GroundRules
N.Y.C. Admin. Code § BC 2308: Section BC 2308: Conventional Light-Frame Construction
Where this section sits in the code
- New York City Administrative Code
- Title 28
- Chapter 7: New York City Building Code
2308.1 General.
The requirements of this section are intended for conventional light-frame construction. Other construction methods are permitted to be used, provided a satisfactory design is submitted showing compliance with other provisions of this code. Interior nonload-bearing partitions, ceilings and curtain walls of conventional light-frame construction are not subject to the limitations of Section 2308.2.
2308.1.1 Portions exceeding limitations of conventional light-frame construction.
When portions of a building of otherwise conventional light-frame construction exceed the limits of Section 2308.2, those portions and the supporting load path shall be designed in accordance with accepted engineering practice and the provisions of this code. For the purposes of this section, the term "portions" shall mean parts of buildings containing volume and area such as a room or a series of rooms. The extent of such design need only demonstrate compliance of the nonconventional light-framed elements with other applicable provisions of this code and shall be compatible with the performance of the conventional light-framed system.
2308.1.2 Connectors and fasteners.
Connectors and fasteners used in conventional light-frame construction shall comply with the requirements of Section 2304.10.
2308.2 Limitations.
Buildings are permitted to be constructed in accordance with the provisions of conventional light-frame construction, subject to the limitations in Sections 2308.2.1 through 2308.2.6.
2308.2.1 Stories.
Structures of conventional light-frame construction shall be limited in story height in accordance with Table 2308.2.1.
Table 2308.2.1 Allowable Story Height
Seismic Design Category
Allowable Story Above Grade Plane
A and B
Three stories
C
Two stories
D
a
One story
For SI: 1 inch = 25.4 mm.
a. For the purposes of this section, for buildings assigned to Seismic Design Category D cripple walls shall be considered to be a story unless cripple walls are solid blocked and do not exceed 14 inches in height.
2308.2.2 Allowable floor-to-floor height.
Maximum floor-to-floor height shall not exceed 11 feet, 7 inches (3531 mm). Exterior bearing wall and interior braced wall heights shall not exceed a stud height of 10 feet (3048 mm).
2308.2.3 Allowable loads.
Loads shall be in accordance with Chapter 16 and shall not exceed the following:
1. Average dead loads shall not exceed 15 psf (718 N/m
2
) for combined roof and ceiling, exterior walls, floors and partitions.
Exceptions:
1. Subject to the limitations of Section 2308.6.10, stone or masonry veneer up to the lesser of 5 inches (127 mm) thick or 50 psf (2395 N/m
2
) and installed in accordance with Chapter 14 is permitted to a height of 30 feet (9144 mm) above a noncombustible foundation, with an additional 8 feet (2438 mm) permitted for gable ends.
2. Concrete or masonry fireplaces, heaters and chimneys shall be permitted in accordance with the provisions of this code.
2. Live loads shall not exceed 40 psf (1916 N/m
2
) for floors.
Exception: Live loads for concrete slab-on-ground floors in Risk Categories I and II shall be not more than 125 psf.
2308.2.4 Basic design wind speed.
The basic design wind speed, V, in miles per hour for determination of wind loads shall be as set forth in Table 1609.3. Values are ultimate design 3-second gust wind speeds in miles per hour at 33 feet (10 058 mm) above ground Exposure Category C.
2308.2.5 Allowable roof span.
Ceiling joist and rafter framing constructed in accordance with Section 2308.7 and trusses shall not span more than 40 feet (12 192 mm) between points of vertical support. A ridge board in accordance with Section 2308.7 or 2308.7.3.1 shall not be considered a vertical support.
2308.2.6 Risk category limitation.
The use of the provisions for conventional light-frame construction in this section shall not be permitted for Risk Category IV buildings assigned to Seismic Design Category B, C, or D, as determined in Section 1613.
2308.3 Foundations and footings.
Foundations and footings shall be designed and constructed in accordance with Chapter 18. Connections to foundations and footings shall comply with this section.
2308.3.1 Foundation plates or sills.
Foundation plates or sills resting on concrete or masonry foundations shall comply with Section 2304.3.1. Foundation plates or sills shall be bolted or anchored to the foundation with not less than 1/2-inch-diameter (12.7 mm) steel bolts or approved anchors suitable for use with pressure-treated plates spaced to provide equivalent anchorage as the steel bolts. Bolts shall be embedded not less than 7 inches (178 mm) into concrete or masonry. The bolts shall be located in the middle third of the width of the plate. Bolts shall be spaced not more than 6 feet (1829 mm) on center and there shall be not less than two bolts or anchor straps per piece with one bolt or anchor strap located not more than 12 inches (305 mm) or less than 4 inches (102 mm) from each end of each piece. Bolts in sill plates of braced wall lines in structures over two stories above grade shall be spaced not more than 4 feet (1219 mm) on center. A properly sized nut and washer shall be tightened on each bolt to the plate.
2308.3.2 Braced wall line sill plate anchorage in Seismic Design Category D.
Sill plates along braced wall lines in buildings assigned to Seismic Design Category D shall be anchored with anchor bolts with steel plate washers between the foundation sill plate and the nut, or approved anchor straps load-rated in accordance with Section 2304.10.3. Such washers shall be a minimum of 0.229 inch by 3 inches by 3 inches (5.82 mm by 76 mm by 76 mm) in size. The hole in the plate washer is permitted to be diagonally slotted with a width of up to 3/16 inch (4.76 mm) larger than the bolt diameter and a slot length not to exceed 1 3/4 inches (44 mm), provided a standard cut washer is placed between the plate washer and the nut. All steel shall be of appropriate corrosion resistance when in contact with pressure-treated wood.
2308.4 Floor framing.
Floor framing shall comply with this section.
2308.4.1 Girders.
Girders for single-story construction or girders supporting loads from a single floor shall be not less than 4 inches by 6 inches (102 mm by 152 mm) for spans 6 feet (1829 mm) or less, provided that girders are spaced not more than 8 feet (2438 mm) on center. Other girders shall be designed to support the loads specified in this code. Girder end joints shall occur over supports.
Where a girder is spliced over a support, an adequate tie shall be provided. The ends of beams or girders supported on masonry or concrete shall not have less than 3 inches (76 mm) of bearing.
2308.4.1.1 Allowable girder spans.
The allowable spans of girders that are fabricated of dimension lumber shall not exceed the values set forth in Table 2308.4.1.1(1) or 2308.4.1.1(2).
Table 2308.4.1.1(1) Header and Girder Spans
a, b, c, d
for Exterior Bearing Walls (Maximum spans for Douglas Fir-Larch, Hem-Fir, Southern Pine and Spruce-Pine-Fir and required number of jack studs)
Headers and Girders Supporting
Size
Building width
e
(feet)
12
24
36
Span
g
NJ
f
Span
g
NJ
f
Span
g
NJ
f
Roof and ceiling
2-2 x 4
4-0
1
3-1
1
2-7
1
2-2 x 6
6-0
1
4-7
1
3-10
1
2-2 x 8
7-7
1
5-9
1
4-10
2
2-2 x 10
9-0
1
6-10
2
5-9
2
2-2 x 12
10-7
2
8-1
2
6-10
2
3-2 x 8
9-5
1
7-3
1
6-1
1
3-2 x 10
11-3
1
8-7
1
7-3
2
3-2 x 12
13-2
1
10-1
2
8-6
2
4-2 x 8
10-11
1
8-4
1
7-0
1
4-2 x 10
12-11
1
9-11
1
8-4
1
4-2 x 12
15-3
1
11-8
1
9-10
2
Roof, ceiling and one center-bearing floor
2-2 x 4
3-3
1
2-6
1
2-2
1
2-2 x 6
4-10
1
3-9
1
3-3
2
2-2 x 8
6-1
1
4-10
2
4-1
2
2-2 x 10
7-3
2
5-8
2
4-10
2
2-2 x 12
8-6
2
6-8
2
5-8
2
3-2 x 8
7-8
1
6-0
1
5-1
2
3-2 x 10
9-1
1
7-2
2
6-1
2
3-2 x 12
10-8
2
8-5
2
7-2
2
4-2 x 8
8-10
1
6-11
1
5-11
1
4-2 x 10
10-6
1
8-3
2
7-0
2
4-2 x 12
12-4
1
9-8
2
8-3
2
Roof, ceiling and one clear span floor
2-2 x 4
2-11
1
2-3
1
1-10
1
2-2 x 6
4-4
1
3-4
2
2-10
2
2-2 x 8
5-6
2
4-3
2
3-7
2
2-2 x 10
6-7
2
5-0
2
4-2
2
2-2 x 12
7-9
2
5-11
2
4-11
3
3-2 x 8
6-11
1
5-3
2
4-5
2
3-2 x 10
8-3
2
6-3
2
5-3
2
3-2 x 12
9-8
2
7-5
2
6-2
2
4-2 x 8
8-0
1
6-1
1
5-1
2
4-2 x 10
9-6
1
7-3
2
6-1
2
4-2 x 12
11-2
2
8-6
2
7-2
2
Roof, ceiling and two center-bearing floors
2-2 x 4
2-8
1
2-1
1
1-9
1
2-2 x 6
4-0
1
3-2
2
2-8
2
2-2 x 8
5-0
2
4-0
2
3-5
2
2-2 x 10
6-0
2
4-9
2
4-0
2
2-2 x 12
7-0
2
5-7
2
4-9
3
3-2 x 8
6-4
1
5-0
2
4-3
2
3-2 x 10
7-6
2
5-11
2
5-1
2
3-2 x 12
8-10
2
7-0
2
5-11
2
4-2 x 8
7-3
1
5-9
1
4-11
2
4-2 x 10
8-8
1
6-10
2
5-10
2
4-2 x 12
10-2
2
8-1
2
6-10
2
Roof, ceiling and two clear span floors
2-2 x 4
2-3
1
1-8
1
1-4
1
2-2 x 6
3-4
1
2-6
2
2-2
2
2-2 x 8
4-3
2
3-3
2
2-8
2
2-2 x 10
5-0
2
3-10
2
3-2
3
2-2 x 12
5-11
2
4-6
3
3-9
3
3-2 x 8
5-3
1
4-0
2
3-5
2
3-2 x 10
6-3
2
4-9
2
4-0
2
3-2 x 12
7-5
2
5-8
2
4-9
3
4-2 x 8
6-1
1
4-8
2
3-11
2
4-2 x 10
7-3
2
5-6
2
4-8
2
4-2 x 12
8-6
2
6-6
2
5-6
2
For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa.
a. Spans are given in feet and inches.
b. Spans are based on minimum design properties for No. 2 grade lumber of Douglas Fir-Larch, Hem-Fir, Southern Pine and Spruce-Pine Fir.
c. Use for cases in which the roof live load is equal to or less than 20 psf.
d. Values are for 30 psf ground snow load.
e. Building width is measured perpendicular to the ridge. For widths between those shown, spans are permitted to be interpolated.
f. NJ = Number of jack studs required to support each end. Where the number of required jack studs equals one, the header is permitted to be supported by an approved framing anchor attached to the full-height wall stud and to the header.
g. Spans are calculated assuming the top of the header or girder is laterally braced by perpendicular framing. Where the top of the header or girder is not laterally braced (for example, cripple studs bearing on the header), tabulated spans for headers consisting of 2 × 8, 2 × 10, or 2 × 12 sizes shall be multiplied by 0.70 or the header or girder shall be designed.
Table 2308.4.1.1(2) Header and Girder Spans
a, b
for Interior Bearing Walls (Maximum spans for Douglas Fir-Larch, Hem-Fir, Southern Pine and Spruce-Pine-Fir and required number of jack studs)
Headers and Girders Supporting
Size
Building width
c
(feet)
12
24
36
Span
e
NJ
d
Span
e
NJ
d
Span
e
NJ
d
One floor only
2-2 x 4
4-1
1
2-10
1
2-4
1
2-2 x 6
6-1
1
4-4
1
3-6
1
2-2 x 8
7-9
1
5-5
1
4-5
2
2-2 x 10
9-2
1
6-6
2
5-3
2
2-2 x 12
10-9
1
7-7
2
6-3
2
3-2 x 8
9-8
1
6-10
1
5-7
1
3-2 x 10
11-5
1
8-1
1
6-7
2
3-2 x 12
13-6
1
9-6
2
7-9
2
4-2 x 8
11-2
1
7-11
1
6-5
1
4-2 x 10
13-3
1
9-4
1
7-8
1
4-2 x 12
15-7
1
11-0
1
9-0
2
Two floors
2-2 x 4
2-7
1
1-11
1
1-7
1
2-2 x 6
3-11
1
2-11
2
2-5
2
2-2 x 8
5-0
1
3-8
2
3-1
2
2-2 x 10
5-11
2
4-4
2
3-7
2
2-2 x 12
6-11
2
5-2
2
4-3
3
3-2 x 8
6-3
1
4-7
2
3-10
2
3-2 x 10
7-5
1
5-6
2
4-6
2
3-2 x 12
8-8
2
6-5
2
5-4
2
4-2 x 8
7-2
1
5-4
1
4-5
2
4-2 x 10
8-6
1
6-4
2
5-3
2
4-2 x 12
10-1
1
7-5
2
6-2
2
For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa.
a. Spans are given in feet and inches.
b. Spans are based on minimum design properties for No. 2 grade lumber of Douglas Fir-Larch, Hem-Fir, Southern Pine and Spruce-Pine Fir.
c. Building width is measured perpendicular to the ridge. For widths between those shown, spans are permitted to be interpolated.
d. NJ = Number of jack studs required to support each end. Where the number of required jack studs equals one, the header is permitted to be supported by an approved framing anchor attached to the full-height wall stud and to the header.
e. Spans are calculated assuming the top of the header or girder is laterally braced by perpendicular framing. Where the top of the header or girder is not laterally braced (for example, cripple studs bearing on the header), tabulated spans for headers consisting of 2 × 8, 2 × 10, or 2 × 12 sizes shall be multiplied by 0.70 or the header or girder shall be designed.
2308.4.2 Floor joists.
Floor joists shall comply with this section.
2308.4.2.1 Span.
Spans for floor joists shall be in accordance with Table 2308.4.2.1(1) or 2308.4.2.1(2) or the AWC STJR.
Table 2308.4.2.1(1) Floor Joist Spans for Common Lumber Species (Residential sleeping areas, live load = 30 psf, L/
D
= 360)
Joist Spacing (inches)
Species and Grade
Dead Load = 10 psf
Dead Load = 20 psf
2 × 6
2 × 8
2 × 10
2 × 12
2 × 6
2 × 8
2 × 10
2 × 12
Maximum floor joist spans
(ft.-in.)
(ft.-in.)
(ft.-in.)
(ft.-in.)
(ft.-in.)
(ft.-in.)
(ft.-in.)
(ft.-in.)
12
Douglas Fir-Larch
SS
12-6
16-6
21-0
25-7
12-6
16-6
21-0
25-7
Douglas Fir-Larch
#1
12-0
15-10
20-3
24-8
12-0
15-7
19-0
22-0
Douglas Fir-Larch
#2
11-10
15-7
19-10
23-0
11-6
14-7
17-9
20-7
Douglas Fir-Larch
#3
9-8
12-4
15-0
17-5
8-8
11-0
13-5
15-7
Hem-Fir
SS
11-10
15-7
19-10
24-2
11-10
15-7
19-10
24-2
Hem-Fir
#1
11-7
15-3
19-5
23-7
11-7
15-2
18-6
21-6
Hem-Fir
#2
11-0
14-6
18-6
22-6
11-0
14-4
17-6
20-4
Hem-Fir
#3
9-8
12-4
15-0
17-5
8-8
11-0
13-5
15-7
Southern Pine
SS
12-3
16-2
20-8
25-1
12-3
16-2
20-8
25-1
Southern Pine
#1
11-10
15-7
19-10
24-2
11-10
15-7
18-7
22-0
Southern Pine
#2
11-3
14-11
18-1
21-4
10-9
13-8
16-2
19-1
Southern Pine
#3
9-2
11-6
14-0
16-6
8-2
10-3
12-6
14-9
Spruce-Pine-Fir
SS
11-7
15-3
19-5
23-7
11-7
15-3
19-5
23-7
Spruce-Pine-Fir
#1
11-3
14-11
19-0
23-0
11-3
14-7
17-9
20-7
Spruce-Pine-Fir
#2
11-3
14-11
19-0
23-0
11-3
14-7
17-9
20-7
Spruce-Pine-Fir
#3
9-8
12-4
15-0
17-5
8-8
11-0
13-5
15-7
16
Douglas Fir-Larch
SS
11-4
15-0
19-1
23-3
11-4
15-0
19-1
23-0
Douglas Fir-Larch
#1
10-11
14-5
18-5
21-4
10-8
13-6
16-5
19-1
Douglas Fir-Larch
#2
10-9
14-1
17-2
19-11
9-11
12-7
15-5
17-10
Douglas Fir-Larch
#3
8-5
10-8
13-0
15-1
7-6
9-6
11-8
13-6
Hem-Fir
SS
10-9
14-2
18-0
21-11
10-9
14-2
18-0
21-11
Hem-Fir
#1
10-6
13-10
17-8
20-9
10-4
13-1
16-0
18-7
Hem-Fir
#2
10-0
13-2
16-10
19-8
9-10
12-5
15-2
17-7
Hem-Fir
#3
8-5
10-8
13-0
15-1
7-6
9-6
11-8
13-6
Southern Pine
SS
11-2
14-8
18-9
22-10
11-2
14-8
18-9
22-10
Southern Pine
#1
10-9
14-2
18-0
21-4
10-9
13-9
16-1
19-1
Southern Pine
#2
10-3
13-3
15-8
18-6
9-4
11-10
14-0
16-6
Southern Pine
#3
7-11
10-10
12-1
14-4
7-1
8-11
10-10
12-10
Spruce-Pine-Fir
SS
10-6
13-10
17-8
21-6
10-6
13-10
17-8
21-4
Spruce-Pine-Fir
#1
10-3
13-6
17-2
19-11
9-11
12-7
15-5
17-10
Spruce-Pine-Fir
#2
10-3
13-6
17-2
19-11
9-11
12-7
15-5
17-10
Spruce-Pine-Fir
#3
8-5
10-8
13-0
15-1
7-6
9-6
11-8
13-6
19.2
Douglas Fir-Larch
SS
10-8
14-1
18-0
21-10
10-8
14-1
18-0
21-0
Douglas Fir-Larch
#1
10-4
13-7
16-9
19-6
9-8
12-4
15-0
17-5
Douglas Fir-Larch
#2
10-1
12-10
15-8
18-3
9-1
11-6
14-1
16-3
Douglas Fir-Larch
#3
7-8
9-9
11-10
13-9
6-10
8-8
10-7
12-4
Hem-Fir
SS
10-1
13-4
17-0
20-8
10-1
13-4
17-0
20-7
Hem-Fir
#1
9-10
13-0
16-4
19-0
9-6
12-0
14-8
17-0
Hem-Fir
#2
9-5
12-5
15-6
17-1
8-11
11-4
13-10
16-1
Hem-Fir
#3
7-8
9-9
11-10
13-9
6-10
8-8
10-7
12-4
Southern Pine
SS
10-6
13-10
17-8
21-6
10-6
13-10
17-8
21-6
Southern Pine
#1
10-1
13-4
16-5
19-6
9-11
12-7
14-8
17-5
Southern Pine
#2
9-6
12-1
14-4
16-10
8-6
10-10
12-10
15-1
Southern Pine
#3
7-3
9-1
11-0
13-1
6-5
8-2
9-10
11-8
Spruce-Pine-Fir
SS
9-10
13-0
16-7
20-2
9-10
13-0
16-7
19-6
Spruce-Pine-Fir
#1
9-8
12-9
15-8
18-3
9-1
11-6
14-1
16-3
Spruce-Pine-Fir
#2
9-8
12-9
15-8
18-3
9-1
11-6
14-1
16-3
Spruce-Pine-Fir
#3
7-8
9-9
11-10
13-9
6-10
8-8
10-7
12-4
24
Douglas Fir-Larch
SS
9-11
13-1
16-8
20-3
9-11
13-1
16-2
18-9
Douglas Fir-Larch
#1
9-7
12-4
15-0
17-5
8-8
11-0
13-5
15-7
Douglas Fir-Larch
#2
9-1
11-6
14-1
16-3
8-1
10-3
12-7
14-7
Douglas Fir-Larch
#3
6-10
8-8
10-7
12-4
6-2
7-9
9-6
11-0
Hem-Fir
SS
9-4
12-4
15-9
19-2
9-4
12-4
15-9
18-5
Hem-Fir
#1
9-2
12-0
14-8
17-0
8-6
10-9
13-1
15-2
Hem-Fir
#2
8-9
11-4
13-10
16-1
8-0
10-2
12-5
14-4
Hem-Fir
#3
6-10
8-8
10-7
12-4
6-2
7-9
9-6
11-0
Southern Pine
SS
9-9
12-10
16-5
19-11
9-9
12-10
16-5
19-8
Southern Pine
#1
9-4
12-4
14-8
17-5
8-10
11-3
13-1
15-7
Southern Pine
#2
8-6
10-10
12-10
15-1
7-7
9-8
11-5
13-6
Southern Pine
#3
6-5
8-2
9-10
11-8
5-9
7-3
8-10
10-5
Spruce-Pine-Fir
SS
9-2
12-1
15-5
18-9
9-2
12-1
15-0
17-5
Spruce-Pine-Fir
#1
8-11
11-6
14-1
16-3
8-1
10-3
12-7
14-7
Spruce-Pine-Fir
#2
8-11
11-6
14-1
16-3
8-1
10-3
12-7
14-7
Spruce-Pine-Fir
#3
6-10
8-8
10-7
12-4
6-2
7-9
9-6
11-0
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
Note: Check sources for availability of lumber in lengths greater than 20 feet.
Table 2308.4.2.1(2) Floor Joist Spans for Common Lumber Species (Residential living areas, live load = 40 psf, L/
D
= 360)
Joist Spacing (inches)
Species and Grade
Dead Load = 10 psf
Dead Load = 20 psf
2 × 6
2 × 8
2 × 10
2 × 12
2 × 6
2 × 8
2 × 10
2 × 12
Maximum floor joist spans
(ft.-in.)
(ft.-in.)
(ft.-in.)
(ft.-in.)
(ft.-in.)
(ft.-in.)
(ft.-in.)
(ft.-in.)
12
Douglas Fir-Larch
SS
11-4
15-0
19-1
23-3
11-4
15-0
19-1
23-3
Douglas Fir-Larch
#1
10-11
14-5
18-5
22-0
10-11
14-2
17-4
20-1
Douglas Fir-Larch
#2
10-9
14-2
17-9
20-7
10-6
13-3
16-3
18-10
Douglas Fir-Larch
#3
8-8
11-0
13-5
15-7
7-11
10-0
12-3
14-3
Hem-Fir
SS
10-9
14-2
18-0
21-11
10-9
14-2
18-0
21-11
Hem-Fir
#1
10-6
13-10
17-8
21-6
10-6
13-10
16-11
19-7
Hem-Fir
#2
10-0
13-2
16-10
20-4
10-0
13-1
16-0
18-6
Hem-Fir
#3
8-8
11-0
13-5
15-7
7-11
10-0
12-3
14-3
Southern Pine
SS
11-2
14-8
18-9
22-10
11-2
14-8
18-9
22-10
Southern Pine
#1
10-9
14-2
18-0
21-11
10-9
14-2
16-11
20-1
Southern Pine
#2
10-3
13-6
16-2
19-1
9-10
12-6
14-9
17-5
Southern Pine
#3
8-2
10-3
12-6
14-9
7-5
9-5
11-5
13-6
Spruce-Pine-Fir
SS
10-6
13-10
17-8
21-6
10-6
13-10
17-8
21-6
Spruce-Pine-Fir
#1
10-3
13-6
17-3
20-7
10-3
13-3
16-3
18-10
Spruce-Pine-Fir
#2
10-3
13-6
17-3
20-7
10-3
13-3
16-3
18-10
Spruce-Pine-Fir
#3
8-8
11-0
13-5
15-7
7-11
10-0
12-3
14-3
16
Douglas Fir-Larch
SS
10-4
13-7
17-4
21-1
10-4
13-7
17-4
21-0
Douglas Fir-Larch
#1
9-11
13-1
16-5
19-1
9-8
12-4
15-0
17-5
Douglas Fir-Larch
#2
9-9
12-7
15-5
17-10
9-1
11-6
14-1
16-3
Douglas Fir-Larch
#3
7-6
9-6
11-8
13-6
6-10
8-8
10-7
12-4
Hem-Fir
SS
9-9
12-10
16-5
19-11
9-9
12-10
16-5
19-11
Hem-Fir
#1
9-6
12-7
16-0
18-7
9-6
12-0
14-8
17-0
Hem-Fir
#2
9-1
12-0
15-2
17-7
8-11
11-4
13-10
16-1
Hem-Fir
#3
7-6
9-6
11-8
13-6
6-10
8-8
10-7
12-4
Southern Pine
SS
10-2
13-4
17-0
20-9
10-2
13-4
17-0
20-9
Southern Pine
#1
9-9
12-10
16-1
19-1
9-9
12-7
14-8
17-5
Southern Pine
#2
9-4
11-10
14-0
16-6
8-6
10-10
12-10
15-1
Southern Pine
#3
7-1
8-11
10-10
12-10
6-5
8-2
9-10
11-8
Spruce-Pine-Fir
SS
9-6
12-7
16-0
19-6
9-6
12-7
16-0
19-6
Spruce-Pine-Fir
#1
9-4
12-3
15-5
17-10
9-1
11-6
14-1
16-3
Spruce-Pine-Fir
#2
9-4
12-3
15-5
17-10
9-1
11-6
14-1
16-3
Spruce-Pine-Fir
#3
7-6
9-6
11-8
13-6
6-10
8-8
10-7
12-4
19.2
Douglas Fir-Larch
SS
9-8
12-10
16-4
19-10
9-8
12-10
16-4
19-2
Douglas Fir-Larch
#1
9-4
12-4
15-0
17-5
8-10
11-3
13-8
15-11
Douglas Fir-Larch
#2
9-1
11-6
14-1
16-3
8-3
10-6
12-10
14-10
Douglas Fir-Larch
#3
6-10
8-8
10-7
12-4
6-3
7-11
9-8
11-3
Hem-Fir
SS
9-2
12-1
15-5
18-9
9-2
12-1
15-5
18-9
Hem-Fir
#1
9-0
11-10
14-8
17-0
8-8
10-11
13-4
15-6
Hem-Fir
#2
8-7
11-3
13-10
16-1
8-2
10-4
12-8
14-8
Hem-Fir
#3
6-10
8-8
10-7
12-4
6-3
7-11
9-8
11-3
Southern Pine
SS
9-6
12-7
16-0
19-6
9-6
12-7
16-0
19-6
Southern Pine
#1
9-2
12-1
14-8
17-5
9-0
11-5
13-5
15-11
Southern Pine
#2
8-6
10-10
12-10
15-1
7-9
9-10
11-8
13-9
Southern Pine
#3
6-5
8-2
9-10
11-8
5-11
7-5
9-0
10-8
Spruce-Pine-Fir
SS
9-0
11-10
15-1
18-4
9-0
11-10
15-1
17-9
Spruce-Pine-Fir
#1
8-9
11-6
14-1
16-3
8-3
10-6
12-10
14-10
Spruce-Pine-Fir
#2
8-9
11-6
14-1
16-3
8-3
10-6
12-10
14-10
Spruce-Pine-Fir
#3
6-10
8-8
10-7
12-4
6-3
7-11
9-8
11-3
24
Douglas Fir-Larch
SS
9-0
11-11
15-2
18-5
9-0
11-11
14-9
17-1
Douglas Fir-Larch
#1
8-8
11-0
13-5
15-7
7-11
10-0
12-3
14-3
Douglas Fir-Larch
#2
8-1
10-3
12-7
14-7
7-5
9-5
11-6
13-4
Douglas Fir-Larch
#3
6-2
7-9
9-6
11-0
5-7
7-1
8-8
10-1
Hem-Fir
SS
8-6
11-3
14-4
17-5
8-6
11-3
14-4
16-10a
Hem-Fir
#1
8-4
10-9
13-1
15-2
7-9
9-9
11-11
13-10
Hem-Fir
#2
7-11
10-2
12-5
14-4
7-4
9-3
11-4
13-1
Hem-Fir
#3
6-2
7-9
9-6
11-0
5-7
7-1
8-8
10-1
Southern Pine
SS
8-10
11-8
14-11
18-1
8-10
11-8
14-11
18-0
Southern Pine
#1
8-6
11-3
13-1
15-7
8-1
10-3
12-0
14-3
Southern Pine
#2
7-7
9-8
11-5
13-6
7-0
8-10
10-5
12-4
Southern Pine
#3
5-9
7-3
8-10
10-5
5-3
6-8
8-1
9-6
Spruce-Pine-Fir
SS
8-4
11-0
14-0
17-0
8-4
11-0
13-8
15-11
Spruce-Pine-Fir
#1
8-1
10-3
12-7
14-7
7-5
9-5
11-6
13-4
Spruce-Pine-Fir
#2
8-1
10-3
12-7
14-7
7-5
9-5
11-6
13-4
Spruce-Pine-Fir
#3
6-2
7-9
9-6
11-0
5-7
7-1
8-8
10-1
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
Note: Check sources for availability of lumber in lengths greater than 20 feet.
a. End bearing length shall be increased to 2 inches.
2308.4.2.2 Bearing.
The ends of each joist shall have not less than 1 1/2 inches (38 mm) of bearing on wood or metal, or not less than 3 inches (76 mm) on masonry, except where supported on a 1-inch by 4-inch (25 mm by 102 mm) ribbon strip and nailed to the adjoining stud.
2308.4.2.3 Framing details.
Joists shall be supported laterally at the ends and at each support by solid blocking except where the ends of the joists are nailed to a header, band or rim joist or to an adjoining stud or by other means. Solid blocking shall be not less than 2 inches (51 mm) in thickness and the full depth of the joist. Joist framing from opposite sides of a beam, girder or partition shall be lapped at least 3 inches (76 mm) or the opposing joists shall be tied together in an approved manner. Joists framing into the side of a wood girder shall be supported by framing anchors or on ledger strips not less than 2 inches by 2 inches (51 mm by 51 mm).
2308.4.2.4 Notches and holes.
Notches on the ends of joists shall not exceed one-fourth the joist depth. Notches in the top or bottom of joists shall not exceed one-sixth the depth, shall not be longer than one-third the depth and shall not be located in the middle third of the span. Holes bored in joists shall not be within 2 inches (51 mm) of the top or bottom of the joist and the diameter of any such hole shall not exceed one-third the depth of the joist. Holes bored in the middle third of the span shall be located at the center of the joist depth. Clear distance between holes & notches shall be a minimum of 2 inches (51 mm). See Figure 2308.4.2.4.
Figure 2308.4.2.4 Joist Boring and Notching Limits Not to Scale
2308.4.3 Engineered wood products.
Engineered wood products shall be installed in accordance with manufacturer's recommendations. Cuts, notches and holes bored in trusses, structural composite lumber, structural glued-laminated members or I-joists are prohibited except where permitted by the manufacturer's recommendations or where the effects of such alterations are specifically considered in the design of the member by a registered design professional.
2308.4.4 Framing around openings.
Trimmer and header joists 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 joists more than 6 feet (1829 mm) in length shall be supported by framing anchors or joist hangers unless bearing on a beam, partition or wall. Tail joists over 12 feet (3658 mm) in length shall be supported at the header by framing anchors or on ledger strips not less than 2 inches by 2 inches (51 mm by 51 mm).
2308.4.4.1 Openings in floor diaphragms in Seismic Design Categories B, C, and D.
Openings in horizontal diaphragms in Seismic Design Categories B, C, and D with a dimension that is greater than 4 feet (1219 mm) shall be constructed with metal ties and blocking in accordance with this section and Figure 2308.4.4.1(1). Metal ties shall be not less than 0.058 inch (1.47 mm) (16 galvanized gage) in thickness by 1 1/2 inches (38 mm) in width and shall have a yield stress not less than 33,000 psi (227 Mpa). Blocking shall extend not less than the dimension of the opening in the direction of the tie and blocking. Ties shall be attached to blocking in accordance with the manufacturer's instructions but with not less than eight 16d common nails on each side of the header-joist intersection.
Openings in floor diaphragms in Seismic Design Category D shall not have any dimension exceeding 50 percent of the distance between braced wall lines or an area greater than 25 percent of the area between orthogonal pairs of braced wall lines (see Figure 2308.4.4.1(2)); or the portion of the structure containing the opening shall be designed in accordance with accepted engineering practice to resist the forces specified in Chapter 16, to the extent such irregular opening affects the performance of the conventional framing system.
Figure 2308.4.4.1(1) Openings in Floor and Roof Diaphragms
Figure 2308.4.4.1(2) Opening Limitations for Floor and Roof Diaphragms
2308.4.4.2 Vertical offsets in floor diaphragms in Seismic Design Category D.
In Seismic Design Category D, portions of a floor level shall not be vertically offset such that the framing members on either side of the offset cannot be lapped or tied together in an approved manner in accordance with Figure 2308.4.4.2 unless the portion of the structure containing the irregular offset is designed in accordance with accepted engineering practice.
Exception: Framing supported directly by foundations need not be lapped or tied directly together.
Figure 2308.4.4.2 Portions of Floor Level Offset Vertically
2308.4.5 Joists supporting bearing partitions.
Bearing partitions parallel to joists shall be supported on beams, girders, doubled joists, walls or other bearing partitions. Bearing partitions perpendicular to joists shall not be offset from supporting girders, walls or partitions more than the joist depth unless such joists are of sufficient size to carry the additional load.
2308.4.6 Lateral support.
Floor and ceiling framing with a nominal depth-to-thickness ratio not less than 5 to 1 shall have one edge held in line for the entire span. Where the nominal depth-to-thickness ratio of the framing member exceeds 6 to 1, there shall be one line of bridging for each 8 feet (2438 mm) of span, unless both edges of the member are held in line. The bridging shall consist of not less than 1-inch by 3-inch (25 mm by 76 mm) lumber, double nailed at each end, or equivalent metal bracing of equal rigidity, full-depth solid blocking or other approved means. A line of bridging shall also be required at supports where equivalent lateral support is not otherwise provided.
2308.4.7 Structural floor sheathing.
Structural floor sheathing shall comply with the provisions of Section 2304.8.1.
2308.4.8 Under-floor ventilation.
For under-floor ventilation, see Section 1203.4.
2308.4.9 Floor framing supporting braced wall panels.
Where braced wall panels are supported by cantilevered floors or are set back from the floor joist support, the floor framing shall comply with Section 2308.6.7.
2308.4.10 Anchorage of exterior means of egress components in Seismic Design Category D.
Exterior egress balconies, exterior stairways and ramps and similar means of egress components in structures assigned to Seismic Design Category D shall be positively anchored to the primary structure at not more than 8 feet (2438 mm) on center or shall be designed for lateral forces. Such attachment shall not be accomplished by use of toenails or nails subject to withdrawal.
2308.5 Wall construction.
Walls of conventional light-frame construction shall be in accordance with this section.
2308.5.1 Stud size, height and spacing.
The size, height and spacing of studs shall be in accordance with Table 2308.5.1.
Studs shall be continuous from a support at the sole plate to a support at the top plate to resist loads perpendicular to the wall. The support shall be a foundation or floor, ceiling or roof diaphragm or shall be designed in accordance with accepted engineering practice.
Exception: Jack studs, trimmer studs and cripple studs at openings in walls that comply with Table 2308.4.1.1(1) or 2308.4.1.1(2).
Table 2308.5.1 Size, Height and Spacing of Wood Studs
c
Stud Size (inches)
Bearing Walls
Nonbearing Walls
Laterally unsupported stud height
a
(feet)
Supporting roof and ceiling only
Supporting one floor, roof and ceiling
Supporting two floors, roof and ceiling
Laterally unsupported stud height
a
(feet)
Spacing (inches)
Spacing (inches)
2 × 3
b
—
—
—
—
10
16
2 × 4 10
10
24
16
—
14
24
3 × 4 10
10
24
24
16
14
24
2 × 5 10
10
24
24
—
16
24
2 × 6 10
19
24
24
16
20
24
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
a. Listed heights are distances between points of lateral support placed perpendicular to the plane of the wall. Increases in unsupported height are permitted where justified by an analysis.
b. Shall not be used in exterior walls.
c. Utility-grade studs shall not be spaced more than 16 inches on center or support more than a roof and ceiling, or exceed 8 feet in height for exterior walls and load-bearing walls or 10 feet for interior nonload-bearing walls.
2308.5.2 Framing details.
Studs shall be placed with their wide dimension perpendicular to the wall. Not less than three studs shall be installed at each corner of an exterior wall.
Exceptions:
1. In interior nonload-bearing walls and partitions that are not braced wall panels, studs are permitted to be set with the long dimension parallel to the wall.
2. At corners, two studs are permitted, provided that wood spacers or backup cleats of 3/8-inch-thick (9.5 mm) wood structural panel, 3/8-inch (9.5 mm) Type M "Exterior Glue" particleboard, 1-inch-thick (25 mm) lumber or other approved devices that will serve as an adequate backing for the attachment of facing materials are used. Where fire-resistance ratings or shear values are involved, wood spacers, backup cleats or other devices shall not be used unless specifically approved for such use.
2308.5.3 Plates and sills.
Studs shall have plates and sills in accordance with this section.
2308.5.3.1 Bottom plate or sill.
Studs shall have full bearing on a plate or sill. Plates or sills shall be not less than 2 inches (51 mm) nominal in thickness and have a width not less than the width of the wall studs.
2308.5.3.2 Top plates.
Bearing and exterior wall studs shall be capped with double top plates installed to provide overlapping at corners and at intersections with other partitions. End joints in double top plates shall be offset not less than 48 inches (1219 mm), and shall be nailed in accordance with Table 2304.10.1. Plates shall be a nominal 2 inches (51 mm) in depth and have a width not less than the width of the studs.
Exception: A single top plate is permitted, provided that the plate is adequately tied at corners and intersecting walls by not less than the equivalent of a 3-inch by 6-inch (76 mm by 152 mm) by 0.036-inch-thick (0.914 mm) galvanized steel plate that is nailed to each wall or segment of wall by six 8d (2 1/2" × 0.113" (64 mm by 2.87 mm)) box nails or equivalent on each side of the joint. For the butt-jointed splice between adjacent single top plates, not less than the equivalent of a 3-inch by 12-inch (76 mm by 304 mm) by 0.036-inch-thick (0.914 mm) galvanized steel plate that is nailed to each wall or segment of wall by twelve 8d (2 1/2-inch × 0.113-inch (64 mm by 2.87 mm)) box nails on each side of the joint shall be required, provided that the rafters, joists or trusses are centered over the studs with a tolerance of not more than 1 inch (25 mm). The top plate shall not be required over headers that are in the same plane and in line with the upper surface of the adjacent top plates and are tied to adjacent wall sections as required for the butt joint splice between adjacent single top plates.
Where bearing studs are spaced at 24-inch (610 mm) intervals, top plates are less than two 2-inch by 6-inch (51 mm by 152 mm) or two 3-inch by 4-inch (76 mm by 102 mm) members and the floor joists, floor trusses or roof trusses that they support are spaced at more than 16-inch (406 mm) intervals, such joists or trusses shall bear within 5 inches (127 mm) of the studs beneath or a third plate shall be installed.
2308.5.4 Nonload-bearing walls and partitions.
In nonload-bearing walls and partitions that are not part of a braced wall panel, studs shall be spaced not more than 24 inches (610 mm) on center. In interior nonload-bearing walls and partitions, studs are permitted to be set with the long dimension parallel to the wall. Where studs are set with the long dimensions parallel to the wall, use of utility grade lumber or studs exceeding 10 feet (3048 mm) is not permitted. Interior nonload-bearing partitions shall be capped with not less than a single top plate installed to provide overlapping at corners and at intersections with other walls and partitions. The plate shall be continuously tied at joints by solid blocking not less than 16 inches (406 mm) in length and equal in size to the plate or by 1/2-inch by 1 1/2-inch (12.7 mm by 38 mm) metal ties with spliced sections fastened with two 16d nails on each side of the joint.
2308.5.5 Openings in walls and partitions.
Openings in exterior and interior walls and partitions shall comply with Sections 2308.5.5.1 through 2308.5.5.3.
2308.5.5.1 Openings in exterior bearing walls.
Headers shall be provided over each opening in exterior bearing walls. The size and spans in Table 2308.4.1.1(1) are permitted to be used for one- and two-family dwellings. Headers for other buildings shall be designed in accordance with Section 2301.2, Item 1 or 2. Headers shall be of two pieces of nominal 2-inch (51 mm) framing lumber set on edge as permitted by Table 2308.4.1.1(1) and nailed together in accordance with Table 2304.10.1 or of solid lumber of equivalent size.
Wall studs shall support the ends of the header in accordance with Table 2308.4.1.1(1). Each end of a lintel or header shall have a bearing length of not less than 1 1/2 inches (38 mm) for the full width of the lintel.
2308.5.5.2 Openings in interior bearing partitions.
Headers shall be provided over each opening in interior bearing partitions as required in Section 2308.5.5.1. The spans in Table 2308.4.1.1(2) are permitted to be used. Wall studs shall support the ends of the header in accordance with Table 2308.4.1.1(1) or 2308.4.1.1(2), as applicable.
2308.5.5.3 Openings in interior nonload-bearing partitions.
Openings in nonload-bearing partitions are permitted to be framed with single studs and headers. Each end of a lintel or header shall have a bearing length of not less than 1 1/2 inches (38 mm) for the full width of the lintel.
2308.5.6 Cripple walls.
Foundation cripple walls shall be framed of studs that are not less than the size of the studding above and not less than 14 inches (356 mm) in length, or shall be framed of solid blocking. Where exceeding 4 feet (1219 mm) in height, such walls shall be framed of studs having the size required for an additional story. See Section 2308.6.6 for cripple wall bracing.
2308.5.7 Bridging.
Unless covered by interior or exterior wall coverings or sheathing meeting the minimum requirements of this code, stud partitions or walls with studs having a height-to-least-thickness ratio exceeding 50 shall have bridging that is not less than 2 inches (51 mm) in thickness and of the same width as the studs fitted snugly and nailed thereto to provide adequate lateral support. Bridging shall be placed in every stud cavity and at a frequency such that no stud so braced shall have a height-to-least-thickness ratio exceeding 50 with the height of the stud measured between horizontal framing and bridging or between bridging, whichever is greater.
2308.5.8 Pipes in walls.
Stud partitions containing plumbing, heating or other pipes shall be framed and the joists underneath spaced to provide proper clearance for the piping. Where a partition containing piping runs parallel to the floor joists, the joists underneath such partitions shall be doubled and spaced to permit the passage of pipes and shall be bridged. Where plumbing, heating or other pipes are placed in, or partly in, a partition, necessitating the cutting of the soles or plates, a metal tie not less than 0.058 inch (1.47 mm) (16 galvanized gage) and 1 1/2 inches (38 mm) in width shall be fastened to each plate across and to each side of the opening a minimum of 6 inches (152 mm) with not less than six 16d nails. See Figure 2308.5.8.
Figure 2308.5.8 Wall Boring and Notching Limits Not to Scale
2308.5.9 Cutting and notching.
In exterior walls and bearing partitions, wood studs are permitted to be cut or notched to a depth not exceeding 25 percent of the width of the stud. Cutting or notching of studs to a depth not greater than 40 percent of the width of the stud is permitted in nonload-bearing partitions supporting no loads other than the weight of the partition. See Figure 2308.5.8.
2308.5.10 Bored holes.
Bored holes not greater than 40 percent of the stud width are permitted to be bored in any wood stud. Bored holes not greater than 60 percent of the stud width are permitted in nonload-bearing partitions or in any wall where each bored stud is doubled, provided not more than two such successive doubled studs are so bored. In no case shall the edge of a bored hole be nearer than 5/8 inch (15.9 mm) to the edge of the stud. Bored holes shall not be located at the same section of stud as a cut or notch. See Figure 2308.5.8.
2308.5.11 Exterior wall sheathing.
Except where stucco construction that complies with Section 2510 is installed, the outside of exterior walls of enclosed buildings, including gables, shall be sheathed with one of the materials of the minimum thickness specified in Table 2308.5.11. Fasteners shall be used that are designed in accordance with the requirements of Section 2304.10 or accepted engineering practice. Alternatively, sheathing materials and fasteners complying with Section 2304.6 shall be permitted.
Table 2308.5.11 Minimum Thickness of Wall Sheathing
Sheathing Type
Minimum Thickness
Maximum Wall Stud Spacing
Diagonal wood boards
5/8 inch
24 inches on center
Structural fiberboard
1/2 inch
16 inches on center
Wood structural panel
In accordance with
Tables 2308.6.3(2) and 2308.6.3(3)
—
M-S "Exterior Glue" and M-2 "Exterior Glue" particleboard
In accordance with Section 2306.3 and Table 2308.6.3(4)
—
Gypsum sheathing
1/2 inch
16 inches on center
Reinforced cement mortar
1 inch
24 inches on center
Hardboard panel siding
In accordance with
Table 2308.6.3(5)
—
For SI: 1 inch = 25.4 mm.
2308.6 Wall bracing.
Buildings shall be provided with exterior and interior braced wall lines as described in Sections 2308.6.1 through 2308.6.10.2.
2308.6.1 Braced wall lines.
For the purpose of determining the amount and location of bracing required along each story level of a building, braced wall lines shall be designated as straight lines through the building plan in both the longitudinal and transverse direction and placed in accordance with Table 2308.6.1 and Figure 2308.6.1. Braced wall line spacing shall not exceed the distance specified in Table 2308.6.1. In structures assigned to Seismic Design Category D, braced wall lines shall intersect perpendicularly to each other.
For SI: 1 foot = 304.8 mm.
Figure 2308.6.1 Basic Components of the Lateral Bracing System
Table 2308.6.1
a
Wall Bracing Requirements
Seismic Design Category
Story Condition (See Section 2308.2)
Maximum Spacing of Braced Wall Lines
Braced Panel Location, Spacing (o.c.) and Minimum Percentage (X)
Maximum Distance of Braced Wall Panels from Each End of Braced Wall Line
Bracing method
b
LIB
DWB, WSP
SFB, PBS, PCP, HPS, GB
c, d
A and B
35' - 0"
Each end and
£ 25' - 0" o.c.
Each end and
£ 25' - 0" o.c.
Each end and
£ 25' - 0" o.c.
12' - 6"
35' - 0"
Each end and
£ 25' - 0" o.c.
Each end and
£ 25' - 0" o.c.
Each end and
£ 25' - 0" o.c.
12' - 6"
35' - 0"
NP
Each end and
£ 25' - 0" o.c.
Each end and
£ 25' - 0" o.c.
12' - 6"
C
35' - 0"
NP
Each end and
£ 25' - 0" o.c.
Each end and
£ 25' - 0" o.c.
12' - 6"
35' - 0"
NP
Each end and
£ 25' - 0" o.c. (minimum 25% of wall length)
e
Each end and
£ 25' - 0" o.c. (minimum 25% of wall length)
e
12' - 6"
D
25' - 0"
NP
S
DS
< 0.50: Each end and
£ 25' - 0" o.c (minimum 21% of wall length)
e
S
DS
< 0.50: Each end and
£ 25' - 0" o.c (minimum 43% of wall length)
e
8' - 0"
0.5 £
S
DS
< 0.75: Each end and
£ 25' - 0" o.c. (minimum 32% of wall length)
e
0.5 £
S
DS
< 0.75: Each end and
£ 25' - 0" o.c. (minimum 59% of wall length)
e
0.75 £
S
DS
£ 1.00: Each end and
£ 25' - 0" o.c. (minimum 37% of wall length)
e
0.75 £
S
DS
£ 1.00: Each end and
£ 25' - 0" o.c. (minimum 75% of wall length)
e
S
DS
> 1.00: Each end and
£ 25' - 0" o.c. (minimum 48% of wall length)
e
S
DS
> 1.00: Each end and
£ 25' - 0" o.c. (minimum 100% of wall length)
e
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
NP = Not Permitted.
a. This table specifies minimum requirements for braced wall panels along interior or exterior braced wall lines.
b. See Section 2308.6.3 for full description of bracing methods.
c. For Method GB, gypsum wallboard applied to framing supports that are spaced at 16 inches on center.
d. The required lengths shall be doubled for gypsum board applied to only one face of a braced wall panel.
e. Percentage shown represents the minimum amount of bracing required along the building length (or wall length if the structure has an irregular shape).
2308.6.2 Braced wall panels.
Braced wall panels shall be placed along braced wall lines in accordance with Table 2308.6.1 and Figure 2308.6.1 and as specified in Table 2308.6.3(1). A braced wall panel shall be located at each end of the braced wall line and at the corners of intersecting braced wall lines or shall begin within the maximum distance from the end of the braced wall line in accordance with Table 2308.6.1. Braced wall panels in a braced wall line shall not be offset from each other by more than 4 feet (1219 mm). Braced wall panels shall be clearly indicated on the plans.
2308.6.3 Braced wall panel methods.
Construction of braced wall panels shall be by one or a combination of the methods in Table 2308.6.3(1). Braced wall panel length shall be in accordance with Section 2308.6.4 or 2308.6.5.
Table 2308.6.3(1) Bracing Methods
Methods, Material
Minimum Thickness
Figure
Connection Criteria
a
Fasteners
Spacing
LIB
a
Let-in-bracing
1" × 4" wood or approved metal straps attached at 45° to 60° angles to studs at maximum of 16" o.c.
Table 2304.10.1
Wood: per stud plus top and bottom plates
Metal strap: installed in accordance with manufacturer's recommendations
Metal strap: installed in accordance with manufacturer's recommendations
DWB
Diagonal wood boards
3/4" thick (1" nominal) × 6" minimum width to studs at maximum of 24" o.c.
Table 2304.10.1
Per stud
WSP
Wood structural panel
3/8" in accordance with Table 2308.6.3(2) or 2308.6.3(3)
Table 2304.10.1
6" edges 12" field
SFB
Structural fiberboard sheathing
1/2" in accordance with Table 2304.10.1 to studs at maximum 16" o.c.
Table 2304.10.1
3" edges 6" field
GB
Gypsum board (Double sided)
1/2" or 5/8" by a minimum of 4" wide to studs at maximum of 24" o.c.
Section 2506.2 for exterior and interior sheathing: 5d annual ringed cooler nails (1 5/8" × 0.086") or 1 1/4" screws (Type W or S) for 1/2" gypsum board or 1 5/8" screws (Type W or S) for 5/8" gypsum board
For all braced wall panel locations: 7" o.c. along panel edges (including top and bottom plates) and 7" o.c. in the field
PBS
Particleboard sheathing
3/8" or 1/2" in accordance with Table 2308.6.3(4)
to studs at maximum of 16" o.c.
6d common (2" long × 0.113" dia.) nails for 3/8" thick sheathing or 8d common (2 1/2" long × 0.131" dia.) nails for 1/2" thick sheathing
3" edges 6" field
PCP
Portland cement plaster
Section 2510 to studs at maximum of 16" o.c.
1 1/2" long, 11 gage, 7/16" dia. head nails or 7/8" long, 16 gage staples
6" o.c. on all framing members
HPS
Hardboard panel siding
7/16" in accordance with Table 2308.6.3(5)
Table 2304.10.1
4" edges 8" field
ABW
Alternate braced wall
3/8"
Figure 2308.6.5.1 and Section 2308.6.5.1
Figure 2308.6.5.1
PFH
Portal frame with hold-downs
3/8"
Figure 2308.6.5.2 and Section 2308.6.5.2
Figure 2308.6.5.2
For SI: 1 foot = 304.8 mm, 1 degree = 0.01745 rad.
a. Method LIB shall have gypsum board fastened to at least one side with nails or screws.
Table 2308.6.3(2) Exposed Plywood Panel Siding
Minimum Thickness
a
(inch)
Minimum Number of Plies
Stud Spacing (inches) Plywood siding applied directly to studs or over sheathing
3/8
3
16
b
1/2
4
24
For SI: 1 inch = 25.4 mm.
a. Thickness of grooved panels is measured at bottom of grooves.
b. Spans are permitted to be 24 inches if plywood siding is applied with face grain perpendicular to studs or over one of the following: (1) 1-inch board sheathing, (2) 7/16-inch wood structural panel sheathing or (3) 3/8-inch wood structural panel sheathing with strength axis (which is the long direction of the panel unless otherwise marked) of sheathing perpendicular to studs.
Table 2308.6.3(3) Wood Structural Panel Wall Sheathing
b
(Not Exposed to the Weather, Strength Axis Parallel or Perpendicular to Studs Except as Indicated Below)
Minimum Thickness (inch)
Panel Span Rating
Stud Spacing (inches)
Siding nailed to studs
Nailable sheathing
Sheathing parallel to studs
Sheathing perpendicular to studs
3/8, 15/32, 1/2
16/0, 20/0, 24/0, 32/16 Wall – 24" o.c.
24
16
24
7/16, 15/32, 1/2
24/0, 24/16, 32/16 Wall – 24" o.c.
24
24
a
24
For SI: 1 inch = 25.4 mm.
a. Plywood shall consist of four or more plies.
b. Blocking of horizontal joints shall not be required except as specified in Section 2308.6.4.
Table 2308.6.3(4) Allowable Spans for Particleboard Wall Sheathing (Not Exposed to the Weather, Long Dimension of the Panel Parallel or Perpendicular to Studs)
Grade
Thickness (inch)
Stud Spacing (inches)
Siding nailed to studs
Sheathing under coverings specified in Section 2308.6.3 parallel or perpendicular to studs
M-S "Exterior Glue" nd M-2 "Exterior Glue"
3/8
16
—
1/2
16
16
For SI: 1 inch = 25.4 mm.
Table 2308.6.3(5) Hardboard Siding
Siding
Minimum Nominal Thickness (inch)
2 × 4 Framing Maximum Spacing
Nail Size
a, b, d
Nail Spacing
General
Bracing panels
c
1. Lap siding
Direct to studs
3/8
16" o.c.
8d
16 o.c.
Not applicable
Over sheathing
3/8
16" o.c.
10d
16 o.c.
Not applicable
2. Square edge panel siding
Direct to studs
3/8
24" o.c.
6d
6" o.c. edges; 12" o.c. at intermediate supports
4" o.c. edges; 8" o.c. at intermediate supports
Over sheathing
3/8
24" o.c.
8d
6" o.c. edges; 12" o.c. at intermediate supports
4" o.c. edges; 8" o.c. at intermediate supports
3. Shiplap edge panel siding
Direct to studs
3/8
16" o.c.
6d
6" o.c. edges; 12" o.c. at intermediate supports
4" o.c. edges; 8" o.c. at intermediate supports
Over sheathing
3/8
16" o.c.
8d
6" o.c. edges; 12" o.c. at intermediate supports
4" o.c. edges; 8" o.c. at intermediate supports
For SI: 1 inch = 25.4 mm.
a. Nails shall be corrosion resistant.
b. Minimum acceptable nail dimensions:
Panel Siding (inch)
Lap Siding (inch)
Shank diameter Head diameter
0.092 0.225
0.099 0.240
c. Where used to comply with Section 2308.6.
d. Nail length must accommodate the sheathing and penetrate framing 1 1/2 inches.
2308.6.4 Braced wall panel construction.
For Methods DWB, WSP, SFB, PBS, PCP and HPS, each panel must be not less than 48 inches (1219 mm) in length, covering three stud spaces where studs are spaced 16 inches (406 mm) on center and covering two stud spaces where studs are spaced 24 inches (610 mm) on center. Braced wall panels less than 48 inches (1219 mm) in length shall not contribute toward the amount of required bracing. Braced wall panels that are longer than the required length shall be credited for their actual length. For Method GB, each panel must be not less than 96 inches (2438 mm) in length where applied to one side of the studs or 48 inches (1219 mm) in length where applied to both sides.
Vertical joints of panel sheathing shall occur over studs and adjacent panel joints shall be nailed to common framing members. Horizontal joints shall occur over blocking or other framing equal in size to the studding except where waived by the installation requirements for the specific sheathing materials. Sole plates shall be nailed to the floor framing in accordance with Section 2308.6.7 and top plates shall be connected to the framing above in accordance with Section 2308.6.7.2. Where joists are perpendicular to braced wall lines above, blocking shall be provided under and in line with the braced wall panels.
2308.6.5 Alternative bracing.
An alternate braced wall (ABW) or a portal frame with hold-downs (PFH) described in this section is permitted to substitute for a 48-inch (1219 mm) braced wall panel of Method DWB, WSP, SFB, PBS, PCP or HPS. For Method GB, each 96-inch (2438 mm) section (applied to one face) or 48-inch (1219 mm) section (applied to both faces) or portion thereof required by Table 2308.6.1 is permitted to be replaced by one panel constructed in accordance with Method ABW or PFH.
2308.6.5.1 Alternate braced wall (ABW).
An ABW shall be constructed in accordance with this section and Figure 2308.6.5.1. In one-story buildings, each panel shall have a length of not less than 2 feet 8 inches (813 mm) and a height of not more than 10 feet (3048 mm). Each panel shall be sheathed on one face with 3/8-inch (3.2 mm)* minimum-thickness wood structural panel sheathing nailed with 8d common or galvanized box nails in accordance with Table 2304.10.1 and blocked at wood structural panel edges. Two anchor bolts installed in accordance with Section 2308.3.1 shall be provided in each panel. Anchor bolts shall be placed at each panel outside quarter points. Each panel end stud shall have a hold-down device fastened to the foundation, capable of providing an approved allowable uplift capacity of not less than 1,800 pounds (8006 N). The hold-down device shall be installed in accordance with the manufacturer's recommendations. The ABW shall be supported directly on a foundation or on floor framing supported directly on a foundation that is continuous across the entire length of the braced wall line. This foundation shall be reinforced with not less than one No. 4 bar top and bottom. Where the continuous foundation is required to have a depth greater than 12 inches (305 mm), a minimum 12-inch by 12-inch (305 mm by 305 mm) continuous footing or turned-down slab edge is permitted at door openings in the braced wall line. This continuous footing or turned-down slab edge shall be reinforced with not less than one No. 4 bar top and bottom. This reinforcement shall be lapped 15 inches (381 mm) with the reinforcement required in the continuous foundation located directly under the braced wall line.
Where the ABW is installed at the first story of two-story buildings, the wood structural panel sheathing shall be provided on both faces, three anchor bolts shall be placed at one-quarter points, and tie-down device allowable uplift capacity shall be not less than 3,000 pounds (13 344 N).
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
Figure 2308.6.5.1 Alternate Braced Wall Panel (ABW)
2308.6.5.2 Portal frame with hold-downs (PFH).
A PFH shall be constructed in accordance with this section and Figure 2308.6.5.2. The adjacent door or window opening shall have a full-length header.
In one-story buildings, each panel shall have a length of not less than 16 inches (406 mm) and a height of not more than 10 feet (3048 mm). Each panel shall be sheathed on one face with a single layer of 3/8-inch (9.5 mm) minimum-thickness wood structural panel sheathing nailed with 8d common or galvanized box nails in accordance with Figure 2308.6.5.2. The wood structural panel sheathing shall extend up over the solid sawn or glued-laminated header and shall be nailed in accordance with Figure 2308.6.5.2. A built-up header consisting of at least two 2-inch by 12-inch (51 mm by 305 mm) boards, fastened in accordance with Item 24 of Table 2304.10.1, shall be permitted to be used. A spacer, if used, shall be placed on the side of the built-up beam opposite the wood structural panel sheathing. The header shall extend between the inside faces of the first full-length outer studs of each panel. The clear span of the header between the inner studs of each panel shall be not less than 6 feet (1829 mm) and not more than 18 feet (5486 mm) in length. A strap with an allowable uplift capacity of not less than 1,000 pounds (4400 N) shall fasten the header to the inner studs opposite the sheathing. One anchor bolt not less than 5/8 inch (15.9 mm) diameter and installed in accordance with Section 2308.3.1 shall be provided in the center of each sill plate. The studs at each end of the panel shall have a hold-down device fastened to the foundation with an allowable uplift capacity of not less than 3,500 pounds (15 570 N).
Where a panel is located on one side of the opening, the header shall extend between the inside face of the first full-length stud of the panel and the bearing studs at the other end of the opening. A strap with an allowable uplift capacity of not less than 1,000 pounds (4400 N) shall fasten the header to the bearing studs. The bearing studs shall also have a hold-down device fastened to the foundation with an allowable uplift capacity of not less than 1,000 pounds (4400 N). The hold-down devices shall be an embedded strap type, installed in accordance with the manufacturer's recommendations. The PFH panels shall be supported directly on a foundation that is continuous across the entire length of the braced wall line. This foundation shall be reinforced with not less than one No. 4 bar top and bottom. Where the continuous foundation is required to have a depth greater than 12 inches (305 mm), a minimum 12-inch by 12-inch (305 mm by 305 mm) continuous footing or turned-down slab edge is permitted at door openings in the braced wall line. This continuous footing or turned-down slab edge shall be reinforced with not less than one No. 4 bar top and bottom. This reinforcement shall be lapped not less than 15 inches (381 mm) with the reinforcement required in the continuous foundation located directly under the braced wall line.
Where a PFH is installed at the first story of two-story buildings, each panel shall have a length of not less than 24 inches (610 mm).
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound = 4.448 N.
Figure 2308.6.5.2 Portal Frame with Hold-Downs (pfh)
2308.6.6 Cripple wall bracing.
Cripple walls shall be braced in accordance with Section 2308.6.6.1 or 2308.6.6.2.
2308.6.6.1 Cripple wall bracing in Seismic Design Categories A, B and C.
For the purposes of this section, cripple walls in Seismic Design Categories A, B and C having a stud height exceeding 14 inches (356 mm) shall be considered a story and shall be braced in accordance with Table 2308.6.1. Spacing of edge nailing for required cripple wall bracing shall not exceed 6 inches (152 mm) on center along the foundation plate and the top plate of the cripple wall. Nail size, nail spacing for field nailing and more restrictive boundary nailing requirements shall be as required elsewhere in the code for the specific bracing material used.
2308.6.6.2 Cripple wall bracing in Seismic Design Category D.
For the purposes of this section, cripple walls in Seismic Design Category D having a stud height exceeding 14 inches (356 mm) shall be considered a story and shall be braced in accordance with Table 2308.6.1. Where interior braced wall lines occur without a continuous foundation below, the length of parallel exterior cripple wall bracing shall be one and one-half times the lengths required by Table 2308.6.1. Where the cripple wall sheathing type used is Method WSP or DWB and this additional length of bracing cannot be provided, the capacity of WSP or DWB sheathing shall be increased by reducing the spacing of fasteners along the perimeter of each piece of sheathing to 4 inches (102 mm) on center.
2308.6.7 Connections of braced wall panels.
Braced wall panel joints shall occur over studs or blocking. Braced wall panels shall be fastened to studs, top and bottom plates and at panel edges. Braced wall panels shall be applied to nominal 2-inch-wide (actual 1 1/2-inch (38 mm)) or larger stud framing.
2308.6.7.1 Bottom plate connection.
Braced wall line bottom plates shall be connected to joists or full-depth blocking below in accordance with Table 2304.10.1, or to foundations in accordance with Section 2308.6.7.3.
2308.6.7.2 Top plate connection.
Where joists or rafters are used, braced wall line top plates shall be fastened over the full length of the braced wall line to joists, rafters, rim boards or full-depth blocking above in accordance with Table 2304.10.1, as applicable, based on the orientation of the joists or rafters to the braced wall line. Blocking shall be not less than 2 inches (51 mm) in nominal thickness and shall be fastened to the braced wall line top plate as specified in Table 2304.10.1. Notching or drilling of holes in blocking in accordance with the requirements of Section 2308.4.2.4 or 2308.7.4 shall be permitted.
At exterior gable end walls, braced wall panel sheathing in the top story shall be extended and fastened to the roof framing where the spacing between parallel exterior braced wall lines is greater than 50 feet (15 240 mm).
Where roof trusses are used and are installed perpendicular to an exterior braced wall line, lateral forces shall be transferred from the roof diaphragm to the braced wall over the full length of the braced wall line by blocking of the ends of the trusses or by other approved methods providing equivalent lateral force transfer. Blocking shall be not less than 2 inches (51 mm) in nominal thickness and equal to the depth of the truss at the wall line and shall be fastened to the braced wall line top plate as specified in Table 2304.10.1. Notching or drilling of holes in blocking in accordance with the requirements of Section 2308.4.2.4 or 2308.7.4 shall be permitted.
Exception: Where the roof sheathing is greater than 9 1/4 inches (235 mm) above the top plate, solid blocking is not required where the framing members are connected using one of the following methods:
1. In accordance with Figure 2308.6.7.2(1).
2. In accordance with Figure 2308.6.7.2(2).
3. Full-height engineered blocking panels designed for values listed in AWC WFCM.
4. A design in accordance with accepted engineering methods.
For SI: 1 foot = 304.8 mm.
Figure 2308.6.7.2(1) Braced Wall Line Top Plate Connection
For SI: 1 foot = 304.8 mm.
Figure 2308.6.7.2(2) Braced Wall Panel Top Plate Connection
2308.6.7.3 Sill anchorage.
Where foundations are required by Section 2308.6.8, braced wall line sills shall be anchored to concrete or masonry foundations. Such anchorage shall conform to the requirements of Section 2308.3. The anchors shall be distributed along the length of the braced wall line. Other anchorage devices having equivalent capacity are permitted.
2308.6.7.4 Anchorage to all-wood foundations.
Where all-wood foundations are used, the force transfer from the braced wall lines shall be determined based on calculation and shall have a capacity that is not less than the connections required by Section 2308.3.
2308.6.8 Braced wall line and diaphragm support.
Braced wall lines and floor and roof diaphragms shall be supported in accordance with this section.
2308.6.8.1 Foundation requirements.
Braced wall lines shall be supported by continuous foundations.
Exception: For structures with a maximum plan dimension not more than 50 feet (15 240 mm), continuous foundations are required at exterior walls only.
For structures in Seismic Design Category D, exterior braced wall panels shall be in the same plane vertically with the foundation or the portion of the structure containing the offset shall be designed in accordance with accepted engineering practice and Section 2308.1.1.
Exceptions:
1. Exterior braced wall panels shall be permitted to be located not more than 4 feet (1219 mm) from the foundation below where supported by a floor constructed in accordance with all of the following:
1.1. Cantilevers or setbacks shall not exceed four times the nominal depth of the floor joists.
1.2. Floor joists shall be 2 inches by 10 inches (51 mm by 254 mm) or larger and spaced not more than 16 inches (406 mm) on center.
1.3. The ratio of the back span to the cantilever shall be not less than 2 to 1.
1.4. Floor joists at ends of braced wall panels shall be doubled.
1.5. A continuous rim joist shall be connected to the ends of cantilevered joists. The rim joist is permitted to be spliced using a metal tie not less than 0.058 inch (1.47 mm) (16 galvanized gage), 1 1/2 inches (38 mm) in width and 12 inches (305 mm) in length, fastened with six 16d common nails on each side. The metal tie shall have a yield stress not less than 33,000 psi (227 MPa).
1.6. Joists at setbacks or the end of cantilevered joists shall not carry gravity loads from more than a single story having uniform wall and roof loads nor carry the reactions from headers having a span of 8 feet (2438 mm) or more.
2. The end of a required braced wall panel shall be allowed to extend not more than 1 foot (305 mm) over an opening in the wall below. This requirement is applicable to braced wall panels offset in plane and braced wall panels offset out of plane as permitted by Exception 1. Braced wall panels are permitted to extend over an opening not more than 8 feet (2438 mm) in width where the header is a 4-inch by 12-inch (102 mm by 305 mm) or larger member.
2308.6.8.2 Floor and roof diaphragm support in Seismic Design Category D.
In structures assigned to Seismic Design Category D, floor and roof diaphragms shall be laterally supported by braced wall lines on all edges and connected in accordance with Section 2308.6.7 (see Figure 2308.6.8.2(1)).
Exception: Portions of roofs or floors that do not support braced wall panels above are permitted to extend up to 6 feet (1829 mm) beyond a braced wall line (see Figure 2308.6.8.2(2)) provided that the framing members are connected to the braced wall line below in accordance with Section 2308.6.7.
Figure 2308.6.8.2(1) Roof in SDC D Not Supported on All Edges
For SI: 1 foot = 304.8 mm.
Figure 2308.6.8.2(2) Roof Extension in SDC D Beyond Braced Wall Line
2308.6.8.3 Stepped footings in Seismic Design Categories B, C and D.
In Seismic Design Categories B, C and D, where the height of a required braced wall panel extending from foundation to floor above varies more than 4 feet (1219 mm), the following construction shall be used:
1. Where the bottom of the footing is stepped and the lowest floor framing rests directly on a sill bolted to the footings, the sill shall be anchored as required in Section 2308.3.
2. Where the lowest floor framing rests directly on a sill bolted to a footing not less than 8 feet (2438 mm) in length along a line of bracing, the line shall be considered to be braced. The double plate of the cripple stud wall beyond the segment of footing extending to the lowest framed floor shall be spliced to the sill plate with metal ties, one on each side of the sill and plate. The metal ties shall be not less than 0.058 inch (1.47 mm) (16 galvanized gage) by 1 1/2 inches (38 mm) in width by 48 inches (1219 mm) with eight 16d common nails on each side of the splice location (see Figure 2308.6.8.3). The metal tie shall have a yield stress not less than 33,000 psi (227 MPa).
3. Where cripple walls occur between the top of the footing and the lowest floor framing, the bracing requirements for a story shall apply.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
Figure 2308.6.8.3 Stepped Footing Connection Details
2308.6.9 Attachment of sheathing.
Fastening of braced wall panel sheathing shall be not less than that prescribed in Tables 2308.6.1 and 2304.10.1. Wall sheathing shall not be attached to framing members by adhesives.
2308.6.10 Limitations of concrete or masonry veneer.
Concrete or masonry veneer shall comply with Chapter 14 and this section.
2308.6.10.1 Limitations of concrete or masonry veneer in Seismic Design Categories B and C.
In Seismic Design Categories B and C, concrete or masonry walls and stone or masonry veneer shall not extend above a basement.
Exceptions:
1. In structures assigned to Seismic Design Category B, stone and masonry veneer is permitted to be used in the first two stories above grade plane or the first three stories above grade plane where the lowest story has concrete or masonry walls, provided that wood structural panel wall bracing is used and the length of bracing provided is one and one-half times the required length specified in Table 2308.6.1.
2. Stone and masonry veneer is permitted to be used in the first story above grade plane or the first two stories above grade plane where the lowest story has concrete or masonry walls.
3. Stone and masonry veneer is permitted to be used in both stories of buildings with two stories above grade plane, provided the following criteria are met:
3.1. Type of brace in accordance with Section 2308.6.1 shall be WSP and the allowable shear capacity in accordance with Section 2306.3 shall be not less than 350 plf (5108 N/m).
3.2. Braced wall panels in the second story shall be located in accordance with Section 2308.6.1 and not more than 25 feet (7620 mm) on center, and the total length of braced wall panels shall be not less than 25 percent of the braced wall line length. Braced wall panels in the first story shall be located in accordance with Section 2308.6.1 and not more than 25 feet (7620 mm) on center, and the total length of braced wall panels shall be not less than 45 percent of the braced wall line length.
3.3. Hold-down connectors with an allowable capacity of 2,000 pounds (8896 N) shall be provided at the ends of each braced wall panel for the second story to the first story connection. Hold-down connectors with an allowable capacity of 3,900 pounds (17 347 N) shall be provided at the ends of each braced wall panel for the first story to the foundation connection. In all cases, the hold-down connector force shall be transferred to the foundation.
3.4. Cripple walls shall not be permitted.
2308.6.10.2 Limitations of concrete or masonry in Seismic Design Category D.
In Seismic Design Category D, concrete or masonry walls and stone or masonry veneer shall not extend above a basement.
Exception: Stone and masonry veneer is permitted to be used in the first story above grade plane, provided the following criteria are met:
1. Type of brace in accordance with Section 2308.6.1 shall be WSP and the allowable shear capacity in accordance with Section 2306.3 shall be not less than 350 plf (5108 N/m).
2. The braced wall panels in the first story shall be located at each end of the braced wall line and not more than 25 feet (7620 mm) on center, and the total length of braced wall panels shall be not less than 45 percent of the braced wall line length.
3. Hold-down connectors shall be provided at the ends of braced walls for the first floor to foundation with an allowable capacity of 2,100 pounds (9341 N).
4. Cripple walls shall not be permitted.
2308.7 Roof and ceiling framing.
The framing details required in this section apply to roofs having a slope of not less than three units vertical in 12 units horizontal (25-percent slope). 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.
2308.7.1 Ceiling joist spans.
Spans for ceiling joists shall be in accordance with Table 2308.7.1(1) or 2308.7.1(2). For other grades and species, and other loading conditions, refer to the AWC STJR.
Table 2308.7.1(1) Ceiling Joist Spans for Common Lumber Species (Uninhabitable Attics Without Storage, Live Load = 10 psf, L/
D
= 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
12-5
19-6
25-8
Note a
Southern Pine
#2
11-10
18-8
24-7
Note a
Southern Pine
#3
10-1
14-11
18-9
22-9
Spruce-Pin e-Fir
SS
12-2
19-1
25-2
Note a
Spruce-Pin e-Fir
#1
11-10
18-8
24-7
Note a
Spruce-Pin e-Fir
#2
11-10
18-8
24-7
Note a
Spruce-Pin e-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
11-3
17-8
23-4
Note a
Southern Pine
#2
10-9
16-11
21-7
25-7
Southern Pine
#3
8-9
12-11
16-3
19-9
Spruce-Pin e-Fir
SS
11-0
17-4
22-10
Note a
Spruce-Pin e-Fir
#1
10-9
16-11
22-4
Note a
Spruce-Pin e-Fir
#2
10-9
16-11
22-4
Note a
Spruce-Pin e-Fir
#3
9-5
13-9
17-5
21-3
19.2
Douglas Fir-Larch
SS
11-3
17-8
23-3
Note a
Douglas Fir-Larch
#1
10-10
17-0
22-5
Note a
Douglas Fir-Larch
#2
10-7
16-7
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
10-7
16-8
22-0
Note a
Southern Pine
#2
10-2
15-7
19-8
23-5
Southern Pine
#3
8-0
11-9
14-10
18-0
Spruce-Pin e-Fir
SS
10-4
16-4
21-6
Note a
Spruce-Pin e-Fir
#1
10-2
15-11
21-0
25-8
Spruce-Pin e-Fir
#2
10-2
15-11
21-0
25-8
Spruce-Pin e-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
9-10
15-6
20-5
24-0
Southern Pine
#2
9-3
13-11
17-7
20-11
Southern Pine
#3
7-2
10-6
13-3
16-1
Spruce-Pin e-Fir
SS
9-8
15-2
19-11
25-5
Spruce-Pin e-Fir
#1
9-5
14-9
18-9
22-11
Spruce-Pin e-Fir
#2
9-5
14-9
18-9
22-11
Spruce-Pin e-Fir
#3
7-8
11-2
14-2
17-4
Check sources for availability of lumber in lengths greater than 20 feet.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
a. Span exceeds 26 feet in length.
Table 2308.7.1(2) Ceiling Joist Spans for Common Lumber Species (Uninhabitable Attics With Limited Storage, Live Load = 20 psf, L/
D
= 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
9-10
15-6
20-5
24-0
Southern Pine
#2
9-3
13-11
17-7
20-11
Southern Pine
#3
7-2
10-6
13-3
16-1
Spruce-Pin e-Fir
SS
9-8
15-2
19-11
25-5
Spruce-Pin e-Fir
#1
9-5
14-9
18-9
22-11
Spruce-Pin e-Fir
#2
9-5
14-9
18-9
22-11
Spruce-Pin e-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
8-11
14-0
17-9
20-9
Southern Pine
#2
8-0
12-0
15-3
18-1
Southern Pine
#3
6-2
9-2
11-6
14-0
Spruce-Pin e-Fir
SS
8-9
13-9
18-1
23-1
Spruce-Pin e-Fir
#1
8-7
12-10
16-3
19-10
Spruce-Pin e-Fir
#2
8-7
12-10
16-3
19-10
Spruce-Pin e-Fir
#3
6-8
9-8
12-4
15-0
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
18-2
23-1
Southern Pine
#1
8-5
12-9
16-2
18-11
Southern Pine
#2
7-4
11-0
13-11
16-6
Southern Pine
#3
5-8
8-4
10-6
12-9
Spruce-Pin e-Fir
SS
8-3
12-11
17-1
21-8
Spruce-Pin e-Fir
#1
8-0
11-9
14-10
18-2
Spruce-Pin e-Fir
#2
8-0
11-9
14-10
18-2
Spruce-Pin e-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
7-8
11-5
14-6
16-11
Southern Pine
#2
6-7
9-10
12-6
14-9
Southern Pine
#3
5-1
7-5
9-5
11-5
Spruce-Pin e-Fir
SS
7-8
12-0
15-10
19-5
Spruce-Pin e-Fir
#1
7-2
10-6
13-3
16-3
Spruce-Pin e-Fir
#2
7-2
10-6
13-3
16-3
Spruce-Pin e-Fir
#3
5-5
7-11
10-0
12-3
Check sources for availability of lumber in lengths greater than 20 feet.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
a. Span exceeds 26 feet in length.
2308.7.2 Rafter spans.
Spans for rafters shall be in accordance with Table 2308.7.2(1), 2308.7.2(2), 2308.7.2(3), 2308.7.2(4), 2308.7.2(5), or 2308.7.2(6). For other grades and species and other loading conditions, refer to the AWC STJR. The span of each rafter shall be measured along the horizontal projection of the rafter.
Table 2308.7.2(1) Rafter Spans for Common Lumber Species (Roof Live Load = 20 psf, Ceiling Not Attached to Rafters, L/
D
= 180)
Rafter Spacing (inches)
Species and Grade
Dead Load = 10 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
a
(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 b
Note b
11-6
18-0
18-0
Note b
Note b
Douglas Fir-Larch #1
11-1
17-4
22-5
Note b
Note b
10-6
15-4
15-4
23-9
Note b
Douglas Fir-Larch #2
10-10
16-7
21-0
25-8
Note b
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 b
Note b
10-10
17-0
22-5
Note b
Note b
Hem-Fir #1
10-7
16-8
21-10
Note b
Note b
10-3
14-11
18-11
23-2
Note b
Hem-Fir #2
10-1
15-11
20-8
25-3
Note b
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 b
Note b
11-3
17-8
23-4
Note b
Note b
Southern Pine #1
10-10
17-0
22-5
26-0
26-0
10-6
15-8
19-10
23-2
Note b
Southern Pine #2
10-4
15-7
19-8
23-5
26-0
9-0
13-6
17-1
20-3
23-10
Southern Pine #3
8-0
11-9
14-10
18-0
21-4
6-11
10-2
12-10
15-7
18-6
Spruce-Pine-Fir SS
10-7
16-8
21-11
Note b
Note b
10-7
16-8
21-9
Note b
Note b
Spruce-Pine-Fir #1
10-4
16-3
21-0
25-8
Note b
9-10
14-4
18-2
22-3
25-9
Spruce-Pine-Fir #2
10-4
16-3
21-0
25-8
Note b
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 b
Note b
10-5
16-0
20-3
24-9
Note b
Douglas Fir-Larch #1
10-0
15-4
19-5
23-9
Note b
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 b
Note b
9-10
15-6
19-11
24-4
Note b
Hem-Fir #1
9-8
14-11
18-11
23-2
Note b
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 b
Note b
10-3
16-1
21-2
25-7
Note b
Southern Pine #1
9-10
15-6
19-10
23-2
26-0
9-1
13-7
17-2
20-1
23-10
Southern Pine #2
9-0
13-6
17-1
20-3
23-10
7-9
11-8
14-9
17-6
20-8
Southern Pine #3
6-11
10-2
12-10
15-7
18-6
6-0
8-10
11-2
13-6
16-0
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
19.2
Douglas Fir-Larch SS
9-10
15-5
20-4
25-11
Note b
9-10
14-7
18-6
22-7
Note b
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
167
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 b
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 b
9-8
15-2
19-11
25-5
Note b
Southern Pine #1
9-3
14-3
18-1
21-2
25-2
8-4
12-4
15-8
18-4
21-9
Southern Pine #2
8-2
12-3
15-7
18-6
21-9
7-1
10-8
13-6
16-0
18-10
Southern Pine #3
6-4
9-4
11-9
14-3
16-10
5-6
8-1
10-2
12-4
14-7
Spruce-Pine-Fir SS
9-1
14-3
18-9
23-11
Note b
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 b
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 b
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 b
8-11
14-1
18-6
22-11
Note b
Southern Pine #1
8-7
12-9
16-2
18-11
22-6
7-5
11-1
14-0
16-5
19-6
Southern Pine #2
7-4
11-0
13-11
16-6
19-6
6-4
9-6
12-1
14-4
16-10
Southern Pine #3
5-8
8-4
10-6
12-9
15-1
4-11
7-3
9-1
11-0
13-1
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
138
15-11
5-3
7-8
9-9
11-10
13-9
Check sources for availability of lumber in lengths greater than 20 feet.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:
H
c
/H
R
Rafter Span Adjustment Factor
1/3
0.67
1/4
0.76
1/5
0.83
1/6
0.90
1/7.5 or less
1.00
where:
H
c
= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.
H
R
= Height of roof ridge measured vertically above the top of the rafter support walls.
b. Span exceeds 26 feet in length.
Table 2308.7.2(2) Rafter Spans for Common Lumber Species (Roof Live Load = 20 psf, Ceiling Attached to Rafters, L/
D
= 240)
Rafter Spacing (inches)
Species and Grade
Dead Load = 10 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
a
(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 b
Note b
10-5
16-4
21-7
Note b
Note b
Douglas Fir-Larch #1
10-0
15-9
20-10
Note b
Note b
10-0
15-4
19-5
23-9
Note b
Douglas Fir-Larch #2
9-10
15-6
20-5
25-8
Note b
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 b
Note b
9-10
15-6
20-5
Note b
Note b
Hem-Fir #1
9-8
15-2
19-11
25-5
Note b
9-8
14-11
18-11
23-2
Note b
Hem-Fir #2
9-2
14-5
19-0
24-3
Note b
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 b
Note b
10-3
16-1
21-2
Note b
Note b
Southern Pine #1
9-10
15-6
20-5
26-0
26-0
9-10
15-6
19-10
23-2
26-0
Southern Pine #2
9-5
14-9
19-6
23-5
26-0
9-0
13-6
17-1
20-3
23-10
Southern Pine #3
8-0
11-9
14-10
18-0
21-4
6-11
10-2
12-10
15-7
18-6
Spruce-Pine-Fir SS
9-8
15-2
19-11
25-5
Note b
9-8
15-2
19-11
25-5
Note b
Spruce-Pine-Fir #1
9-5
14-9
19-6
24-10
Note b
9-5
14-4
18-2
22-3
25-9
Spruce-Pine-Fir #2
9-5
14-9
19-6
24-10
Note b
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 b
9-6
14-11
19-7
24-9
Note b
Douglas Fir-Larch #1
9-1
14-4
18-11
23-9
Note b
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 b
8-11
14-1
18-6
23-8
Note b
Hem-Fir #1
8-9
13-9
18-1
23-1
Note b
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 b
9-4
14-7
19-3
24-7
Note b
Southern Pine #1
8-11
14-1
18-6
23-2
26-0
8-11
13-7
17-2
20-1
23-10
Southern Pine #2
8-7
13-5
17-1
20-3
23-10
7-9
11-8
14-9
17-6
20-8
Southern Pine #3
6-11
10-2
12-10
15-7
18-6
6-0
8-10
11-2
13-6
16-0
Spruce-Pine-Fir SS
8-9
13-9
18-1
23-1
Note b
8-9
13-9
18-1
23-0
Note b
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
19.2
Douglas Fir-Larch SS
8-11
14-0
18-5
23-7
Note b
8-11
14-0
18-5
22-7
Note b
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
17-3
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 b
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 b
8-9
13-9
18-1
23-1
Note b
Southern Pine #1
8-5
13-3
17-5
21-2
25-2
8-4
12-4
15-8
18-4
21-9
Southern Pine #2
8-1
12-3
15-7
18-6
21-9
7-1
10-8
13-6
16-0
18-10
Southern Pine #3
6-4
9-4
11-9
14-3
16-10
5-6
8-1
10-2
12-4
14-7
Spruce-Pine-Fir SS
8-3
12-11
17-1
21-9
Note b
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 b
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
23-3
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 b
8-1
12-9
16-10
21-6
Note b
Southern Pine #1
7-10
12-3
16-2
18-11
22-6
7-5
11-1
14-0
16-5
19-6
Southern Pine #2
7-4
11-0
13-11
16-6
19-6
6-4
9-6
12-1
14-4
16-10
Southern Pine #3
5-8
8-4
10-6
12-9
15-1
4-11
7-3
9-1
11-0
13-1
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
Check sources for availability of lumber in lengths greater than 20 feet.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:
H
c
/H
R
Rafter Span Adjustment Factor
1/3
0.67
1/4
0.76
1/5
0.83
1/6
0.90
1/7.5 or less
1.00
where:
H
c
= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.
H
R
= Height of roof ridge measured vertically above the top of the rafter support walls.
b. Span exceeds 26 feet in length.
Table 2308.7.2(3) Rafter Spans for Common Lumber Species (Ground Snow Load = 30 psf, Ceiling Not Attached to Rafters, L/
D
= 180)
Rafter Spacing (inches)
Species and Grade
Dead Load = 10 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
a
(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 b
Note b
10-0
15-9
20-1
24-6
Note b
Douglas Fir-Larch #1
9-8
14-9
18-8
22-9
Note b
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 b
9-6
14-10
19-7
24-1
Note b
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 b
Note b
9-10
15-6
20-5
Note b
Note b
Southern Pine #1
9-6
14-10
19-0
22-3
26-0
9-0
13-5
17-0
19-11
23-7
Southern Pine #2
8-7
12-11
16-4
19-5
22-10
7-8
11-7
14-8
17-4
20-5
Southern Pine #3
6-7
9-9
12-4
15-0
17-9
5-11
8-9
11-0
13-5
15-10
Spruce-Pine-Fir SS
9-3
14-7
19-2
24-6
Note b
9-3
14-7
18-8
22-9
Note b
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 b
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 b
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 b
8-11
14-1
18-6
23-8
Note b
Southern Pine #1
8-7
13-0
16-6
19-3
22-10
7-10
11-7
14-9
17-3
20-5
Southern Pine #2
7-6
11-2
14-2
16-10
19-10
6-8
10-0
12-8
15-1
17-9
Southern Pine #3
5-9
8-6
10-8
13-0
15-4
5-2
7-7
9-7
11-7
13-9
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
7-2
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
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 b
8-5
13-3
17-5
22-0
25-9
Southern Pine #1
8-0
11-10
15-1
17-7
20-11
7-1
10-7
13-5
15-9
18-8
Southern Pine #2
6-10
10-2
12-11
15-4
18-1
6-1
9-2
11-7
13-9
16-2
Southern Pine #3
5-3
7-9
9-9
11-10
14-0
4-8
6-11
8-9
10-7
12-6
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
7-1
10-7
13-5
15-9
18-8
6-4
9-6
12-0
14-1
16-8
Southern Pine #2
6-1
9-2
11-7
13-9
16-2
5-5
8-2
10-4
12-3
14-6
Southern Pine #3
4-8
6-11
8-9
10-7
12-6
4-2
6-2
7-10
9-6
11-2
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
Check sources for availability of lumber in lengths greater than 20 feet.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:
H
c
/H
R
Rafter Span Adjustment Factor
1/3
0.67
1/4
0.76
1/5
0.83
1/6
0.90
1/7.5 or less
1.00
where:
H
c
= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.
H
R
= Height of roof ridge measured vertically above the top of the rafter support walls.
b. Span exceeds 26 feet in length.
Table 2308.7.2(4) Rafter Spans for Common Lumber Species (Ground Snow Load = 50 psf, Ceiling Not Attached to Rafters, L/
D
= 180)
Rafter Spacing (inches)
Species and Grade
Dead Load = 10 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
a
(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
13-1
17-2
21-11
Note b
8-4
13-1
17-2
21-5
25-3
Southern Pine #1
8-0
12-3
15-6
18-2
21-7
7-7
11-4
14-5
16-10
20-0
Southern Pine #2
7-0
10-6
13-4
15-10
18-8
6-6
9-9
12-4
14-8
17-3
Southern Pine #3
5-5
8-0
10-1
12-3
14-6
5-0
7-5
9-4
11-4
13-5
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
13-3
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
23-7
7-6
11-10
15-7
18-6
21-10
Southern Pine #1
7-1
10-7
13-5
15-9
18-8
6-7
9-10
12-5
14-7
17-3
Southern Pine #2
6-1
9-2
11-7
13-9
16-2
5-8
8-5
10-9
12-9
15-0
Southern Pine #3
4-8
6-11
8-9
10-7
12-6
4-4
6-5
8-1
9-10
11-7
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
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
18-3
21-7
7-1
11-2
14-2
16-11
20-0
Southern Pine #1
6-6
9-8
12-3
14-4
17-1
6-0
9-0
11-4
13-4
15-9
Southern Pine #2
5-7
8-4
10-7
12-6
14-9
5-2
7-9
9-9
11-7
13-8
Southern Pine #3
4-3
6-4
8-0
9-8
11-5
4-0
5-10
7-4
8-11
10-7
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
16-4
19-3
6-7
10-0
13-8
15-2
17-10
Southern Pine #1
5-10
8-8
11-0
12-10
15-3
5-5
8-0
10-2
11-11
14-1
Southern Pine #2
5-0
7-5
9-5
11-3
13-2
4-7
6-11
8-9
10-5
12-3
Southern Pine #3
3-10
5-8
7-1
8-8
10-3
3-6
5-3
6-7
8-0
9-6
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
Check sources for availability of lumber in lengths greater than 20 feet.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:
H
c
/H
R
Rafter Span Adjustment Factor
1/3
0.67
1/4
0.76
1/5
0.83
1/6
0.90
1/7.5 or less
1.00
where:
H
c
= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.
H
R
= Height of roof ridge measured vertically above the top of the rafter support walls.
b. Span exceeds 26 feet in length.
Table 2308.7.2(5) Rafter Spans for Common Lumber Species (Ground Snow Load = 30 psf, Ceiling Attached to Rafters, L/
D
= 240)
Rafter Spacing (inches)
Species and Grade
Dead Load = 10 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
a
(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 b
9-1
14-4
18-10
24-1
Note b
Douglas Fir-Larch #1
8-9
13-9
18-2
22-9
Note b
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 b
8-7
13-6
17-10
22-9
Note b
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 b
8-11
14-1
18-6
23-8
Note b
Southern Pine #1
8-7
13-6
17-10
22-3
Note b
8-7
13-5
17-0
19-11
23-7
Southern Pine #2
8-3
12-11
16-4
19-5
22-10
7-8
11-7
14-8
17-4
20-5
Southern Pine #3
6-7
9-9
12-4
15-0
17-9
5-11
8-9
11-0
13-5
15-10
Spruce-Pine-Fir SS
8-5
13-3
17-5
22-3
Note b
8-5
13-3
17-5
22-3
Note b
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 b
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 b
8-1
12-9
16-10
21-6
Note b
Southern Pine #1
7-10
12-3
16-2
19-3
22-10
7-10
11-7
14-9
17-3
20-5
Southern Pine #2
7-6
11-2
14-2
16-10
19-10
6-8
10-0
12-8
15-1
17-9
Southern Pine #3
5-9
8-6
10-8
13-0
15-4
5-2
7-7
9-7
11-7
13-9
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-Fir #2
7-6
11-9
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
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
9-1
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
7-4
11-7
15-1
17-7
20-11
7-1
10-7
13-5
15-9
18-8
Southern Pine #2
6-10
10-2
12-11
15-4
18-1
6-1
9-2
11-7
13-9
16-2
Southern Pine #3
5-3
7-9
9-9
11-10
14-0
4-8
6-11
8-9
10-7
12-6
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
13-5
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
6-10
10-7
13-5
15-9
18-8
6-4
9-6
12-0
14-1
16-8
Southern Pine #2
6-1
9-2
11-7
13-9
16-2
5-5
8-2
10-4
12-3
14-6
Southern Pine #3
4-8
6-11
8-9
10-7
12-6
4-2
6-2
7-10
9-6
11-2
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
Check sources for availability of lumber in lengths greater than 20 feet.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:
H
c
/H
R
Rafter Span Adjustment Factor
1/3
0.67
1/4
0.76
1/5
0.83
1/6
0.90
1/7.5 or less
1.00
where:
H
c
= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.
H
R
= Height of roof ridge measured vertically above the top of the rafter support walls.
b. Span exceeds 26 feet in length.
Table 2308.7.2(6) Rafter Spans for Common Lumber Species (Ground Snow Load = 50 psf, Ceiling Attached to Rafters, L/
D
= 240)
Rafter Spacing (inches)
Species and Grade
Dead Load = 10 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
a
(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
14-0
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
11-8
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
11-10
15-7
19-11
24-3
7-6
11-10
15-7
19-11
24-3
Southern Pine #1
7-3
11-5
15-0
18-2
21-7
7-3
11-4
14-5
16-10
20-0
Southern Pine #2
6-11
10-6
13-4
15-10
18-8
6-6
9-9
12-4
14-8
17-3
Southern Pine #3
5-5
8-0
10-1
12-3
14-6
5-0
7-5
9-4
11-4
13-5
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
21-10
Southern Pine #1
6-7
10-4
13-5
15-9
18-8
6-7
9-10
12-5
14-7
17-3
Southern Pine #2
6-1
9-2
11-7
13-9
16-2
5-8
8-5
10-9
12-9
15-0
Southern Pine #3
4-8
6-11
8-9
10-7
12-6
4-4
6-5
8-1
9-10
11-7
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
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
16-11
20-0
Southern Pine #1
6-2
9-8
12-3
14-4
17-1
6-0
9-0
11-4
13-4
15-9
Southern Pine #2
5-7
8-4
10-7
12-6
14-9
5-2
7-9
9-9
11-7
13-8
Southern Pine #3
4-3
6-4
8-0
9-8
11-5
4-0
5-10
7-4
8-11
10-7
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 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
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
6-10
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
15-2
17-10
Southern Pine #1
5-9
8-8
11-0
12-10
15-3
5-5
8-0
10-2
11-11
14-1
Southern Pine #2
5-0
7-5
9-5
11-3
13-2
4-7
6-11
8-9
10-5
12-3
Southern Pine #3
3-10
5-8
7-1
8-8
10-3
3-6
5-3
6-7
8-0
9-6
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
Check sources for availability of lumber in lengths greater than 20 feet.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:
H
c
/H
R
Rafter Span Adjustment Factor
1/3
0.67
1/4
0.76
1/5
0.83
1/6
0.90
1/7.5 or less
1.00
where:
H
c
= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.
H
R
= Height of roof ridge measured vertically above the top of the rafter support walls.
2308.7.3 Ceiling joist and rafter framing.
Rafters shall be framed directly opposite each other at the ridge. There shall be a ridge board not less than 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.
2308.7.3.1 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 2304.10.1 and 2308.7.5. Ceiling joists shall be continuous or securely joined where they meet over interior partitions and be fastened to adjacent rafters in accordance with Tables 2304.10.1 and 2308.7.3.1 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 1 1/2 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) on center. The connections shall be in accordance with Tables 2304.10.1 and 2308.7.3.1, 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 2308.8. Rafter ties shall be spaced not more than 4 feet (1219 mm) on center.
Rafter tie connections shall be based on the equivalent rafter spacing in Table 2308.7.3.1. Rafter-to-ceiling joist connections and rafter tie connections shall be of sufficient size and number to prevent splitting from nailing.
Roof framing member connection to braced wall lines shall be in accordance with Section 2308.6.7.2.
Table 2308.7.3.1 Rafter Tie Connections
g
Rafter Slope
Tie Spacing (inches)
No Snow Load
Ground Snow Load (pounds 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 (3 1/2" × 0.162") nails
a, b
per connection
c, 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 16d sinker (3 1/4" × 0.148") nails are permitted to be substituted for 16d common (3 1/2" × 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.
2308.7.4 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 more than 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.
2308.7.5 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 2304.10.1 and 2308.7.5.
Table 2308.7.5 Required Rating of Approved Uplift Connectors (Pounds)
a, b, c, e, f, g, h
Allowable Stress Design Wind Speed, V
asd
i
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.
Exposure
Mean Roof Height (feet)
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 28.5-1 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 V
asd
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. V
asd
shall be determined in accordance with Section 1609.3.1.
2308.7.6 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 that are more than 6 feet (1829 mm) in length shall be supported by framing anchors or rafter hangers unless bearing on a beam, partition or wall.
2308.7.6.1 Openings in roof diaphragms in Seismic Design Categories B, C and D.
In buildings classified as Seismic Design Category B, C or D, openings in horizontal diaphragms with a dimension that is greater than 4 feet (1219 mm) shall be constructed with metal ties and blocking in accordance with this section and Figure 2308.4.4.1(1). Metal ties shall be not less than 0.058 inch (1.47 mm) (16 galvanized gage) in thickness by 1 1/2 inches (38 mm) in width and shall have a yield stress not less than 33,000 psi (227 Mpa). Blocking shall extend not less than the dimension of the opening in the direction of the tie and blocking. Ties shall be attached to blocking in accordance with the manufacturer's instructions but with not less than eight 16d common nails on each side of the header-joist intersection.
2308.7.7 Purlins.
Purlins to support roof loads are permitted to be installed to reduce the span of rafters within allowable limits and shall be supported by struts to bearing walls. The maximum span of a 2-inch by 4-inch (51 mm by 102 mm) purlin shall be 4 feet (1219 mm). The maximum span of a 2-inch by 6-inch (51 mm by 152 mm) purlin shall be 6 feet (1829 mm), but in no case shall the purlin be smaller than the supported rafter. Struts shall be not less than 2-inch by 4-inch (51 mm by 102 mm) members. The unbraced length of struts shall not exceed 8 feet (2438 mm) and the slope of the struts shall be not less than 45 degrees (0.79 rad) from the horizontal.
2308.7.8 Blocking.
Roof rafters and ceiling joists shall be supported laterally to prevent rotation and lateral displacement in accordance with Section 2308.4.6 and shall be connected to braced wall lines in accordance with Section 2308.6.7.2.
2308.7.9 Engineered wood products.
Prefabricated wood I-joists, structural glued-laminated timber and structural composite lumber shall not be notched or drilled except where permitted by the manufacturer's recommendations or where the effects of such alterations are specifically considered in the design of the member by a registered design professional.
2308.7.10 Roof sheathing.
Roof sheathing shall be in accordance with Tables 2304.8(3) and 2304.8(5) for wood structural panels, and Tables 2304.8(1) and 2304.8(2) for lumber and shall comply with Section 2304.8.2.
2308.7.11 Joints.
Joints in lumber sheathing shall occur over supports unless approved end-matched lumber is used, in which case each piece shall bear on at least two supports.
2308.7.12 Roof planking.
Planking shall be designed in accordance with the general provisions of this code.
In lieu of such design, 2-inch (51 mm) tongue-and-groove planking is permitted in accordance with Table 2308.7.12. 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 not less than 24 inches (610 mm) in adjacent pieces.
Table 2308.7.12 Allowable Spans for 2-Inch Tongue-and-Groove Decking
Span
a
(feet)
Live Load (pounds per square foot)
Deflection Limit
Bending Stress (
f
) (pounds per square inch)
Modulus of Elasticity (
E
) (pounds 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
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/m
2
, 1 pound per square inch = 0.00689 N/mm
2
.
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 2308.7.12. Lumber thickness is 1 1/2 inches actual.
2308.7.13 Wood trusses.
Wood trusses shall be designed in accordance with Section 2303.4. Connection to braced wall lines shall be in accordance with Section 2308.6.7.2.
2308.7.14 Attic ventilation.
For attic ventilation, see Section 1203.2. For provisions related to cutting and notching of members, see Section 2308.7.4.
2308.8 Design of elements.
Combining of engineered elements or systems and conventionally specified elements or systems shall be permitted subject to the limits of Sections 2308.8.1 and 2308.8.2.
2308.8.1 Elements exceeding limitations of conventional construction.
Where a building of otherwise conventional construction contains structural elements exceeding the limits of Section 2308.2, these elements and the supporting load path shall be designed in accordance with accepted engineering practice and the provisions of this code.
2308.8.2 Structural elements or systems not described herein.
Where a building of otherwise conventional construction contains structural elements or systems not described in Section 2308, these elements or systems shall be designed in accordance with accepted engineering practice and the provisions of this code. The extent of such design need only demonstrate compliance of the nonconventional elements with other applicable provisions of this code and shall be compatible with the performance of the conventionally framed system.
Collected 2026-09-06T02:48:57Z. Source file · JSON