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.
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
| NOMINAL DESIGN WIND SPEED,Vasdi | 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/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 28.6.3 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 Vasd 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.
i. Vasd shall be determined in accordance with Section 1609.3.1.
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 psf, L/Δ = 240)
| CEILING JOIST SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 5 pounds per square foot | ||||
| 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 | 26-0 | 26-0 |
| Douglas Fir-Larch | #1 | 12-8 | 19-11 | 26-0 | 26-0 | |
| Douglas Fir-Larch | #2 | 12-5 | 19-6 | 25-8 | 26-0 | |
| Douglas Fir-Larch | #3 | 10-10 | 15-10 | 20-1 | 24-6 | |
| Hem-Fir | SS | 12-5 | 19-6 | 25-8 | 26-0 | |
| Hem-Fir | #1 | 12-2 | 19-1 | 25-2 | 26-0 | |
| Hem-Fir | #2 | 11-7 | 18-2 | 24-0 | 26-0 | |
| Hem-Fir | #3 | 10-10 | 15-10 | 20-1 | 24-6 | |
| Southern Pine | SS | 12-11 | 20-3 | 26-0 | 26-0 | |
| Southern Pine | #1 | 12-8 | 19-11 | 26-0 | 26-0 | |
| Southern Pine | #2 | 12-5 | 19-6 | 25-8 | 26-0 | |
| Southern Pine | #3 | 11-6 | 17-0 | 21-8 | 25-7 | |
| Spruce-Pine-Fir | SS | 12-2 | 19-1 | 25-2 | 26-0 | |
| Spruce-Pine-Fir | #1 | 11-10 | 18-8 | 24-7 | 26-0 | |
| Spruce-Pine-Fir | #2 | 11-10 | 18-8 | 24-7 | 26-0 | |
| Spruce-Pine-Fir | #3 | 10-10 | 15-10 | 20-1 | 24-6 | |
| 16 | Douglas Fir-Larch | SS | 11-11 | 18-9 | 24-8 | 26-0 |
| Douglas Fir-Larch | #1 | 11-6 | 18-1 | 23-10 | 26-0 | |
| Douglas Fir-Larch | #2 | 11-3 | 17-8 | 23-0 | 26-0 | |
| Douglas Fir-Larch | #3 | 9-5 | 13-9 | 17-5 | 21-3 | |
| Hem-Fir | SS | 11-3 | 17-8 | 23-4 | 26-0 | |
| Hem-Fir | #1 | 11-0 | 17-4 | 22-10 | 26-0 | |
| Hem-Fir | #2 | 10-6 | 16-6 | 21-9 | 26-0 | |
| Hem-Fir | #3 | 9-5 | 13-9 | 17-5 | 21-3 | |
| Southern Pine | SS | 11-9 | 18-5 | 24-3 | 26-0 | |
| Southern Pine | #1 | 11-6 | 18-1 | 23-1 | 26-0 | |
| Southern Pine | #2 | 11-3 | 17-8 | 23-4 | 26-0 | |
| Southern Pine | #3 | 10-0 | 14-9 | 18-9 | 22-2 | |
| Spruce-Pine-Fir | SS | 11-0 | 17-4 | 22-10 | 26-0 | |
| Spruce-Pine-Fir | #1 | 10-9 | 16-11 | 22-4 | 26-0 | |
| Spruce-Pine-Fir | #2 | 10-9 | 16-11 | 22-4 | 26-0 | |
| Spruce-Pine-Fir | #3 | 9-5 | 13-9 | 17-5 | 21-3 | |
(continued)
TABLE 2308.10.2(1)—continued
CEILING JOIST SPANS FOR COMMON LUMBER SPECIES
(Uninhabitable Attics Without Storage, Live Load = 10 pounds psf, L/Δ = 240)
| CEILING JOIST SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 5 pounds per square foot | ||||
| 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 | 26-0 |
| Douglas Fir-Larch | #1 | 10-10 | 17-0 | 22-5 | 26-0 | |
| 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 | 26-0 | |
| Hem-Fir | #1 | 10-4 | 16-4 | 21-6 | 26-0 | |
| 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 | 26-0 | |
| Southern Pine | #1 | 10-10 | 17-0 | 22-5 | 26-0 | |
| Southern Pine | #2 | 10-7 | 16-8 | 21-11 | 26-0 | |
| Southern Pine | #3 | 9-1 | 13-6 | 17-2 | 20-3 | |
| Spruce-Pine-Fir | SS | 10-4 | 16-4 | 21-6 | 26-0 | |
| 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 | 26-0 |
| 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 | 26-0 | |
| 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 | 26-0 | |
| Southern Pine | #1 | 10-0 | 15-9 | 20-10 | 26-0 | |
| 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.
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/Δ = 240)
| CEILING JOIST SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds per square foot | ||||
| 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 | 26-0 |
| 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 | 26-0 | |
| 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 | 26-0 | |
| Southern Pine | #1 | 10-0 | 15-9 | 20-10 | 26-0 | |
| 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 | |
(continued)
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/Δ = 240)
| CEILING JOIST SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 pounds per square foot | ||||
| 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.