// CODE SNIPPET
R802.5.1 Ceiling Joist Size
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Ceiling joists shall be sized based on the joist spans in Tables R802.5.1(1) and R802.5.1(2). For other grades and species and for 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 | ||||||
| (feet - inches) | (feet - inches) | (feet - inches) | (feet - inches) | |||
| 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 | 11-1 | 16-3 | 20-7 | 25-2 | |
| 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 | 23-4 | Note a | |
| Douglas fir-larch | #3 | 9-7 | 14-1 | 17-10 | 21-9 | |
| 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 | 23-10 | 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 | 16-8 | 21-4 | 26-0 | |
| Douglas fir-larch | #3 | 8-9 | 12-10 | 16-3 | 19-10 | |
| 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 | 15-0 | 19-1 | 23-3 | |
| Douglas fir-larch | #3 | 7-10 | 11-6 | 14-7 | 17-9 | |
| Hem-fir | SS | 9-10 | 15-6 | 20-5 | Note a | |
| Hem-fir | #1 | 9-8 | 15-2 | 19-10 | 24-3 | |
| 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 | ||||||
| (feet - inches) | (feet - inches) | (feet - inches) | (feet - inches) | |||
| 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 | 15-0 | 19-1 | 23-3 | |
| Douglas fir-larch | #3 | 7-10 | 11-6 | 14-7 | 17-9 | |
| Hem-fir | SS | 9-10 | 15-6 | 20-5 | Note a | |
| Hem-fir | #1 | 9-8 | 15-2 | 19-10 | 24-3 | |
| 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 | 8-11 | 13-0 | 16-6 | 20-2 | |
| Douglas fir-larch | #3 | 6-10 | 9-11 | 12-7 | 15-5 | |
| Hem-fir | SS | 8-11 | 14-1 | 18-6 | 23-8 | |
| Hem-fir | #1 | 8-9 | 13-7 | 17-2 | 21-0 | |
| 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 | 23-7 |
| Douglas fir-larch | #1 | 8-7 | 12-6 | 15-10 | 19-5 | |
| Douglas fir-larch | #2 | 8-2 | 11-11 | 15-1 | 18-5 | |
| Douglas fir-larch | #3 | 6-2 | 9-1 | 11-6 | 14-1 | |
| Hem-fir | SS | 8-5 | 13-3 | 17-5 | 22-3 | |
| Hem-fir | #1 | 8-3 | 12-4 | 15-8 | 19-2 | |
| 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 | 17-2 | 21-3 |
| Douglas fir-larch | #1 | 7-8 | 11-2 | 14-2 | 17-4 | |
| Douglas fir-larch | #2 | 7-3 | 10-8 | 13-6 | 16-5 | |
| Douglas fir-larch | #3 | 5-7 | 8-1 | 10-3 | 12-7 | |
| Hem-fir | SS | 7-10 | 12-3 | 16-2 | 20-6 | |
| Hem-fir | #1 | 7-7 | 11-1 | 14-0 | 17-1 | |
| 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.
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