Code of Massachusetts Regulations
780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS
Chapter 23 - Wood
Section 2308 - CONVENTIONAL LIGHT-FRAME CONSTRUCTION
Subsection 2308.10 - Roof and ceiling framing
Universal Citation: 780 CMR MA Code of Regs 2308.10
Current through Register 1531, September 27, 2024
The framing details required in this section apply to roofs having a minimum slope of three units vertical in 12 units horizontal (25-percent slope) or greater. 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.
2308.10.1 Wind uplift. The roof construction shall have rafter and truss ties to the wall below. Resultant uplift loads shall be transferred to the foundation using a continuous load path. The rafter or truss to wall connection shall comply with Tables 2304.9.1 and 2308.10.1.
TABLE 2308.10.1 REQUIRED RATING OF APPROVED UPLIFT CONNECTORS (pounds)a, b, c, e, f, g, h
| BASIC WIND SPEED (3-second gust) | ROOF SPAN (feet) |
OVERHANGS (pounds/feet)d |
||||||
| 12 | 20 | 24 | 28 | 32 | 36 | 40 | ||
| 85 | -72 | -120 | -145 | -169 | -193 | -217 | -241 | -38.55 |
| 90 | -91 | -151 | -181 | -212 | -242 | -272 | -302 | -43.22 |
| 100 | -131 | -281 | -262 | -305 | -349 | -393 | -436 | -53.36 |
| 110 | -175 | -292 | -351 | -409 | -467 | -526 | -584 | -64.56 |
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile
per hour = 1.61 km/hr, 1 pound = 0.454 Kg, 1 pound per foot = 14.5939 N/m.
a. The uplift connection requirements are based on a 30-foot mean roof height located in Exposure B. For Exposure C or D and for other mean roof heights, multiply the above loads by the adjustment coefficients below. |
| Mean Roof Height (feet) | ||||||||||
| EXPOSURE | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 | 55 | 60 |
| B | 1.00 | 1.00 | 1.00 | 1.00 | 1.05 | 1.09 | 1.12 | 1.16 | 1.19 | 1.22 |
| C | 1.21 | 1.29 | 1.35 | 1.40 | 1.45 | 1.49 | 1.53 | 1.56 | 1.59 | 1.62 |
| D | 1.47 | 1.55 | 1.61 | 1.66 | 1.70 | 1.74 | 1.78 | 1.81 | 1.84 | 1.87 |
| b. The uplift connection requirements are based on the
framing being spaced 24 inches on center. Multiply by 0.67 for framing spaced
16 inches on center and multiply by 0.5 for framing spaced 12 inches on center.
c. The uplift connection requirements include an allowance for 10 pounds of dead load. d. The uplift connection requirements do not account for the effects of overhangs. The magnitude of the above loads shall be increased by adding the overhang loads found in the table. The overhang loads are also based on framing spaced 24 inches on center. The overhang loads given shall be multiplied by the overhang projection and added to the roof uplift value in the table. e. The uplift connection requirements are based upon wind loading on end zones as defined in Figure 6-2 of ASCE 7. Connection loads for connections located a distance of 20 percent of the least horizontal dimension of the building from the corner of the building are permitted to be reduced by multiplying the table connection value by 0.7 and multiplying the overhang load by 0.8. f. For wall-to-wall and wall-to-foundation connections, the capacity of the uplift connector is permitted to be reduced by 100 pounds for each full wall above. (For example, if a 500-pound rated connector is used on the roof framing, a 400-pound rated connector is permitted at the next floor level down). g. Interpolation is permitted for intermediate values of basic wind speeds and roof spans. h. The rated capacity of approved tie-down devices is permitted to include up to a 60-percent increase for wind effects where allowed by material specifications. |
2308.10.2 Ceiling joist spans. Allowable spans for ceiling joists shall be in accordance with Table 2308.10.2(1) or 2308.10.2(2). For other grades and species, refer to the AF & PA Span Tables for Joists and Rafters.
TABLE 2308.10.2(1) CEILING JOIST SPANS FOR COMMON LUMBER SPECIES (Uninhabitable Attics Without Storage, Live Load = 10 pounds per square foot, L/[Delta] = 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 | 12-8 | 19-11 | Note a | Note a | |
| Southern Pine | #2 | 12-5 | 19-6 | 25-8 | Note a | |
| Southern Pine | #3 | 11-6 | 17-0 | 21-8 | 25-7 | |
| 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 | 11-6 | 18-1 | 23-1 | Note a | |
| Southern Pine | #2 | 11-3 | 17-8 | 23-4 | Note a | |
| Southern Pine | #3 | 10-0 | 14-9 | 18-9 | 22-2 | |
| 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 | |
TABLE 2308.10.2(1)-continued CEILING JOIST SPANS FOR COMMON LUMBER SPECIES (Uninhabitable Attics Without Storage, Live Load = 10 pounds per square foot, L/[Delta] = 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.) | |||
| 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 | 10-10 | 17-0 | 22-5 | Note a | |
| Southern Pine | #2 | 10-7 | 16-8 | 21-11 | Note a | |
| Southern Pine | #3 | 9-1 | 13-6 | 17-2 | 20-3 | |
| 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 | 10-0 | 15-9 | 20-10 | Note a | |
| Southern Pine | #2 | 9-10 | 15-6 | 20-1 | 23-11 | |
| Southern Pine | #3 | 8-2 | 12-0 | 15-4 | 18-1 | |
| 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 | |
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
per square foot = 47.8 N/m2. a. Span exceeds 26 feet in length. Check sources for availability of lumber in lengths greater than 20 feet. |
TABLE 2308.10.2(2) CEILING JOIST SPANS FOR COMMON LUMBER SPECIES (Uninhabitable Attics With Limited Storage, Live Load = 20 pounds per square foot, L/[Delta] = 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 | 10-0 | 15-9 | 20-10 | Note a | |
| Southern Pine | #2 | 9-10 | 15-6 | 20-1 | 23-11 | |
| Southern Pine | #3 | 8-2 | 12-0 | 15-4 | 18-1 | |
| 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 | 9-1 | 14-4 | 18-11 | 23-1 | |
| Southern Pine | #2 | 8-11 | 13-6 | 17-5 | 20-9 | |
| Southern Pine | #3 | 7-1 | 10-5 | 13-3 | 15-8 | |
| 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 | |
TABLE 2308.10.2(2)-continued CEILING JOIST SPANS FOR COMMON LUMBER SPECIES (Uninhabitable Attics With Limited Storage, Live Load = 20 pounds per square foot, L/[Delta] = 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.) | |||
| 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 | 18-1 | 23-1 | |
| Southern Pine | #1 | 8-7 | 13-6 | 17-9 | 21-1 | |
| Southern Pine | #2 | 8-5 | 12-3 | 15-10 | 18-11 | |
| Southern Pine | #3 | 6-5 | 9-6 | 12-1 | 14-4 | |
| 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 | 8-0 | 12-6 | 15-10 | 18-10 | |
| Southern Pine | #2 | 7-8 | 11-0 | 14-2 | 16-11 | |
| Southern Pine | #3 | 5-9 | 8-6 | 10-10 | 12-10 | |
| 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 | |
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
per square foot = 47.8 N/m2. a. Span exceeds 26 feet in length. Check sources for availability of lumber in lengths greater than 20 feet. |
2308.10.3 Rafter spans. Allowable spans for rafters shall be in accordance with Table 2308.10.3(1), 2308.10.3(2), 2308.10.3(3), 2308.10.3(4), 2308.10.3(5) or 2308.10.3(6). For other grades and species, refer to the AF & PA Span Tables for Joists and Rafters.
TABLE 2308.10.3(1) RAFTER SPANS FOR COMMON LUMBER SPECIES (Roof Live Load = 20 pounds per square foot, Ceiling Not Attached to Rafters, L/[Delta] = 180)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 psf | |||||||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | |||
| Maximum rafter spans | ||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 12 | Douglas Fir-Larch | SS | 11-6 | 18-0 | 23-9 | Note a | Note a | 11-6 | 18-0 | 23-5 | Note a | Note a |
| Douglas Fir-Larch | #1 | 11-1 | 17-4 | 22-5 | Note a | Note a | 10-6 | 15-4 | 19-5 | 23-9 | Note a | |
| Douglas Fir-Larch | #2 | 10-10 | 16-7 | 21-0 | 25-8 | Note a | 9-10 | 14-4 | 18-2 | 22-3 | 25-9 | |
| Douglas Fir-Larch | #3 | 8-7 | 12-6 | 15-10 | 19-5 | 22-6 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | |
| Hem-Fir | SS | 10-10 | 17-0 | 22-5 | Note a | Note a | 10-10 | 17-0 | 22-5 | Note a | Note a | |
| Hem-Fir | #1 | 10-7 | 16-8 | 21-10 | Note a | Note a | 10-3 | 14-11 | 18-11 | 23-2 | Note a | |
| Hem-Fir | #2 | 10-1 | 15-11 | 20-8 | 25-3 | Note a | 9-8 | 14-2 | 17-11 | 21-11 | 25-5 | |
| Hem-Fir | #3 | 8-7 | 12-6 | 15-10 | 19-5 | 22-6 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | |
| Southern Pine | SS | 11-3 | 17-8 | 23-4 | Note a | Note a | 11-3 | 17-8 | 23-4 | Note a | Note a | |
| Southern Pine | #1 | 11-1 | 17-4 | 22-11 | Note a | Note a | 11-1 | 17-3 | 21-9 | 25-10 | Note a | |
| Southern Pine | #2 | 10-10 | 17-0 | 22-5 | Note a | Note a | 10-6 | 15-1 | 19-5 | 23-2 | Note a | |
| Southern Pine | #3 | 9-1 | 13-6 | 17-2 | 20-3 | 24-1 | 7-11 | 11-8 | 14-10 | 17-6 | 20-11 | |
| Spruce-Pine-Fir | SS | 10-7 | 16-8 | 21-11 | Note a | Note a | 10-7 | 16-8 | 21-9 | Note a | Note a | |
| Spruce-Pine-Fir | #1 | 10-4 | 16-3 | 21-0 | 25-8 | Note a | 9-10 | 14-4 | 18-2 | 22-3 | 25-9 | |
| Spruce-Pine-Fir | #2 | 10-4 | 16-3 | 21-0 | 25-8 | Note a | 9-10 | 14-4 | 18-2 | 22-3 | 25-9 | |
| Spruce-Pine-Fir | #3 | 8-7 | 12-6 | 15-10 | 19-5 | 22-6 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | |
| 16 | Douglas Fir-Larch | SS | 10-5 | 16-4 | 21-7 | Note a | Note a | 10-5 | 16-0 | 20-3 | 24-9 | Note a |
| Douglas Fir-Larch | #1 | 10-0 | 15-4 | 19-5 | 23-9 | Note a | 9-1 | 13-3 | 16-10 | 20-7 | 23-10 | |
| Douglas Fir-Larch | #2 | 9-10 | 14-4 | 18-2 | 22-3 | 25-9 | 8-6 | 12-5 | 15-9 | 19-3 | 22-4 | |
| Douglas Fir-Larch | #3 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | 6-5 | 9-5 | 11-11 | 14-6 | 16-10 | |
| Hem-Fir | SS | 9-10 | 15-6 | 20-5 | Note a | Note a | 9-10 | 15-6 | 19-11 | 24-4 | Note a | |
| Hem-Fir | #1 | 9-8 | 14-11 | 18-11 | 23-2 | Note a | 8-10 | 12-11 | 16-5 | 20-0 | 23-3 | |
| Hem-Fir | #2 | 9-2 | 14-2 | 17-11 | 21-11 | 25-5 | 8-5 | 12-3 | 15-6 | 18-11 | 22-0 | |
| Hem-Fir | #3 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | 6-5 | 9-5 | 11-11 | 14-6 | 16-10 | |
| Southern Pine | SS | 10-3 | 16-1 | 21-2 | Note a | Note a | 10-3 | 16-1 | 21-2 | Note a | Note a | |
| Southern Pine | #1 | 10-0 | 15-9 | 20-10 | 25-10 | Note a | 10-0 | 15-0 | 18-10 | 22-4 | Note a | |
| Southern Pine | #2 | 9-10 | 15-1 | 19-5 | 23-2 | Note a | 9-1 | 13-0 | 16-10 | 20-1 | 23-7 | |
| Southern Pine | #3 | 7-11 | 11-8 | 14-10 | 17-6 | 20-11 | 6-10 | 10-1 | 12-10 | 15-2 | 18-1 | |
| Spruce-Pine-Fir | SS | 9-8 | 15-2 | 19-11 | 25-5 | Note a | 9-8 | 14-10 | 18-10 | 23-0 | Note a | |
| Spruce-Pine-Fir | #1 | 9-5 | 14-4 | 18-2 | 22-3 | 25-9 | 8-6 | 12-5 | 15-9 | 19-3 | 22-4 | |
| Spruce-Pine-Fir | #2 | 9-5 | 14-4 | 18-2 | 22-3 | 25-9 | 8-6 | 12-5 | 15-9 | 19-3 | 22-4 | |
| Spruce-Pine-Fir | #3 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | 6-5 | 9-5 | 11-11 | 14-6 | 16-10 | |
TABLE 2308.10.3(1)-continued RAFTER SPANS FOR COMMON LUMBER SPECIES (Roof Live Load = 20 pounds per square foot, Ceiling Not Attached to Rafters, L/[Delta] = 180)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 pounds psf | |||||||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | |||
| Maximum rafter spans | ||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 19.2 | Douglas Fir-Larch | SS | 9-10 | 15-5 | 20-4 | 25-11 | Note a | 9-10 | 14-7 | 18-6 | 22-7 | Note a |
| Douglas Fir-Larch | #1 | 9-5 | 14-0 | 17-9 | 21-8 | 25-2 | 8-4 | 12-2 | 15-4 | 18-9 | 21-9 | |
| Douglas Fir-Larch | #2 | 8-11 | 13-1 | 16-7 | 20-3 | 23-6 | 7-9 | 11-4 | 14-4 | 17-7 | 20-4 | |
| Douglas Fir-Larch | #3 | 6-9 | 9-11 | 12-7 | 15-4 | 17-9 | 5-10 | 8-7 | 10-10 | 13-3 | 15-5 | |
| Hem-Fir | SS | 9-3 | 14-7 | 19-2 | 24-6 | Note a | 9-3 | 14-4 | 18-2 | 22-3 | 25-9 | |
| Hem-Fir | #1 | 9-1 | 13-8 | 17-4 | 21-1 | 24-6 | 8-1 | 11-10 | 15-0 | 18-4 | 21-3 | |
| Hem-Fir | #2 | 8-8 | 12-11 | 16-4 | 20-0 | 23-2 | 7-8 | 11-2 | 14-2 | 17-4 | 20-1 | |
| Hem-Fir | #3 | 6-9 | 9-11 | 12-7 | 15-4 | 17-9 | 5-10 | 8-7 | 10-10 | 13-3 | 15-5 | |
| Southern Pine | SS | 9-8 | 15-2 | 19-11 | 25-5 | Note a | 9-8 | 15-2 | 19-11 | 25-5 | Note a | |
| Southern Pine | #1 | 9-5 | 14-10 | 19-7 | 23-7 | Note a | 9-3 | 13-8 | 17-2 | 20-5 | 24-4 | |
| Southern Pine | #2 | 9-3 | 13-9 | 17-9 | 21-2 | 24-10 | 8-4 | 11-11 | 15-4 | 18-4 | 21-6 | |
| Southern Pine | #3 | 7-3 | 10-8 | 13-7 | 16-0 | 19-1 | 6-3 | 9-3 | 11-9 | 13-10 | 16-6 | |
| Spruce-Pine-Fir | SS | 9-1 | 14-3 | 18-9 | 23-11 | Note a | 9-1 | 13-7 | 17-2 | 21-0 | 24-4 | |
| Spruce-Pine-Fir | #1 | 8-10 | 13-1 | 16-7 | 20-3 | 23-6 | 7-9 | 11-4 | 14-4 | 17-7 | 20-4 | |
| Spruce-Pine-Fir | #2 | 8-10 | 13-1 | 16-7 | 20-3 | 23-6 | 7-9 | 11-4 | 14-4 | 17-7 | 20-4 | |
| Spruce-Pine-Fir | #3 | 6-9 | 9-11 | 12-7 | 15-4 | 17-9 | 5-10 | 8-7 | 10-10 | 13-3 | 15-5 | |
| 24 | Douglas Fir-Larch | SS | 9-1 | 14-4 | 18-10 | 23-4 | Note a | 8-11 | 13-1 | 16-7 | 20-3 | 23-5 |
| Douglas Fir-Larch | #1 | 8-7 | 12-6 | 15-10 | 19-5 | 22-6 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | |
| Douglas Fir-Larch | #2 | 8-0 | 11-9 | 14-10 | 18-2 | 21-0 | 6-11 | 10-2 | 12-10 | 15-8 | 18-3 | |
| Douglas Fir-Larch | #3 | 6-1 | 8-10 | 11-3 | 13-8 | 15-11 | 5-3 | 7-8 | 9-9 | 11-10 | 13-9 | |
| Hem-Fir | SS | 8-7 | 13-6 | 17-10 | 22-9 | Note a | 8-7 | 12-10 | 16-3 | 19-10 | 23-0 | |
| Hem-Fir | #1 | 8-4 | 12-3 | 15-6 | 18-11 | 21-11 | 7-3 | 10-7 | 13-5 | 16-4 | 19-0 | |
| Hem-Fir | #2 | 7-11 | 11-7 | 14-8 | 17-10 | 20-9 | 6-10 | 10-0 | 12-8 | 15-6 | 17-11 | |
| Hem-Fir | #3 | 6-1 | 8-10 | 11-3 | 13-8 | 15-11 | 5-3 | 7-8 | 9-9 | 11-10 | 13-9 | |
| Southern Pine | SS | 8-11 | 14-1 | 18-6 | 23-8 | Note a | 8-11 | 14-1 | 18-6 | 22-11 | Note a | |
| Southern Pine | #1 | 8-9 | 13-9 | 17-9 | 21-1 | 25-2 | 8-3 | 12-3 | 15-4 | 18-3 | 21-9 | |
| Southern Pine | #2 | 8-7 | 12-3 | 15-10 | 18-11 | 22-2 | 7-5 | 10-8 | 13-9 | 16-5 | 19-3 | |
| Southern Pine | #3 | 6-5 | 9-6 | 12-1 | 14-4 | 17-1 | 5-7 | 8-3 | 10-6 | 12-5 | 14-9 | |
| Spruce-Pine-Fir | SS | 8-5 | 13-3 | 17-5 | 21-8 | 25-2 | 8-4 | 12-2 | 15-4 | 18-9 | 21-9 | |
| Spruce-Pine-Fir | #1 | 8-0 | 11-9 | 14-10 | 18-2 | 21-0 | 6-11 | 10-2 | 12-10 | 15-8 | 18-3 | |
| Spruce-Pine-Fir | #2 | 8-0 | 11-9 | 14-10 | 18-2 | 21-0 | 6-11 | 10-2 | 12-10 | 15-8 | 18-3 | |
| Spruce-Pine-Fir | #3 | 6-1 | 8-10 | 11-3 | 13-8 | 15-11 | 5-3 | 7-8 | 9-9 | 11-10 | 13-9 | |
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
per square foot = 47.9 N/m2. a. Span exceeds 26 feet in length. Check sources for availability of lumber in lengths greater than 20 feet. |
TABLE 2308.10.3(2) RAFTER SPANS FOR COMMON LUMBER SPECIES (Roof Live Load = 20 pounds per square foot, Ceiling Not Attached to Rafters, L/[Delta] = 240)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 pounds psf | ||||||||||
| 2 × 4 | 2 × 6 | 2 ×8 | 2 × 10 | 2 × 12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | ||||
| Maximum rafter spans | |||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | ||||
| 12 | Douglas Fir-Larch | SS | 10-5 | 16-4 | 21-7 | Note a | Note a | 10-5 | 16-4 | 21-7 | Note a | Note a | |
| Douglas Fir-Larch | #1 | 10-0 | 15-9 | 20-10 | Note a | Note a | 10-0 | 15-4 | 19-5 | 23-9 | Note a | ||
| Douglas Fir-Larch | #2 | 9-10 | 15-6 | 20-5 | 25-8 | Note a | 9-10 | 14-4 | 18-2 | 22-3 | 25-9 | ||
| Douglas Fir-Larch | #3 | 8-7 | 12-6 | 15-10 | 19-5 | 22-6 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | ||
| Hem-Fir | SS | 9-10 | 15-6 | 20-5 | Note a | Note a | 9-10 | 15-6 | 20-5 | Note a | Note a | ||
| Hem-Fir | #1 | 9-8 | 15-2 | 19-11 | 25-5 | Note a | 9-8 | 14-11 | 18-11 | 23-2 | Note a | ||
| Hem-Fir | #2 | 9-2 | 14-5 | 19-0 | 24-3 | Note a | 9-2 | 14-2 | 17-11 | 21-11 | 25-5 | ||
| Hem-Fir | #3 | 8-7 | 12-6 | 15-10 | 19-5 | 22-6 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | ||
| Southern Pine | SS | 10-3 | 16-1 | 21-2 | Note a | Note a | 10-3 | 16-1 | 21-2 | Note a | Note a | ||
| Southern Pine | #1 | 10-0 | 15-9 | 20-10 | Note a | Note a | 10-0 | 15-9 | 20-10 | 25-10 | Note a | ||
| Southern Pine | #2 | 9-10 | 15-6 | 20-5 | Note a | Note a | 9-10 | 15-1 | 19-5 | 23-2 | Note a | ||
| Southern Pine | #3 | 9-1 | 13-6 | 17-2 | 20-3 | 24-1 | 7-11 | 11-8 | 14-10 | 17-6 | 20-11 | ||
| Spruce-Pine-Fir | SS | 9-8 | 15-2 | 19-11 | 25-5 | Note a | 9-8 | 15-2 | 19-11 | 25-5 | Note a | ||
| Spruce-Pine-Fir | #1 | 9-5 | 14-9 | 19-6 | 24-10 | Note a | 9-5 | 14-4 | 18-2 | 22-3 | 25-9 | ||
| Spruce-Pine-Fir | #2 | 9-5 | 14-9 | 19-6 | 24-10 | Note a | 9-5 | 14-4 | 18-2 | 22-3 | 25-9 | ||
| Spruce-Pine-Fir | #3 | 8-7 | 12-6 | 15-10 | 19-5 | 22-6 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | ||
| 16 | Douglas Fir-Larch | SS | 9-6 | 14-11 | 19-7 | 25-0 | Note a | 9-6 | 14-11 | 19-7 | 24-9 | Note a | |
| Douglas Fir-Larch | #1 | 9-1 | 14-4 | 18-11 | 23-9 | Note a | 9-1 | 13-3 | 16-10 | 20-7 | 23-10 | ||
| Douglas Fir-Larch | #2 | 8-11 | 14-1 | 18-2 | 22-3 | 25-9 | 8-6 | 12-5 | 15-9 | 19-3 | 22-4 | ||
| Douglas Fir-Larch | #3 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | 6-5 | 9-5 | 11-11 | 14-6 | 16-10 | ||
| Hem-Fir | SS | 8-11 | 14-1 | 18-6 | 23-8 | Note a | 8-11 | 14-1 | 18-6 | 23-8 | Note a | ||
| Hem-Fir | #1 | 8-9 | 13-9 | 18-1 | 23-1 | Note a | 8-9 | 12-11 | 16-5 | 20-0 | 23-3 | ||
| Hem-Fir | #2 | 8-4 | 13-1 | 17-3 | 21-11 | 25-5 | 8-4 | 12-3 | 15-6 | 18-11 | 22-0 | ||
| Hem-Fir | #3 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | 6-5 | 9-5 | 11-11 | 14-6 | 16-10 | ||
| Southern Pine | SS | 9-4 | 14-7 | 19-3 | 24-7 | Note a | 9-4 | 14-7 | 19-3 | 24-7 | Note a | ||
| Southern Pine | #1 | 9-1 | 14-4 | 18-11 | 24-1 | Note a | 9-1 | 14-4 | 18-10 | 22-4 | Note a | ||
| Southern Pine | #2 | 8-11 | 14-1 | 18-6 | 23-2 | Note a | 8-11 | 13-0 | 16-10 | 20-1 | 23-7 | ||
| Southern Pine | #3 | 7-11 | 11-8 | 14-10 | 17-6 | 20-11 | 6-10 | 10-1 | 12-10 | 15-2 | 18-1 | ||
| Spruce-Pine-Fir | SS | 8-9 | 13-9 | 18-1 | 23-1 | Note a | 8-9 | 13-9 | 18-1 | 23-0 | Note a | ||
| Spruce-Pine-Fir | #1 | 8-7 | 13-5 | 17-9 | 22-3 | 25-9 | 8-6 | 12-5 | 15-9 | 19-3 | 22-4 | ||
| Spruce-Pine-Fir | #2 | 8-7 | 13-5 | 17-9 | 22-3 | 25-9 | 8-6 | 12-5 | 15-9 | 19-3 | 22-4 | ||
| Spruce-Pine-Fir | #3 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | 6-5 | 9-5 | 11-11 | 14-6 | 16-10 | ||
TABLE 2308.10.3(2)-continued RAFTER SPANS FOR COMMON LUMBER SPECIES (Roof Live Load = 20 pounds per square foot, Ceiling Not Attached to Rafters, L/[Delta] = 240)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 pounds psf | ||||||||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | ||||
| Maximum rafter spans | |||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | ||||
| 19.2 | Douglas Fir-Larch | SS | 8-11 | 14-0 | 18-5 | 23-7 | Note a | 8-11 | 14-0 | 18-5 | 22-7 | Note a | |
| Douglas Fir-Larch | #1 | 8-7 | 13-6 | 17-9 | 21-8 | 25-2 | 8-4 | 12-2 | 15-4 | 18-9 | 21-9 | ||
| Douglas Fir-Larch | #2 | 8-5 | 13-1 | 16-7 | 20-3 | 23-6 | 7-9 | 11-4 | 14-4 | 17-7 | 20-4 | ||
| Douglas Fir-Larch | #3 | 6-9 | 9-11 | 12-7 | 15-4 | 17-9 | 5-10 | 8-7 | 10-10 | 13-3 | 15-5 | ||
| Hem-Fir | SS | 8-5 | 13-3 | 17-5 | 22-3 | Note a | 8-5 | 13-3 | 17-5 | 22-3 | 25-9 | ||
| Hem-Fir | #1 | 8-3 | 12-11 | 17-1 | 21-1 | 24-6 | 8-1 | 11-10 | 15-0 | 18-4 | 21-3 | ||
| Hem-Fir | #2 | 7-10 | 12-4 | 16-3 | 20-0 | 23-2 | 7-8 | 11-2 | 14-2 | 17-4 | 20-1 | ||
| Hem-Fir | #3 | 6-9 | 9-11 | 12-7 | 15-4 | 17-9 | 5-10 | 8-7 | 10-10 | 13-3 | 15-5 | ||
| Southern Pine | SS | 8-9 | 13-9 | 18-1 | 23-1 | Note a | 8-9 | 13-9 | 18-1 | 23-1 | Note a | ||
| Southern Pine | #1 | 8-7 | 13-6 | 17-9 | 22-8 | Note a | 8-7 | 13-6 | 17-2 | 20-5 | 24-4 | ||
| Southern Pine | #2 | 8-5 | 13-3 | 17-5 | 21-2 | 24-10 | 8-4 | 11-11 | 15-4 | 18-4 | 21-6 | ||
| Southern Pine | #3 | 7-3 | 10-8 | 13-7 | 16-0 | 19-1 | 6-3 | 9-3 | 11-9 | 13-10 | 16-6 | ||
| Spruce-Pine-Fir | SS | 8-3 | 12-11 | 17-1 | 21-9 | Note a | 8-3 | 12-11 | 17-1 | 21-0 | 24-4 | ||
| Spruce-Pine-Fir | #1 | 8-1 | 12-8 | 16-7 | 20-3 | 23-6 | 7-9 | 11-4 | 14-4 | 17-7 | 20-4 | ||
| Spruce-Pine-Fir | #2 | 8-1 | 12-8 | 16-7 | 20-3 | 23-6 | 7-9 | 11-4 | 14-4 | 17-7 | 20-4 | ||
| Spruce-Pine-Fir | #3 | 6-9 | 9-11 | 12-7 | 15-4 | 17-9 | 5-10 | 8-7 | 10-10 | 13-3 | 15-5 | ||
| 24 | Douglas Fir-Larch | SS | 8-3 | 13-0 | 17-2 | 21-10 | Note a | 8-3 | 13-0 | 16-7 | 20-3 | 23-5 | |
| Douglas Fir-Larch | #1 | 8-0 | 12-6 | 15-10 | 19-5 | 22-6 | 7-5 | 10-10 | 13-9 | 16-9 | 19-6 | ||
| Douglas Fir-Larch | #2 | 7-10 | 11-9 | 14-10 | 18-2 | 21-0 | 6-11 | 10-2 | 12-10 | 15-8 | 18-3 | ||
| Douglas Fir-Larch | #3 | 6-1 | 8-10 | 11-3 | 13-8 | 15-11 | 5-3 | 7-8 | 9-9 | 11-10 | 13-9 | ||
| Hem-Fir | SS | 7-10 | 12-3 | 16-2 | 20-8 | 25-1 | 7-10 | 12-3 | 16-2 | 19-10 | 23-0 | ||
| Hem-Fir | #1 | 7-8 | 12-0 | 15-6 | 18-11 | 21-11 | 7-3 | 10-7 | 13-5 | 16-4 | 19-0 | ||
| Hem-Fir | #2 | 7-3 | 11-5 | 14-8 | 17-10 | 20-9 | 6-10 | 10-0 | 12-8 | 15-6 | 17-11 | ||
| Hem-Fir | #3 | 6-1 | 8-10 | 11-3 | 13-8 | 15-11 | 5-3 | 7-8 | 9-9 | 11-10 | 13-9 | ||
| Southern Pine | SS | 8-1 | 12-9 | 16-10 | 21-6 | Note a | 8-1 | 12-9 | 16-10 | 21-6 | Note a | ||
| Southern Pine | #1 | 8-0 | 12-6 | 16-6 | 21-1 | 25-2 | 8-0 | 12-3 | 15-4 | 18-3 | 21-9 | ||
| Southern Pine | #2 | 7-10 | 12-3 | 15-10 | 18-11 | 22-2 | 7-5 | 10-8 | 13-9 | 16-5 | 19-3 | ||
| Southern Pine | #3 | 6-5 | 9-6 | 12-1 | 14-4 | 17-1 | 5-7 | 8-3 | 10-6 | 12-5 | 14-9 | ||
| Spruce-Pine-Fir | SS | 7-8 | 12-0 | 15-10 | 20-2 | 24-7 | 7-8 | 12-0 | 15-4 | 18-9 | 21-9 | ||
| Spruce-Pine-Fir | #1 | 7-6 | 11-9 | 14-10 | 18-2 | 21-0 | 6-11 | 10-2 | 12-10 | 15-8 | 18-3 | ||
| Spruce-Pine-Fir | #2 | 7-6 | 11-9 | 14-10 | 18-2 | 21-0 | 6-11 | 10-2 | 12-10 | 15-8 | 18-3 | ||
| Spruce-Pine-Fir | #3 | 6-1 | 8-10 | 11-3 | 13-8 | 15-11 | 5-3 | 7-8 | 9-9 | 11-10 | 13-9 | ||
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
per square foot = 47.9 N/m2. a. Span exceeds 26 feet in length. Check sources for availability of lumber in lengths greater than 20 feet. |
TABLE 2308.10.3(3) RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground Snow Load = 30 pounds per square foot, Ceiling Not Attached to Rafters, L/[Delta] = 180)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 pounds psf | |||||||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | |||
| Maximum rafter spans | ||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 12 | Douglas Fir-Larch | SS | 10-0 | 15-9 | 20-9 | Note a | Note a | 10-0 | 15-9 | 20-1 | 24-6 | Note a |
| Douglas Fir-Larch | #1 | 9-8 | 14-9 | 18-8 | 22-9 | Note a | 9-0 | 13-2 | 16-8 | 20-4 | 23-7 | |
| Douglas Fir-Larch | #2 | 9-5 | 13-9 | 17-5 | 21-4 | 24-8 | 8-5 | 12-4 | 15-7 | 19-1 | 22-1 | |
| Douglas Fir-Larch | #3 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | 6-4 | 9-4 | 11-9 | 14-5 | 16-8 | |
| Hem-Fir | SS | 9-6 | 14-10 | 19-7 | 25-0 | Note a | 9-6 | 14-10 | 19-7 | 24-1 | Note a | |
| Hem-Fir | #1 | 9-3 | 14-4 | 18-2 | 22-2 | 25-9 | 8-9 | 12-10 | 16-3 | 19-10 | 23-0 | |
| Hem-Fir | #2 | 8-10 | 13-7 | 17-2 | 21-0 | 24-4 | 8-4 | 12-2 | 15-4 | 18-9 | 21-9 | |
| Hem-Fir | #3 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | 6-4 | 9-4 | 11-9 | 14-5 | 16-8 | |
| Southern Pine | SS | 9-10 | 15-6 | 20-5 | Note a | Note a | 9-10 | 15-6 | 20-5 | Note a | Note a | |
| Southern Pine | #1 | 9-8 | 15-2 | 20-0 | 24-9 | Note a | 9-8 | 14-10 | 18-8 | 22-2 | Note a | |
| Southern Pine | #2 | 9-6 | 14-5 | 18-8 | 22-3 | Note a | 9-0 | 12-11 | 16-8 | 19-11 | 23-4 | |
| Southern Pine | #3 | 7-7 | 11-2 | 14-3 | 16-10 | 20-0 | 6-9 | 10-0 | 12-9 | 15-1 | 17-11 | |
| Spruce-Pine-Fir | SS | 9-3 | 14-7 | 19-2 | 24-6 | Note a | 9-3 | 14-7 | 18-8 | 22-9 | Note a | |
| Spruce-Pine-Fir | #1 | 9-1 | 13-9 | 17-5 | 21-4 | 24-8 | 8-5 | 12-4 | 15-7 | 19-1 | 22-1 | |
| Spruce-Pine-Fir | #2 | 9-1 | 13-9 | 17-5 | 21-4 | 24-8 | 8-5 | 12-4 | 15-7 | 19-1 | 22-1 | |
| Spruce-Pine-Fir | #3 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | 6-4 | 9-4 | 11-9 | 14-5 | 16-8 | |
| 16 | Douglas Fir-Larch | SS | 9-1 | 14-4 | 18-10 | 23-9 | Note a | 9-1 | 13-9 | 17-5 | 21-3 | 24-8 |
| Douglas Fir-Larch | #1 | 8-9 | 12-9 | 16-2 | 19-9 | 22-10 | 7-10 | 11-5 | 14-5 | 17-8 | 20-5 | |
| Douglas Fir-Larch | #2 | 8-2 | 11-11 | 15-1 | 18-5 | 21-5 | 7-3 | 10-8 | 13-6 | 16-6 | 19-2 | |
| Douglas Fir-Larch | #3 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | 5-6 | 8-1 | 10-3 | 12-6 | 14-6 | |
| Hem-Fir | SS | 8-7 | 13-6 | 17-10 | 22-9 | Note a | 8-7 | 13-6 | 17-1 | 20-10 | 24-2 | |
| Hem-Fir | #1 | 8-5 | 12-5 | 15-9 | 19-3 | 22-3 | 7-7 | 11-1 | 14-1 | 17-2 | 19-11 | |
| Hem-Fir | #2 | 8-0 | 11-9 | 14-11 | 18-2 | 21-1 | 7-2 | 10-6 | 13-4 | 16-3 | 18-10 | |
| Hem-Fir | #3 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | 5-6 | 8-1 | 10-3 | 12-6 | 14-6 | |
| Southern Pine | SS | 8-11 | 14-1 | 18-6 | 23-8 | Note a | 8-11 | 14-1 | 18-6 | 23-8 | Note a | |
| Southern Pine | #1 | 8-9 | 13-9 | 18-1 | 21-5 | 25-7 | 8-8 | 12-10 | 16-2 | 19-2 | 22-10 | |
| Southern Pine | #2 | 8-7 | 12-6 | 16-2 | 19-3 | 22-7 | 7-10 | 11-2 | 14-5 | 17-3 | 20-2 | |
| Southern Pine | #3 | 6-7 | 9-8 | 12-4 | 14-7 | 17-4 | 5-10 | 8-8 | 11-0 | 13-0 | 15-6 | |
| Spruce-Pine-Fir | SS | 8-5 | 13-3 | 17-5 | 22-1 | 25-7 | 8-5 | 12-9 | 16-2 | 19-9 | 22-10 | |
| Spruce-Pine-Fir | #1 | 8-2 | 11-11 | 15-1 | 18-5 | 21-5 | 7-3 | 10-8 | 13-6 | 16-6 | 19-2 | |
| Spruce-Pine-Fir | #2 | 8-2 | 11-11 | 15-1 | 18-5 | 21-5 | 7-3 | 10-8 | 13-6 | 16-6 | 19-2 | |
| Spruce-Pine-Fir | #3 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | 5-6 | 8-1 | 10-3 | 12-6 | 14-6 | |
TABLE 2308.10.3(3)-continued RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground Snow Load = 30 pounds per square foot, Ceiling Not Attached to Rafters, L/[Delta] = 180)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 pounds psf | |||||||||
| 2 × 4 | 2 × 6 | 2×8 | 2 ×10 | 2×12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | |||
| Maximum rafter spans | ||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 19.2 | Douglas Fir-Larch | SS | 8-7 | 13-6 | 17-9 | 21-8 | 25-2 | 8-7 | 12-6 | 15-10 | 19-5 | 22-6 |
| Douglas Fir-Larch | #1 | 7-11 | 11-8 | 14-9 | 18-0 | 20-11 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | |
| Douglas Fir-Larch | #2 | 7-5 | 10-11 | 13-9 | 16-10 | 19-6 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | |
| Douglas Fir-Larch | #3 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | |
| Hem-Fir | SS | 8-1 | 12-9 | 16-9 | 21-4 | 24-8 | 8-1 | 12-4 | 15-7 | 19-1 | 22-1 | |
| Hem-Fir | #1 | 7-9 | 11-4 | 14-4 | 17-7 | 20-4 | 6-11 | 10-2 | 12-10 | 15-8 | 18-2 | |
| Hem-Fir | #2 | 7-4 | 10-9 | 13-7 | 16-7 | 19-3 | 6-7 | 9-7 | 12-2 | 14-10 | 17-3 | |
| Hem-Fir | #3 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | |
| Southern Pine | SS | 8-5 | 13-3 | 17-5 | 22-3 | Note a | 8-5 | 13-3 | 17-5 | 22-0 | 25-9 | |
| Southern Pine | #1 | 8-3 | 13-0 | 16-6 | 19-7 | 23-4 | 7-11 | 11-9 | 14-9 | 17-6 | 20-11 | |
| Southern Pine | #2 | 7-11 | 11-5 | 14-9 | 17-7 | 20-7 | 7-1 | 10-2 | 13-2 | 15-9 | 18-5 | |
| Southern Pine | #3 | 6-0 | 8-10 | 11-3 | 13-4 | 15-10 | 5-4 | 7-11 | 10-1 | 11-11 | 14-2 | |
| Spruce-Pine-Fir | SS | 7-11 | 12-5 | 16-5 | 20-2 | 23-4 | 7-11 | 11-8 | 14-9 | 18-0 | 20-11 | |
| Spruce-Pine-Fir | #1 | 7-5 | 10-11 | 13-9 | 16-10 | 19-6 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | |
| Spruce-Pine-Fir | #2 | 7-5 | 10-11 | 13-9 | 16-10 | 19-6 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | |
| Spruce-Pine-Fir | #3 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | |
| 24 | Douglas Fir-Larch | SS | 7-11 | 12-6 | 15-10 | 19-5 | 22-6 | 7-8 | 11-3 | 14-2 | 17-4 | 20-1 |
| Douglas Fir-Larch | #1 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | 6-4 | 9-4 | 11-9 | 14-5 | 16-8 | |
| Douglas Fir-Larch | #2 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | 5-11 | 8-8 | 11-0 | 13-6 | 15-7 | |
| Douglas Fir-Larch | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-6 | 6-7 | 8-4 | 10-2 | 11-10 | |
| Hem-Fir | SS | 7-6 | 11-10 | 15-7 | 19-1 | 22-1 | 7-6 | 11-0 | 13-11 | 17-0 | 19-9 | |
| Hem-Fir | #1 | 6-11 | 10-2 | 12-10 | 15-8 | 18-2 | 6-2 | 9-1 | 11-6 | 14-0 | 16-3 | |
| Hem-Fir | #2 | 6-7 | 9-7 | 12-2 | 14-10 | 17-3 | 5-10 | 8-7 | 10-10 | 13-3 | 15-5 | |
| Hem-Fir | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-6 | 6-7 | 8-4 | 10-2 | 11-10 | |
| Southern Pine | SS | 7-10 | 12-3 | 16-2 | 20-8 | 25-1 | 7-10 | 12-3 | 16-2 | 19-8 | 23-0 | |
| Southern Pine | #1 | 7-8 | 11-9 | 14-9 | 17-6 | 20-11 | 7-1 | 10-6 | 13-2 | 15-8 | 18-8 | |
| Southern Pine | #2 | 7-1 | 10-2 | 13-2 | 15-9 | 18-5 | 6-4 | 9-2 | 11-9 | 14-1 | 16-6 | |
| Southern Pine | #3 | 5-4 | 7-11 | 10-1 | 11-11 | 14-2 | 4-9 | 7-1 | 9-0 | 10-8 | 12-8 | |
| Spruce-Pine-Fir | SS | 7-4 | 11-7 | 14-9 | 18-0 | 20-11 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | |
| Spruce-Pine-Fir | #1 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | 5-11 | 8-8 | 11-0 | 13-6 | 15-7 | |
| Spruce-Pine-Fir | #2 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | 5-11 | 8-8 | 11-0 | 13-6 | 15-7 | |
| Spruce-Pine-Fir | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-6 | 6-7 | 8-4 | 10-2 | 11-10 | |
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
per square foot = 47.9 N/m2. a. Span exceeds 26 feet in length. Check sources for availability of lumber in lengths greater than 20 feet. |
TABLE 2308.10.3(4) RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground Snow Load = 50 pounds per square foot, Ceiling Not Attached to Rafters, L/[Delta] = 180)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 pounds psf | ||||||||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | ||||
| Maximum rafter spans | |||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | ||||
| 12 | Douglas Fir-Larch | SS | 8-5 | 13-3 | 17-6 | 22-4 | 26-0 | 8-5 | 13-3 | 17-0 | 20-9 | 24-10 | |
| Douglas Fir-Larch | #1 | 8-2 | 12-0 | 15-3 | 18-7 | 21-7 | 7-7 | 11-2 | 14-1 | 17-3 | 20-0 | ||
| Douglas Fir-Larch | #2 | 7-8 | 11-3 | 14-3 | 17-5 | 20-2 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | ||
| Douglas Fir-Larch | #3 | 5-10 | 8-6 | 10-9 | 13-2 | 15-3 | 5-5 | 7-10 | 10-0 | 12-2 | 14-1 | ||
| Hem-Fir | SS | 8-0 | 12-6 | 16-6 | 21-1 | 25-6 | 8-0 | 12-6 | 16-6 | 20-4 | 23-7 | ||
| Hem-Fir | #1 | 7-10 | 11-9 | 14-10 | 18-1 | 21-0 | 7-5 | 10-10 | 13-9 | 16-9 | 19-5 | ||
| Hem-Fir | #2 | 7-5 | 11-1 | 14-0 | 17-2 | 19-11 | 7-0 | 10-3 | 13-0 | 15-10 | 18-5 | ||
| Hem-Fir | #3 | 5-10 | 8-6 | 10-9 | 13-2 | 15-3 | 5-5 | 7-10 | 10-0 | 12-2 | 14-1 | ||
| Southern Pine | SS | 8-4 | 13-0 | 17-2 | 21-11 | Note a | 8-4 | 13-0 | 17-2 | 21-11 | Note a | ||
| Southern Pine | #1 | 8-2 | 12-10 | 16-10 | 20-3 | 24-1 | 8-2 | 12-6 | 15-9 | 18-9 | 22-4 | ||
| Southern Pine | #2 | 8-0 | 11-9 | 15-3 | 18-2 | 21-3 | 7-7 | 10-11 | 14-1 | 16-10 | 19-9 | ||
| Southern Pine | #3 | 6-2 | 9-2 | 11-8 | 13-9 | 16-4 | 5-9 | 8-5 | 10-9 | 12-9 | 15-2 | ||
| Spruce-Pine-Fir | SS | 7-10 | 12-3 | 16-2 | 20-8 | 24-1 | 7-10 | 12-3 | 15-9 | 19-3 | 22-4 | ||
| Spruce-Pine-Fir | #1 | 7-8 | 11-3 | 14-3 | 17-5 | 20-2 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | ||
| Spruce-Pine-Fir | #2 | 7-8 | 11-3 | 14-3 | 17-5 | 20-2 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | ||
| Spruce-Pine-Fir | #3 | 5-10 | 8-6 | 10-9 | 13-2 | 15-3 | 5-5 | 7-10 | 10-0 | 12-2 | 14-1 | ||
| 16 | Douglas Fir-Larch | SS | 7-8 | 12-1 | 15-10 | 19-5 | 22-6 | 7-8 | 11-7 | 14-8 | 17-11 | 20-10 | |
| Douglas Fir-Larch | #1 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | 6-7 | 9-8 | 12-2 | 14-11 | 17-3 | ||
| Douglas Fir-Larch | #2 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | ||
| Douglas Fir-Larch | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-8 | 6-10 | 8-8 | 10-6 | 12-3 | ||
| Hem-Fir | SS | 7-3 | 11-5 | 15-0 | 19-1 | 22-1 | 7-3 | 11-5 | 14-5 | 17-8 | 20-5 | ||
| Hem-Fir | #1 | 6-11 | 10-2 | 12-10 | 15-8 | 18-2 | 6-5 | 9-5 | 11-11 | 14-6 | 16-10 | ||
| Hem-Fir | #2 | 6-7 | 9-7 | 12-2 | 14-10 | 17-3 | 6-1 | 8-11 | 11-3 | 13-9 | 15-11 | ||
| Hem-Fir | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-8 | 6-10 | 8-8 | 10-6 | 12-3 | ||
| Southern Pine | SS | 7-6 | 11-10 | 15-7 | 19-11 | 24-3 | 7-6 | 11-10 | 15-7 | 19-11 | 23-10 | ||
| Southern Pine | #1 | 7-5 | 11-7 | 14-9 | 17-6 | 20-11 | 7-4 | 10-10 | 13-8 | 16-2 | 19-4 | ||
| Southern Pine | #2 | 7-1 | 10-2 | 13-2 | 15-9 | 18-5 | 6-7 | 9-5 | 12-2 | 14-7 | 17-1 | ||
| Southern Pine | #3 | 5-4 | 7-11 | 10-1 | 11-11 | 14-2 | 4-11 | 7-4 | 9-4 | 11-0 | 13-1 | ||
| Spruce-Pine-Fir | SS | 7-1 | 11-2 | 14-8 | 18-0 | 20-11 | 7-1 | 10-9 | 13-8 | 16-8 | 19-4 | ||
| Spruce-Pine-Fir | #1 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | ||
| Spruce-Pine-Fir | #2 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | ||
| Spruce-Pine-Fir | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-8 | 6-10 | 8-8 | 10-6 | 12-3 | ||
TABLE 2308.10.3(4)-continued RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground Snow Load = 50 pounds per square foot, Ceiling Not Attached to Rafters, L/[Delta] = 180)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 pounds psf | ||||||||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | ||||
| Maximum rafter spans | |||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | ||||
| 19.2 | Douglas Fir-Larch | SS | 7-3 | 11-4 | 14-6 | 17-8 | 20-6 | 7-3 | 10-7 | 13-5 | 16-5 | 19-0 | |
| Douglas Fir-Larch | #1 | 6-6 | 9-6 | 12-0 | 14-8 | 17-1 | 6-0 | 8-10 | 11-2 | 13-7 | 15-9 | ||
| Douglas Fir-Larch | #2 | 6-1 | 8-11 | 11-3 | 13-9 | 15-11 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | ||
| Douglas Fir-Larch | #3 | 4-7 | 6-9 | 8-6 | 10-5 | 12-1 | 4-3 | 6-3 | 7-11 | 9-7 | 11-2 | ||
| Hem-Fir | SS | 6-10 | 10-9 | 14-2 | 17-5 | 20-2 | 6-10 | 10-5 | 13-2 | 16-1 | 18-8 | ||
| Hem-Fir | #1 | 6-4 | 9-3 | 11-9 | 14-4 | 16-7 | 5-10 | 8-7 | 10-10 | 13-3 | 15-5 | ||
| Hem-Fir | #2 | 6-0 | 8-9 | 11-1 | 13-7 | 15-9 | 5-7 | 8-1 | 10-3 | 12-7 | 14-7 | ||
| Hem-Fir | #3 | 4-7 | 6-9 | 8-6 | 10-5 | 12-1 | 4-3 | 6-3 | 7-11 | 9-7 | 11-2 | ||
| Southern Pine | SS | 7-1 | 11-2 | 14-8 | 18-9 | 22-10 | 7-1 | 11-2 | 14-8 | 18-7 | 21-9 | ||
| Southern Pine | #1 | 7-0 | 10-8 | 13-5 | 16-0 | 19-1 | 6-8 | 9-11 | 12-5 | 14-10 | 17-8 | ||
| Southern Pine | #2 | 6-6 | 9-4 | 12-0 | 14-4 | 16-10 | 6-0 | 8-8 | 11-2 | 13-4 | 15-7 | ||
| Southern Pine | #3 | 4-11 | 7-3 | 9-2 | 10-10 | 12-11 | 4-6 | 6-8 | 8-6 | 10-1 | 12-0 | ||
| Spruce-Pine-Fir | SS | 6-8 | 10-6 | 13-5 | 16-5 | 19-1 | 6-8 | 9-10 | 12-5 | 15-3 | 17-8 | ||
| Spruce-Pine-Fir | #1 | 6-1 | 8-11 | 11-3 | 13-9 | 15-11 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | ||
| Spruce-Pine-Fir | #2 | 6-1 | 8-11 | 11-3 | 13-9 | 15-11 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | ||
| Spruce-Pine-Fir | #3 | 4-7 | 6-9 | 8-6 | 10-5 | 12-1 | 4-3 | 6-3 | 7-11 | 9-7 | 11-2 | ||
| 24 | Douglas Fir-Larch | SS | 6-8 | 10-3 | 13-0 | 15-10 | 18-4 | 6-6 | 9-6 | 12-0 | 14-8 | 17-0 | |
| Douglas Fir-Larch | #1 | 5-10 | 8-6 | 10-9 | 13-2 | 15-3 | 5-5 | 7-10 | 10-0 | 12-2 | 14-1 | ||
| Douglas Fir-Larch | #2 | 5-5 | 7-11 | 10-1 | 12-4 | 14-3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | ||
| Douglas Fir-Larch | #3 | 4-1 | 6-0 | 7-7 | 9-4 | 10-9 | 3-10 | 5-7 | 7-1 | 8-7 | 10-0 | ||
| Hem-Fir | SS | 6-4 | 9-11 | 12-9 | 15-7 | 18-0 | 6-4 | 9-4 | 11-9 | 14-5 | 16-8 | ||
| Hem-Fir | #1 | 5-8 | 8-3 | 10-6 | 12-10 | 14-10 | 5-3 | 7-8 | 9-9 | 11-10 | 13-9 | ||
| Hem-Fir | #2 | 5-4 | 7-10 | 9-11 | 12-1 | 14-1 | 4-11 | 7-3 | 9-2 | 11-3 | 13-0 | ||
| Hem-Fir | #3 | 4-1 | 6-0 | 7-7 | 9-4 | 10-9 | 3-10 | 5-7 | 7-1 | 8-7 | 10-0 | ||
| Southern Pine | SS | 6-7 | 10-4 | 13-8 | 17-5 | 21-0 | 6-7 | 10-4 | 13-8 | 16-7 | 19-5 | ||
| Southern Pine | #1 | 6-5 | 9-7 | 12-0 | 14-4 | 17-1 | 6-0 | 8-10 | 11-2 | 13-3 | 15-9 | ||
| Southern Pine | #2 | 5-10 | 8-4 | 10-9 | 12-10 | 15-1 | 5-5 | 7-9 | 10-0 | 11-11 | 13-11 | ||
| Southern Pine | #3 | 4-4 | 6-5 | 8-3 | 9-9 | 11-7 | 4-1 | 6-0 | 7-7 | 9-0 | 10-8 | ||
| Spruce-Pine-Fir | SS | 6-2 | 9-6 | 12-0 | 14-8 | 17-1 | 6-0 | 8-10 | 11-2 | 13-7 | 15-9 | ||
| Spruce-Pine-Fir | #1 | 5-5 | 7-11 | 10-1 | 12-4 | 14-3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | ||
| Spruce-Pine-Fir | #2 | 5-5 | 7-11 | 10-1 | 12-4 | 14-3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | ||
| Spruce-Pine-Fir | #3 | 4-1 | 6-0 | 7-7 | 9-4 | 10-9 | 3-10 | 5-7 | 7-1 | 8-7 | 10-0 | ||
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
per square foot = 47.9 N/m2. a. Span exceeds 26 feet in length. Check sources for availability of lumber in lengths greater than 20 feet. |
TABLE 2308.10.3(5) RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground Snow Load = 30 pounds per square foot, Ceiling Attached to Rafters, L/[Delta] = 240)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 pounds psf | |||||||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | |||
| Maximum rafter spans | ||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 12 | Douglas Fir-Larch | SS | 9-1 | 14-4 | 18-10 | 24-1 | Note a | 9-1 | 14-4 | 18-10 | 24-1 | Note a |
| Douglas Fir-Larch | #1 | 8-9 | 13-9 | 18-2 | 22-9 | Note a | 8-9 | 13-2 | 16-8 | 20-4 | 23-7 | |
| Douglas Fir-Larch | #2 | 8-7 | 13-6 | 17-5 | 21-4 | 24-8 | 8-5 | 12-4 | 15-7 | 19-1 | 22-1 | |
| Douglas Fir-Larch | #3 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | 6-4 | 9-4 | 11-9 | 14-5 | 16-8 | |
| Hem-Fir | SS | 8-7 | 13-6 | 17-10 | 22-9 | Note a | 8-7 | 13-6 | 17-10 | 22-9 | Note a | |
| Hem-Fir | #1 | 8-5 | 13-3 | 17-5 | 22-2 | 25-9 | 8-5 | 12-10 | 16-3 | 19-10 | 23-0 | |
| Hem-Fir | #2 | 8-0 | 12-7 | 16-7 | 21-0 | 24-4 | 8-0 | 12-2 | 15-4 | 18-9 | 21-9 | |
| Hem-Fir | #3 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | 6-4 | 9-4 | 11-9 | 14-5 | 16-8 | |
| Southern Pine | SS | 8-11 | 14-1 | 18-6 | 23-8 | Note a | 8-11 | 14-1 | 18-6 | 23-8 | Note a | |
| Southern Pine | #1 | 8-9 | 13-9 | 18-2 | 23-2 | Note a | 8-9 | 13-9 | 18-2 | 22-2 | Note a | |
| Southern Pine | #2 | 8-7 | 13-6 | 17-10 | 22-3 | Note a | 8-7 | 12-11 | 16-8 | 19-11 | 23-4 | |
| Southern Pine | #3 | 7-7 | 11-2 | 14-3 | 16-10 | 20-0 | 6-9 | 10-0 | 12-9 | 15-1 | 17-11 | |
| Spruce-Pine-Fir | SS | 8-5 | 13-3 | 17-5 | 22-3 | Note a | 8-5 | 13-3 | 17-5 | 22-3 | Note a | |
| Spruce-Pine-Fir | #1 | 8-3 | 12-11 | 17-0 | 21-4 | 24-8 | 8-3 | 12-4 | 15-7 | 19-1 | 22-1 | |
| Spruce-Pine-Fir | #2 | 8-3 | 12-11 | 17-0 | 21-4 | 24-8 | 8-3 | 12-4 | 15-7 | 19-1 | 22-1 | |
| Spruce-Pine-Fir | #3 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | 6-4 | 9-4 | 11-9 | 14-5 | 16-8 | |
| 16 | Douglas Fir-Larch | SS | 8-3 | 13-0 | 17-2 | 21-10 | Note a | 8-3 | 13-0 | 17-2 | 21-3 | 24-8 |
| Douglas Fir-Larch | #1 | 8-0 | 12-6 | 16-2 | 19-9 | 22-10 | 7-10 | 11-5 | 14-5 | 17-8 | 20-5 | |
| Douglas Fir-Larch | #2 | 7-10 | 11-11 | 15-1 | 18-5 | 21-5 | 7-3 | 10-8 | 13-6 | 16-6 | 19-2 | |
| Douglas Fir-Larch | #3 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | 5-6 | 8-1 | 10-3 | 12-6 | 14-6 | |
| Hem-Fir | SS | 7-10 | 12-3 | 16-2 | 20-8 | 25-1 | 7-10 | 12-3 | 16-2 | 20-8 | 24-2 | |
| Hem-Fir | #1 | 7-8 | 12-0 | 15-9 | 19-3 | 22-3 | 7-7 | 11-1 | 14-1 | 17-2 | 19-11 | |
| Hem-Fir | #2 | 7-3 | 11-5 | 14-11 | 18-2 | 21-1 | 7-2 | 10-6 | 13-4 | 16-3 | 18-10 | |
| Hem-Fir | #3 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | 5-6 | 8-1 | 10-3 | 12-6 | 14-6 | |
| Southern Pine | SS | 8-1 | 12-9 | 16-10 | 21-6 | Note a | 8-1 | 12-9 | 16-10 | 21-6 | Note a | |
| Southern Pine | #1 | 8-0 | 12-6 | 16-6 | 21-1 | 25-7 | 8-0 | 12-6 | 16-2 | 19-2 | 22-10 | |
| Southern Pine | #2 | 7-10 | 12-3 | 16-2 | 19-3 | 22-7 | 7-10 | 11-2 | 14-5 | 17-3 | 20-2 | |
| Southern Pine | #3 | 6-7 | 9-8 | 12-4 | 14-7 | 17-4 | 5-10 | 8-8 | 11-0 | 13-0 | 15-6 | |
| Spruce-Pine-Fir | SS | 7-8 | 12-0 | 15-10 | 20-2 | 24-7 | 7-8 | 12-0 | 15-10 | 19-9 | 22-10 | |
| Spruce-Pine-Fir | #1 | 7-6 | 11-9 | 15-1 | 18-5 | 21-5 | 7-3 | 10-8 | 13-6 | 16-6 | 19-2 | |
| Spruce-Pine-Fi | #2 | 7-6 | 11-9 | 15-1 | 18-5 | 21-5 | 7-3 | 10-8 | 13-6 | 16-6 | 19-2 | |
| Spruce-Pine-Fi | #3 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | 5-6 | 8-1 | 10-3 | 12-6 | 14-6 | |
TABLE 2308.10.3(5)-continued RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground Snow Load = 30 pounds per square foot, Ceiling Attached to Rafters, L/[Delta] = 240)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 pounds psf | |||||||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 ×12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | |||
| Maximum rafter spans | ||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 19.2 | Douglas Fir-Larch | SS | 7-9 | 12-3 | 16-1 | 20-7 | 25-0 | 7-9 | 12-3 | 15-10 | 19-5 | 22-6 |
| Douglas Fir-Larch | #1 | 7-6 | 11-8 | 14-9 | 18-0 | 20-11 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | |
| Douglas Fir-Larch | #2 | 7-4 | 10-11 | 13-9 | 16-10 | 19-6 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | |
| Douglas Fir-Larch | #3 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | |
| Hem-Fir | SS | 7-4 | 11-7 | 15-3 | 19-5 | 23-7 | 7-4 | 11-7 | 15-3 | 19-1 | 22-1 | |
| Hem-Fir | #1 | 7-2 | 11-4 | 14-4 | 17-7 | 20-4 | 6-11 | 10-2 | 12-10 | 15-8 | 18-2 | |
| Hem-Fir | #2 | 6-10 | 10-9 | 13-7 | 16-7 | 19-3 | 6-7 | 9-7 | 12-2 | 14-10 | 17-3 | |
| Hem-Fir | #3 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | |
| Southern Pine | SS | 7-8 | 12-0 | 15-10 | 20-2 | 24-7 | 7-8 | 12-0 | 15-10 | 20-2 | 24-7 | |
| Southern Pine | #1 | 7-6 | 11-9 | 15-6 | 19-7 | 23-4 | 7-6 | 11-9 | 14-9 | 17-6 | 20-11 | |
| Southern Pine | #2 | 7-4 | 11-5 | 14-9 | 17-7 | 20-7 | 7-1 | 10-2 | 13-2 | 15-9 | 18-5 | |
| Southern Pine | #3 | 6-0 | 8-10 | 11-3 | 13-4 | 15-10 | 5-4 | 7-11 | 10-1 | 11-11 | 14-2 | |
| Spruce-Pine-Fir | SS | 7-2 | 11-4 | 14-11 | 19-0 | 23-1 | 7-2 | 11-4 | 14-9 | 18-0 | 20-11 | |
| Spruce-Pine-Fir | #1 | 7-0 | 10-11 | 13-9 | 16-10 | 19-6 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | |
| Spruce-Pine-Fir | #2 | 7-0 | 10-11 | 13-9 | 16-10 | 19-6 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | |
| Spruce-Pine-Fir | #3 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | |
| 24 | Douglas Fir-Larch | SS | 7-3 | 11-4 | 15-0 | 19-1 | 22-6 | 7-3 | 11-3 | 14-2 | 17-4 | 20-1 |
| Douglas Fir-Larch | #1 | 7-0 | 10-5 | 13-2 | 16-1 | 18-8 | 6-4 | 9-4 | 11-9 | 14-5 | 16-8 | |
| Douglas Fir-Larch | #2 | 6-8 | 9-9 | 12-4 | 15-1 | 17-6 | 5-11 | 8-8 | 11-0 | 13-6 | 15-7 | |
| Douglas Fir-Larch | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-6 | 6-7 | 8-4 | 10-2 | 11-10 | |
| Hem-Fir | SS | 6-10 | 10-9 | 14-2 | 18-0 | 21-11 | 6-10 | 10-9 | 13-11 | 17-0 | 19-9 | |
| Hem-Fir | #1 | 6-8 | 10-2 | 12-10 | 15-8 | 18-2 | 6-2 | 9-1 | 11-6 | 14-0 | 16-3 | |
| Hem-Fir | #2 | 6-4 | 9-7 | 12-2 | 14-10 | 17-3 | 5-10 | 8-7 | 10-10 | 13-3 | 15-5 | |
| Hem-Fir | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-6 | 6-7 | 8-4 | 10-2 | 11-10 | |
| Southern Pine | SS | 7-1 | 11-2 | 14-8 | 18-9 | 22-10 | 7-1 | 11-2 | 14-8 | 18-9 | 22-10 | |
| Southern Pine | #1 | 7-0 | 10-11 | 14-5 | 17-6 | 20-11 | 7-0 | 10-6 | 13-2 | 15-8 | 18-8 | |
| Southern Pine | #2 | 6-10 | 10-2 | 13-2 | 15-9 | 18-5 | 6-4 | 9-2 | 11-9 | 14-1 | 16-6 | |
| Southern Pine | #3 | 5-4 | 7-11 | 10-1 | 11-11 | 14-2 | 4-9 | 7-1 | 9-0 | 10-8 | 12-8 | |
| Spruce-Pine-Fir | SS | 6-8 | 10-6 | 13-10 | 17-8 | 20-11 | 6-8 | 10-5 | 13-2 | 16-1 | 18-8 | |
| Spruce-Pine-Fir | #1 | 6-6 | 9-9 | 12-4 | 15-1 | 17-6 | 5-11 | 8-8 | 11-0 | 13-6 | 15-7 | |
| Spruce-Pine-Fir | #2 | 6-6 | 9-9 | 12-4 | 15-1 | 17-6 | 5-11 | 8-8 | 11-0 | 13-6 | 15-7 | |
| Spruce-Pine-Fir | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-6 | 6-7 | 8-4 | 10-2 | 11-10 | |
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
per square foot = 47.9 N/m2. a. Span exceeds 26 feet in length. Check sources for availability of lumber in lengths greater than 20 feet. |
TABLE 2308.10.3(6) RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground Snow Load = 50 pounds per square foot, Ceiling Attached to Rafters, L/[Delta] = 240)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 pounds psf | |||||||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | |||
| Maximum rafter spans | ||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 12 | Douglas Fir-Larch | SS | 7-8 | 12-1 | 15-11 | 20-3 | 24-8 | 7-8 | 12-1 | 15-11 | 20-3 | 24-0 |
| Douglas Fir-Larch | #1 | 7-5 | 11-7 | 15-3 | 18-7 | 21-7 | 7-5 | 11-2 | 14-1 | 17-3 | 20-0 | |
| Douglas Fir-Larch | #2 | 7-3 | 11-3 | 14-3 | 17-5 | 20-2 | 7-1 | 10-5 | 13-2 | 16-1 | 18-8 | |
| Douglas Fir-Larch | #3 | 5-10 | 8-6 | 10-9 | 13-2 | 15-3 | 5-5 | 7-10 | 10-0 | 12-2 | 14-1 | |
| Hem-Fir | SS | 7-3 | 11-5 | 15-0 | 19-2 | 23-4 | 7-3 | 11-5 | 15-0 | 19-2 | 23-4 | |
| Hem-Fir | #1 | 7-1 | 11-2 | 14-8 | 18-1 | 21-0 | 7-1 | 10-10 | 13-9 | 16-9 | 19-5 | |
| Hem-Fir | #2 | 6-9 | 10-8 | 14-0 | 17-2 | 19-11 | 6-9 | 10-3 | 13-0 | 15-10 | 18-5 | |
| Hem-Fir | #3 | 5-10 | 8-6 | 10-9 | 13-2 | 15-3 | 5-5 | 7-10 | 10-0 | 12-2 | 14-1 | |
| Southern Pine | SS | 7-6 | 11-0 | 15-7 | 19-11 | 24-3 | 7-6 | 11-10 | 15-7 | 19-11 | 24-3 | |
| Southern Pine | #1 | 7-5 | 11-7 | 15-4 | 19-7 | 23-9 | 7-5 | 11-7 | 15-4 | 18-9 | 22-4 | |
| Southern Pine | #2 | 7-3 | 11-5 | 15-0 | 18-2 | 21-3 | 7-3 | 10-11 | 14-1 | 16-10 | 19-9 | |
| Southern Pine | #3 | 6-2 | 9-2 | 11-8 | 13-9 | 16-4 | 5-9 | 8-5 | 10-9 | 12-9 | 15-2 | |
| Spruce-Pine-Fir | SS | 7-1 | 11-2 | 14-8 | 18-9 | 22-10 | 7-1 | 11-2 | 14-8 | 18-9 | 22-4 | |
| Spruce-Pine-Fir | #1 | 6-11 | 10-11 | 14-3 | 17-5 | 20-2 | 6-11 | 10-5 | 13-2 | 16-1 | 18-8 | |
| Spruce-Pine-Fir | #2 | 6-11 | 10-11 | 14-3 | 17-5 | 20-2 | 6-11 | 10-5 | 13-2 | 16-1 | 18-8 | |
| Spruce-Pine-Fir | #3 | 5-10 | 8-6 | 10-9 | 13-2 | 15-3 | 5-5 | 7-10 | 10-0 | 12-2 | 14-1 | |
| 16 | Douglas Fir-Larch | SS | 7-0 | 11-0 | 14-5 | 18-5 | 22-5 | 7-0 | 11-0 | 14-5 | 17-11 | 20-10 |
| Douglas Fir-Larch | #1 | 6-9 | 10-5 | 13-2 | 16-1 | 18-8 | 6-7 | 9-8 | 12-2 | 14-11 | 17-3 | |
| Douglas Fir-Larch | #2 | 6-7 | 9-9 | 12-4 | 15-1 | 17-6 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | |
| Douglas Fir-Larch | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-8 | 6-10 | 8-8 | 10-6 | 12-3 | |
| Hem-Fir | SS | 6-7 | 10-4 | 13-8 | 17-5 | 21-2 | 6-7 | 10-4 | 13-8 | 17-5 | 20-5 | |
| Hem-Fir | #1 | 6-5 | 10-2 | 12-10 | 15-8 | 18-2 | 6-5 | 9-5 | 11-11 | 14-6 | 16-10 | |
| Hem-Fir | #2 | 6-2 | 9-7 | 12-2 | 14-10 | 17-3 | 6-1 | 8-11 | 11-3 | 13-9 | 15-11 | |
| Hem-Fir | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-8 | 6-10 | 8-8 | 10-6 | 12-3 | |
| Southern Pine | SS | 6-10 | 10-9 | 14-2 | 18-1 | 22-0 | 6-10 | 10-9 | 14-2 | 18-1 | 22-0 | |
| Southern Pine | #1 | 6-9 | 10-7 | 13-11 | 17-6 | 20-11 | 6-9 | 10-7 | 13-8 | 16-2 | 19-4 | |
| Southern Pine | #2 | 6-7 | 10-2 | 13-2 | 15-9 | 18-5 | 6-7 | 9-5 | 12-2 | 14-7 | 17-1 | |
| Southern Pine | #3 | 5-4 | 7-11 | 10-1 | 11-11 | 14-2 | 4-11 | 7-4 | 9-4 | 11-0 | 13-1 | |
| Spruce-Pine-Fir | SS | 6-5 | 10-2 | 13-4 | 17-0 | 20-9 | 6-5 | 10-2 | 13-4 | 16-8 | 19-4 | |
| Spruce-Pine-Fir | #1 | 6-4 | 9-9 | 12-4 | 15-1 | 17-6 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | |
| Spruce-Pine-Fir | #2 | 6-4 | 9-9 | 12-4 | 15-1 | 17-6 | 6-2 | 9-0 | 11-5 | 13-11 | 16-2 | |
| Spruce-Pine-Fir | #3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | 4-8 | 6-10 | 8-8 | 10-6 | 12-3 | |
TABLE 2308.10.3(6)-continued RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground Snow Load = 50 pounds per square foot, Ceiling Attached to Rafters, L/[Delta] = 240)
| RAFTER SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds psf | DEAD LOAD = 20 pounds psf | |||||||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | |||
| Maximum rafter spans | ||||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 19.2 | Douglas Fir-Larch | SS | 6-7 | 10-4 | 13-7 | 17-4 | 20-6 | 6-7 | 10-4 | 13-5 | 16-5 | 19-0 |
| Douglas Fir-Larch | #1 | 6-4 | 9-6 | 12-0 | 14-8 | 17-1 | 6-0 | 8-10 | 11-2 | 13-7 | 15-9 | |
| Douglas Fir-Larch | #2 | 6-1 | 8-11 | 11-3 | 13-9 | 15-11 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | |
| Douglas Fir-Larch | #3 | 4-7 | 6-9 | 8-6 | 10-5 | 12-1 | 4-3 | 6-3 | 7-11 | 9-7 | 11-2 | |
| Hem-Fir | SS | 6-2 | 9-9 | 12-10 | 16-5 | 19-11 | 6-2 | 9-9 | 12-10 | 16-1 | 18-8 | |
| Hem-Fir | #1 | 6-1 | 9-3 | 11-9 | 14-4 | 16-7 | 5-10 | 8-7 | 10-10 | 13-3 | 15-5 | |
| Hem-Fir | #2 | 5-9 | 8-9 | 11-1 | 13-7 | 15-9 | 5-7 | 8-1 | 10-3 | 12-7 | 14-7 | |
| Hem-Fir | #3 | 4-7 | 6-9 | 8-6 | 10-5 | 12-1 | 4-3 | 6-3 | 7-11 | 9-7 | 11-2 | |
| Southern Pine | SS | 6-5 | 10-2 | 13-4 | 17-0 | 20-9 | 6-5 | 10-2 | 13-4 | 17-0 | 20-9 | |
| Southern Pine | #1 | 6-4 | 9-11 | 13-1 | 16-0 | 19-1 | 6-4 | 9-11 | 12-5 | 14-10 | 17-8 | |
| Southern Pine | #2 | 6-2 | 9-4 | 12-0 | 14-4 | 16-10 | 6-0 | 8-8 | 11-2 | 13-4 | 15-7 | |
| Southern Pine | #3 | 4-11 | 7-3 | 9-2 | 10-10 | 12-11 | 4-6 | 6-8 | 8-6 | 10-1 | 12-0 | |
| Spruce-Pine-Fir | SS | 6-1 | 9-6 | 12-7 | 16-0 | 19-1 | 6-1 | 9-6 | 12-5 | 15-3 | 17-8 | |
| Spruce-Pine-Fir | #1 | 5-11 | 8-11 | 11-3 | 13-9 | 15-11 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | |
| Spruce-Pine-Fir | #2 | 5-11 | 8-11 | 11-3 | 13-9 | 15-11 | 5-7 | 8-3 | 10-5 | 12-9 | 14-9 | |
| Spruce-Pine-Fir | #3 | 4-7 | 6-9 | 8-6 | 10-5 | 12-1 | 4-3 | 6-3 | 7-11 | 9-7 | 11-2 | |
| 24 | Douglas Fir-Larch | SS | 6-1 | 9-7 | 12-7 | 15-10 | 18-4 | 6-1 | 9-6 | 12-0 | 14-8 | 17-0 |
| Douglas Fir-Larch | #1 | 5-10 | 8-6 | 10-9 | 13-2 | 15-3 | 5-5 | 7-10 | 10-0 | 12-2 | 14-1 | |
|
Douglas Fire-Larch |
#2 | 5-5 | 7-11 | 10-1 | 12-4 | 14-3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | |
|
Douglas Fir-Larch |
#3 | 4-1 | 6-0 | 7-7 | 9-4 | 10-9 | 3-10 | 5-7 | 7-1 | 8-7 | 10-0 | |
|
Hem-Fir |
SS | 5-9 | 9-1 | 11-11 | 15-12 | 18-0 | 5-9 | 9-1 | 11-9 | 14-5 | 16-8 | |
|
Hem-Fir |
#1 | 5-8 | 8-3 | 10-6 | 12-10 | 14-10 | 5-3 | 7-8 | 9-9 | 11-10 | 13-9 | |
|
Hem-Fir |
#2 | 5-4 | 7-10 | 9-11 | 12-1 | 14-1 | 4-11 | 7-3 | 9-2 | 11-3 | 13-0 | |
|
Hem-Fir |
#3 | 4-1 | 6-0 | 7-7 | 9-4 | 10-9 | 3-10 | 5-7 | 7-1 | 8-7 | 10-0 | |
|
Southern Pine |
SS | 6-0 | 9-5 | 12-5 | 15-10 | 19-3 | 6-0 | 9-5 | 12-5 | 15-10 | 19-3 | |
|
Southern Pine |
#1 | 5-10 | 9-3 | 12-0 | 14-4 | 17-1 | 5-10 | 8-10 | 11-2 | 13-3 | 15-9 | |
|
Southern Pine |
#2 | 5-9 | 8-4 | 10-9 | 12-10 | 15-1 | 5-5 | 7-9 | 10-0 | 11-11 | 13-11 | |
|
Southern Pine |
#3 | 4-4 | 6-5 | 8-3 | 9-9 | 11-7 | 4-1 | 6-0 | 7-7 | 9-0 | 10-8 | |
|
Spruce-Pine-Fir |
SS | 5-8 | 8-10 | 11-8 | 14-8 | 17-1 | 5-8 | 8-10 | 11-2 | 13-7 | 15-9 | |
|
Spruce-Pine-Fir |
#1 | 5-5 | 7-11 | 10-1 | 12-4 | 14-3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | |
| Spruce-Pine-Fir | #2 | 5-5 | 7-11 | 10-1 | 12-4 | 14-3 | 5-0 | 7-4 | 9-4 | 11-5 | 13-2 | |
| Spruce-Pine-Fir | #3 | 4-1 | 6-0 | 7-7 | 9-4 | 10-9 | 3-10 | 5-7 | 7-1 | 8-7 | 10-0 | |
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 47.9 N/m2. |
2308.10.4 Ceiling joist and rafter framing. Rafters shall be framed directly opposite each other at the ridge. There shall be a ridge board at least 1-inch (25 mm) nominal thickness at ridges and not less in depth than the cut end of the rafter. At valleys and hips, there shall be a single valley or hip rafter not less than 2-inch (51 mm) nominal thickness and not less in depth than the cut end of the rafter.
2308.10.4.1
Ceiling joist and rafter
connections. Ceiling joists and rafters shall be nailed to each other
and the assembly shall be nailed to the top wall plate in accordance with
Tables 2304.9.1 and 2308.10.1. Ceiling joists shall be continuous or securely
joined where they meet over interior partitions and fastened to adjacent
rafters in accordance with Tables 2308.10.4.1 and 2304.9.1 to provide a
continuous rafter tie across the building where such joists are parallel to the
rafters. Ceiling joists shall have a bearing surface of not less than
11/2 inches (38 mm) on the
top plate at each end.
Where ceiling joists are not parallel to rafters, an equivalent rafter tie shall be installed in a manner to provide a continuous tie across the building, at a spacing of not more than 4 feet (1219 mm) o.c. The connections shall be in accordance with Tables 2308.10.4.1 and 2304.9.1, or connections of equivalent capacities shall be provided. Where ceiling joists or rafter ties are not provided at the top of the rafter support walls, the ridge formed by these rafters shall also be supported by a girder conforming to Section 2308.4.
Rafter ties shall be spaced not more than 4 feet (1219 mm) o.c. Rafter tie connections shall be based on the equivalent rafter spacing in Table 2308.10.4.1. Where rafter ties are spaced at 32 inches (813 mm) o.c., the number of 16d common nails shall be two times the number specified for rafters spaced 16 inches (406 mm) o.c., with a minimum of four 16d common nails where no snow loads are indicated. Where rafter ties are spaced at 48 inches (1219 mm) o.c., the number of 16d common nails shall be two times the number specified for rafters spaced 24 inches (610 mm) o.c., with a minimum of six 16d common nails where no snow loads are indicated. Rafter/ceiling joist connections and rafter/tie connections shall be of sufficient size and number to prevent splitting from nailing.
TABLE 2308.10.4.1 RAFTER TIE CONNECTIONSg
| RAFTER SLOPE | TIE SPACING (inches) | NO SNOW LOAD | GROUND SNOW LOAD (pound per square foot) | ||||||||||
| 30 pounds per square foot | 50 pounds per square foot | ||||||||||||
| Roof span (feet) | |||||||||||||
| 12 | 20 | 28 | 36 | 12 | 20 | 28 | 36 | 12 | 20 | 28 | 36 | ||
| Required number of 16d common (31/2" x 0.162") nailsa, b per connectionc, d, e, f | |||||||||||||
| 3:12 | 12 | 4 | 6 | 8 | 10 | 4 | 6 | 8 | 11 | 5 | 8 | 12 | 15 |
| 16 | 5 | 7 | 10 | 13 | 5 | 8 | 11 | 14 | 6 | 11 | 15 | 20 | |
| 24 | 7 | 11 | 15 | 19 | 7 | 11 | 16 | 21 | 9 | 16 | 23 | 30 | |
| 32 | 10 | 14 | 19 | 25 | 10 | 16 | 22 | 28 | 12 | 27 | 30 | 40 | |
| 48 | 14 | 21 | 29 | 37 | 14 | 32 | 36 | 42 | 18 | 32 | 46 | 60 | |
| 4:12 | 12 | 3 | 4 | 5 | 6 | 3 | 5 | 6 | 8 | 4 | 6 | 9 | 11 |
| 16 | 3 | 5 | 7 | 8 | 4 | 6 | 8 | 11 | 5 | 8 | 12 | 15 | |
| 24 | 4 | 7 | 10 | 12 | 5 | 9 | 12 | 16 | 7 | 12 | 17 | 22 | |
| 32 | 6 | 9 | 13 | 16 | 8 | 12 | 16 | 22 | 10 | 16 | 24 | 30 | |
| 48 | 8 | 14 | 19 | 24 | 10 | 18 | 24 | 32 | 14 | 24 | 34 | 44 | |
| 5:12 | 12 | 3 | 3 | 4 | 5 | 3 | 4 | 5 | 7 | 3 | 5 | 7 | 9 |
| 16 | 3 | 4 | 5 | 7 | 3 | 5 | 7 | 9 | 4 | 7 | 9 | 12 | |
| 24 | 4 | 6 | 8 | 10 | 4 | 7 | 10 | 13 | 6 | 10 | 14 | 18 | |
| 32 | 5 | 8 | 10 | 13 | 6 | 10 | 14 | 18 | 8 | 14 | 18 | 24 | |
| 48 | 7 | 11 | 15 | 20 | 8 | 14 | 20 | 26 | 12 | 20 | 28 | 36 | |
| 7:12 | 12 | 3 | 3 | 3 | 4 | 3 | 3 | 4 | 5 | 3 | 4 | 5 | 7 |
| 16 | 3 | 3 | 4 | 5 | 3 | 4 | 5 | 6 | 3 | 5 | 7 | 9 | |
| 24 | 3 | 4 | 6 | 7 | 3 | 5 | 7 | 9 | 4 | 7 | 10 | 13 | |
| 32 | 4 | 6 | 8 | 10 | 4 | 8 | 10 | 12 | 6 | 10 | 14 | 18 | |
| 48 | 5 | 8 | 11 | 14 | 6 | 10 | 14 | 18 | 9 | 14 | 20 | 26 | |
| 9:12 | 12 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 4 | 3 | 3 | 4 | 5 |
| 16 | 3 | 3 | 3 | 4 | 3 | 3 | 4 | 5 | 3 | 4 | 5 | 7 | |
| 24 | 3 | 3 | 5 | 6 | 3 | 4 | 6 | 7 | 3 | 6 | 8 | 10 | |
| 32 | 3 | 4 | 6 | 8 | 4 | 6 | 8 | 10 | 5 | 8 | 10 | 14 | |
| 48 | 4 | 6 | 9 | 11 | 5 | 8 | 12 | 14 | 7 | 12 | 16 | 20 | |
| 12:12 | 12 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 4 |
| 16 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 4 | 3 | 3 | 4 | 5 | |
| 24 | 3 | 3 | 3 | 4 | 3 | 3 | 4 | 6 | 3 | 4 | 6 | 8 | |
| 32 | 3 | 3 | 4 | 5 | 3 | 5 | 6 | 8 | 4 | 6 | 8 | 10 | |
| 48 | 3 | 4 | 6 | 7 | 4 | 7 | 8 | 12 | 6 | 8 | 12 | 16 | |
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
per square foot = 47.8 N/m2. a. 40d box (5" * 0.162") or l6d sinker (31/4" * 0.148") nails are permitted to be substituted for 16d common (31/2" * 0.16") nails. b. Nailing requirements are permitted to be reduced 25 percent if nails are clinched. c. Rafter tie heel joint connections are not required where the ridge is supported by a load-bearing wall, header or ridge beam. d. When intermediate support of the rafter is provided by vertical struts or purlins to a load-bearing wall, the tabulated heel joint connection requirements are permitted to be reduced proportionally to the reduction in span. e. Equivalent nailing patterns are required for ceiling joist to ceiling joist lap splices. f. Connected members shall be of sufficient size to prevent splitting due to nailing. g. For snow loads less than 30 pounds per square foot, the required number of nails is permitted to be reduced by multiplying by the ratio of actual snow load plus 10 divided by 40, but not less than the number required for no snow load. |
2308.10.4.2
Notches and holes.
Notching at the ends of rafters or ceiling joists shall not exceed one-fourth
the depth. Notches in the top or bottom of the rafter or ceiling joist shall
not exceed one-sixth the depth and shall not be located in the middle one-third
of the span, except that a notch not exceeding one-third of the depth is
permitted in the top of the rafter or ceiling joist not further from the face
of the support than the depth of the member.
Holes bored in rafters or ceiling joists shall not be within 2 inches (51 mm) of the top and bottom and their diameter shall not exceed one-third the depth of the member.
2308.10.4.3
Framing around
openings. Trimmer and header rafters shall be doubled, or of lumber of
equivalent cross section, where the span of the header exceeds 4 feet (1219
mm). The ends of header rafters more than 6 feet (1829 mm) long shall be
supported by framing anchors or rafter hangers unless bearing on a beam,
partition or wall.
2308.10.5 Purlins. Purlins to support roof loads are permitted to be installed to reduce the span of rafters within allowable limits and shall be supported by struts to bearing walls. The maximum span of 2-inch by 4-inch (51 mm by 102 mm) purlins shall be 4 feet (1219 mm). The maximum span of the 2-inch by 6-inch (51 mm by 152 mm) purlin shall be 6 feet (1829 mm), but in no case shall the purlin be smaller than the supported rafter. Struts shall not be smaller than 2-inch by 4-inch (51 mm by 102 mm) members. The unbraced length of struts shall not exceed 8 feet (2438 mm) and the minimum slope of the struts shall not be less than 45 degrees (0.79 rad) from the horizontal.
2308.10.6 Blocking. Roof rafters and ceiling joists shall be supported laterally to prevent rotation and lateral displacement in accordance with the provisions of Section 2308.8.5.
2308.10.7 Engineered wood products. Prefabricated wood I-joists, structural glued-laminated timber and structural composite lumber shall not be notched or drilled except where permitted by the manufacturer's recommendations or where the effects of such alterations are specifically considered in the design of the member by a registered design professional.
2308.10.8 Roof sheathing. Roof sheathing shall be in accordance with Tables 2304.7(3) and 2304.7(5) for wood structural panels, and Tables 2304.7(1) and 2304.7(2) for lumber and shall comply with Section 2304.7.2.
2308.10.8.1
Joints. Joints in lumber sheathing shall occur over supports
unless approved end-matched lumber is used, in which case each
piece shall bear on at least two supports.
2308.10.9 Roof planking. Planking shall be designed in accordance with the general provisions of this code.
In lieu of such design, 2-inch (51 mm) tongue-and- groove planking is permitted in accordance with Table 2308.10.9. Joints in such planking are permitted to be randomly spaced, provided the system is applied to not less than three continuous spans, planks are center matched and end matched or splined, each plank bears on at least one support, and joints are separated by at least 24 inches (610 mm) in adjacent pieces.
TABLE 2308.10.9 ALLOWABLE SPANS FOR 2-INCH TONGUE-AND-GROOVE DECKING
| SPANa (feet) | LIVE LOAD (pound per square foot) | DEFLECTION LIMIT | BENDING STRESS (f) (pound per square inch) | MODULUS OF ELASTICITY (E) (pound per square inch) |
| Roofs | ||||
| 4 | 20 | 1/240 1/360 | 160 | 170,000 256,000 |
| 30 | 1/240 1/360 | 210 | 256,000 384,000 | |
| 40 | 1/240 1/360 | 270 | 340,000 512,000 | |
| 4.5 | 20 | 1/240 1/360 | 200 | 242,000 305,000 |
| 30 | 1/240 1/360 | 270 | 363,000 405,000 | |
| 40 | 1/240 1/360 | 350 | 484,000 725,000 | |
| 5.0 | 20 | 1/240 1/360 | 250 | 332,000 500,000 |
| 30 | 1/240 1/360 | 330 | 495,000 742,000 | |
| 40 | 1/240 1/360 | 420 | 660,000 1,000,000 | |
| 5.5 | 20 | 1/240 1/360 | 300 | 442,000 660,000 |
| 30 | 1/240 1/360 | 400 | 662,000 998,000 | |
| 40 | 1/240 1/360 | 500 | 884,000 1,330,000 | |
| 6.0 | 20 | 1/240 1/360 | 360 | 575,000 862,000 |
| 30 | 1/240 1/360 | 480 | 862,000 1,295,000 | |
| 40 | 1/240 1/360 | 600 | 1,150,000 1,730,000 | |
| 6.5 | 20 | 1/240 1/360 | 420 | 595,000 892,000 |
| 30 | 1/240 1/360 | 560 | 892,000 1,340,000 | |
| 40 | 1/240 1/360 | 700 | 1,190,000 1,730,000 | |
TABLE 2308.10.9-continued ALLOWABLE SPANS FOR 2-INCH TONGUE-AND-GROOVE DECKING
| SPANa (feet) | LIVE LOAD (pound per square foot) | DEFLECTION LIMIT | BENDING STRESS (f) (pound per square inch) | MODULUS OF ELASTICITY (E) (pound per square inch) |
| Roofs | ||||
| 7.0 | 20 | 1/240 1/360 | 490 | 910,000 1,360,000 |
| 30 | 1/240 1/360 | 650 | 1,370,000 2,000,000 | |
| 40 | 1/240 1/360 | 810 | 1,820,000 2,725,000 | |
| 7.5 | 20 | 1/240 1/360 | 560 | 1,125,000 1,685,000 |
| 30 | 1/240 1/360 | 750 | 1,685,000 2,530,000 | |
| 40 | 1/240 1/360 | 930 | 2,250,000 3,380,000 | |
| 8.0 | 20 | 1/240 1/360 | 640 | 1,360,000 2,040,000 |
| 30 | 1/240 1/360 | 850 | 2,040,000 3,060,000 | |
| Floors | ||||
| 4 4.5 5.0 | 40 | 1/360 | 840 950 1,060 | 1,000,000 1,300,000 1,600,000 |
| For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
per square foot = 0.0479 kN/m2, 1 pound per square
inch = 0.00689 N/mm2. a. Spans are based on simple beam action with 10 pounds per square foot dead load and provisions for a 300-pound concentrated load on a 12-inch width of decking. Random layup is permitted in accordance with the provisions of Section 2308.10.9. Lumber thickness is 11/2 inches nominal. |
2308.10.10 Wood trusses. Wood trusses shall be designed in accordance with Section 2303.4.
2308.10.11 Attic ventilation. For attic ventilation, see Section 1203.2.
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