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

Current through Register 1525, July 5, 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.