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.
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. |
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. |
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. |
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. |
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.
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. |
780 CMR, 2308.10