 | 8-7 | 12-6 | 15-10 | 19-5 | |
| 24 | Douglas Fir-Larch | SS | 10-5 | 16-4 | 21-7 | Note a |
| Douglas Fir-Larch | #1 | 10-0 | 15-9 | 20-1 | 24-6 | |
| Douglas Fir-Larch | #2 | 9-10 | 14-10 | 18-9 | 22-11 | |
| Douglas Fir-Larch | #3 | 7-8 | 11-2 | 14-2 | 17-4 | |
| Hem-Fir | SS | 9-10 | 15-6 | 20-5 | Note a | |
| Hem-Fir | #1 | 9-8 | 15-2 | 19-7 | 23-11 | |
| Hem-Fir | #2 | 9-2 | 14-5 | 18-6 | 22-7 | |
| Hem-Fir | #3 | 7-8 | 11-2 | 14-2 | 17-4 | |
| Southern Pine | SS | 10-3 | 16-1 | 21-2 | Note a | |
| Southern Pine | #1 | 9-10 | 15-6 | 20-5 | 24-0 | |
| Southern Pine | #2 | 9-3 | 13-11 | 17-7 | 20-11 | |
| Southern Pine | #3 | 7-2 | 10-6 | 13-3 | 16-1 | |
| Spruce-Pine-Fir | SS | 9-8 | 15-2 | 19-11 | 25-5 | |
| Spruce-Pine-Fir | #1 | 9-5 | 14-9 | 18-9 | 22-11 | |
| Spruce-Pine-Fir | #2 | 9-5 | 14-9 | 18-9 | 22-11 | |
| Spruce-Pine-Fir | #3 | 7-8 | 11-2 | 14-2 | 17-4 | |
Check sources for availability of lumber in lengths greater than 20 feet.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
- Span exceeds 26 feet in length.
CEILING JOIST SPANS FOR COMMON LUMBER SPECIES (Uninhabitable attics with limited storage, live load = 20 psf, L/Δ = 240)
| CEILING JOIST SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 psf | ||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | |||
| Maximum ceiling joist spans | ||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 12 | Douglas Fir-Larch | SS | 10-5 | 16-4 | 21-7 | Note a |
| Douglas Fir-Larch | #1 | 10-0 | 15-9 | 20-1 | 24-6 | |
| Douglas Fir-Larch | #2 | 9-10 | 14-10 | 18-9 | 22-11 | |
| Douglas Fir-Larch | #3 | 7-8 | 11-2 | 14-2 | 17-4 | |
| Hem-Fir | SS | 9-10 | 15-6 | 20-5 | Note a | |
| Hem-Fir | #1 | 9-8 | 15-2 | 19-7 | 23-11 | |
| Hem-Fir | #2 | 9-2 | 14-5 | 18-6 | 22-7 | |
| Hem-Fir | #3 | 7-8 | 11-2 | 14-2 | 17-4 | |
| Southern Pine | SS | 10-3 | 16-1 | 21-2 | Note a | |
| Southern Pine | #1 | 9-10 | 15-6 | 20-5 | 24-0 | |
| Southern Pine | #2 | 9-3 | 13-11 | 17-7 | 20-11 | |
| Southern Pine | #3 | 7-2 | 10-6 | 13-3 | 16-1 | |
| Spruce-Pine-Fir | SS | 9-8 | 15-2 | 19-11 | 25-5 | |
| Spruce-Pine-Fir | #1 | 9-5 | 14-9 | 18-9 | 22-11 | |
| Spruce-Pine-Fir | #2 | 9-5 | 14-9 | 18-9 | 22-11 | |
| Spruce-Pine-Fir | #3 | 7-8 | 11-2 | 14-2 | 17-4 | |
| 16 | Douglas Fir-Larch | SS | 9-6 | 14-11 | 19-7 | 25-0 |
| Douglas Fir-Larch | #1 | 9-1 | 13-9 | 17-5 | 21-3 | |
| Douglas Fir-Larch | #2 | 8-9 | 12-10 | 16-3 | 19-10 | |
| Douglas Fir-Larch | #3 | 6-8 | 9-8 | 12-4 | 15-0 | |
| Hem-Fir | SS | 8-11 | 14-1 | 18-6 | 23-8 | |
| Hem-Fir | #1 | 8-9 | 13-5 | 16-10 | 20-8 | |
| Hem-Fir | #2 | 8-4 | 12-8 | 16-0 | 19-7 | |
| Hem-Fir | #3 | 6-8 | 9-8 | 12-4 | 15-0 | |
| Southern Pine | SS | 9-4 | 14-7 | 19-3 | 24-7 | |
| Southern Pine | #1 | 8-11 | 14-0 | 17-9 | 20-9 | |
| Southern Pine | #2 | 8-0 | 12-0 | 15-3 | 18-1 | |
| Southern Pine | #3 | 6-2 | 9-2 | 11-6 | 14-0 | |
| Spruce-Pine-Fir | SS | 8-9 | 13-9 | 18-1 | 23-1 | |
| Spruce-Pine-Fir | #1 | 8-7 | 12-10 | 16-3 | 19-10 | |
| Spruce-Pine-Fir | #2 | 8-7 | 12-10 | 16-3 | 19-10 | |
| Spruce-Pine-Fir | #3 | 6-8 | 9-8 | 12-4 | 15-0 | |
| 19.2 | Douglas Fir-Larch | SS | 8-11 | 14-0 | 18-5 | 23-4 |
| Douglas Fir-Larch | #1 | 8-7 | 12-6 | 15-10 | 19-5 | |
| Douglas Fir-Larch | #2 | 8-0 | 11-9 | 14-10 | 18-2 | |
| Douglas Fir-Larch | #3 | 6-1 | 8-10 | 11-3 | 13-8 | |
| Hem-Fir | SS | 8-5 | 13-3 | 17-5 | 22-3 | |
| Hem-Fir | #1 | 8-3 | 12-3 | 15-6 | 18-11 | |
| Hem-Fir | #2 | 7-10 | 11-7 | 14-8 | 17-10 | |
| Hem-Fir | #3 | 6-1 | 8-10 | 11-3 | 13-8 | |
| Southern Pine | SS | 8-9 | 13-9 | 18-2 | 23-1 | |
| Southern Pine | #1 | 8-5 | 12-9 | 16-2 | 18-11 | |
| Southern Pine | #2 | 7-4 | 11-0 | 13-11 | 16-6 | |
| Southern Pine | #3 | 5-8 | 8-4 | 10-6 | 12-9 | |
| Spruce-Pine-Fir | SS | 8-3 | 12-11 | 17-1 | 21-8 | |
| Spruce-Pine-Fir | #1 | 8-0 | 11-9 | 14-10 | 18-2 | |
| Spruce-Pine-Fir | #2 | 8-0 | 11-9 | 14-10 | 18-2 | |
| Spruce-Pine-Fir | #3 | 6-1 | 8-10 | 11-3 | 13-8 | |
| 24 | Douglas Fir-Larch | SS | 8-3 | 13-0 | 17-1 | 20-11 |
| Douglas Fir-Larch | #1 | 7-8 | 11-2 | 14-2 | 17-4 | |
| Douglas Fir-Larch | #2 | 7-2 | 10-6 | 13-3 | 16-3 | |
| Douglas Fir-Larch | #3 | 5-5 | 7-11 | 10-0 | 12-3 | |
| Hem-Fir | SS | 7-10 | 12-3 | 16-2 | 20-6 | |
| Hem-Fir | #1 | 7-6 | 10-11 | 13-10 | 16-11 | |
| Hem-Fir | #2 | 7-1 | 10-4 | 13-1 | 16-0 | |
| Hem-Fir | #3 | 5-5 | 7-11 | 10-0 | 12-3 | |
| Southern Pine | SS | 8-1 | 12-9 | 16-10 | 21-6 | |
| Southern Pine | #1 | 7-8 | 11-5 | 14-6 | 16-11 | |
| Southern Pine | #2 | 6-7 | 9-10 | 12-6 | 14-9 | |
| Southern Pine | #3 | 5-1 | 7-5 | 9-5 | 11-5 | |
| Spruce-Pine-Fir | SS | 7-8 | 12-0 | 15-10 | 19-5 | |
| Spruce-Pine-Fir | #1 | 7-2 | 10-6 | 13-3 | 16-3 | |
| Spruce-Pine-Fir | #2 | 7-2 | 10-6 | 13-3 | 16-3 | |
| Spruce-Pine-Fir | #3 | 5-5 | 7-11 | 10-0 | 12-3 | |
Check sources for availability of lumber in lengths greater than 20 feet.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
- Span exceeds 26 feet in length.