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Structural sheathing shall be installed in accordance with Figure R603.9 and this section on all sheathable exterior wall surfaces, including areas above and below openings.

FIGURE R603.9
STRUCTURAL SHEATHING FASTENING PATTERN
R603.9.1 Sheathing Materials
Structural sheathing panels shall consist of minimum 7/16-inch-thick (11 mm) oriented strand board or 15/32-inch-thick (12 mm) plywood.
R603.9.2 Determination of Minimum Length of Full- Height Sheathing
The minimum length of full-height sheathing on each braced wall line shall be determined by multiplying the length of the braced wall line by the percentage obtained from Table R603.9.2(1) and by the plan aspect-ratio adjustment factors obtained from Table R603.9.2(2). The minimum length of full-height sheathing shall be not less than 20 percent of the braced wall line length.
To be considered full-height sheathing, structural sheathing shall extend from the bottom to the top of the wall without interruption by openings. Only sheathed, full-height wall sections, uninterrupted by openings, which are not less than 48 inches (1219 mm) wide, shall be counted toward meeting the minimum percentages in Table R603.9.2(1). In addition, structural sheathing shall comply with all of the following requirements:
  1. Be installed with the long dimension parallel to the stud framing and shall cover the full vertical height of wall from the bottom of the bottom track to the top of the top track of each story. Installing the long dimension perpendicular to the stud framing or using shorter segments shall be permitted provided that the horizontal joint is blocked as described in Item 2.
  2. Be blocked where the long dimension is installed perpendicular to the stud framing. Blocking shall be not less than 33 mil (0.84 mm) thickness. Each horizontal structural sheathing panel shall be fastened with No. 8 screws spaced at 6 inches (152 mm) on center to the blocking at the joint.
  3. Be applied to each end (corners) of each of the exterior walls with a minimum 48-inch-wide (1219 mm) panel.
Exception: Where stone or masonry veneer is installed, the required length of full-height sheathing and overturning anchorage required shall be determined in accordance with Section R603.9.5.

MINIMUM PERCENTAGE OF FULL-HEIGHT STRUCTURAL SHEATHING ON EXTERIOR WALLSa, b
WALL SUPPORTING ROOF SLOPE ULTIMATE WIND SPEED AND EXPOSURE (mph)
115 B 120 B 130 B < 140 B < 130 C < 140 C
115 C 120 C
Roof and ceiling only
(one story or top floor of two- or three-story building)
3:12 9 11 11 13 17 20
6:12 13 15 17 22 28 35
9:12 23 27 29 33 53 59
12:12 32 39 40 44 70 76
One story, roof and ceiling
(first floor of a two-story building or second floor of a three-story building)
3:12 26 32 34 39 53 67
6:12 27 33 34 44 61 75
9:12 38 45 46 61 78 92
12:12 43 53 57 72 106 116
Two stories, roof and ceiling
(first floor of a three-story building)
3:12 43 53 57 64 89 113
6:12 41 51 51 67 95 114
9:12 53 63 63 89 104 126
12:12 54 67 74 100 142 157
For SI: 1 mph = 0.447 m/s.
  1. Linear interpolation is permitted.
  2. For hip-roofed homes the minimum percentage of full-height sheathing, based on wind, is permitted to be multiplied by a factor of 0.95 for roof slopes not exceeding 7:12 and a factor of 0.9 for roof slopes greater than 7:12.
FULL-HEIGHT SHEATHING LENGTH ADJUSTMENT FACTORS
PLAN ASPECT RATIO LENGTH ADJUSTMENT FACTORS
Short wall Long wall
1:1 1.0 1.0
1.5:1 1.5 0.67
2:1 2.0 0.50
3:1 3.0 0.33
4:1 4.0 0.25
R603.9.2.1 Full-Height Sheathing
The minimum percentage of full-height structural sheathing shall be multiplied by 1.10 for 9-foot-high (2743 mm) walls and multiplied by 1.20 for 10-foot-high (3048 mm) walls.
R603.9.2.2 Full-Height Sheathing in Lowest Story
In the lowest story of a dwelling, multiplying the percentage of full-height sheathing required in Table R603.9.2(1) by 0.6 shall be permitted where hold-down anchors are provided in accordance with Section R603.9.4.2.
R603.9.3 Structural Sheathing Fastening
Edges and interior areas of structural sheathing panels shall be fastened to framing members and tracks in accordance with Figure R603.9 and Table R603.3.2(1). Screws for attachment of structural sheathing panels shall be bugle-head, flat-head, or similar head style with a minimum head diameter of 0.29 inch (8 mm).
For continuously sheathed braced wall lines using wood structural panels installed with No. 8 screws spaced 4 inches (102 mm) on center at all panel edges and 12 inches (304.8 mm) on center on intermediate framing members, the following shall apply:
  1. Multiplying the percentages of full-height sheathing in Table R603.9.2(1) by 0.72 shall be permitted.
  2. For bottom track attached to foundations or framing below, the bottom track anchor or screw connection spacing in Tables R505.3.1(1) and R603.3.1 shall be multiplied by two-thirds.
R603.9.4 Uplift Connection Requirements
Uplift connections shall be provided in accordance with this section.
R603.9.4.1 Ultimate Design Wind Speeds Greater Than 130 mph
Where ultimate design wind speeds exceed 130 miles per hour (58 m/s), Exposure Category C walls shall be provided with direct uplift connections in accordance with AISI S230, Section E13.3, and AISI S230, Section F8.2, as required for 140 miles per hour (63 m/s), Exposure Category C.
R603.9.4.2 Hold-Down Anchor
Where the percentage of full-height sheathing is adjusted in accordance with Section R603.9.2.2, a hold-down anchor, with a strength of 4,300 pounds (19 kN), shall be provided at each end of each full-height sheathed wall section used to meet the minimum percent sheathing requirements of Section R603.9.2. Hold-down anchors shall be attached to back-to-back studs; structural sheathing panels shall have edge fastening to the studs, in accordance with Section R603.9.3 and AISI S230, Table E11-1.
A single hold-down anchor, installed in accordance with Figure R603.9.4.2, shall be permitted at the corners of buildings.


For SI: 1 inch = 25.4 mm.
FIGURE R603.9.4.2
CORNER STUD HOLD-DOWN DETAIL
R603.9.5 Structural Sheathing for Stone and Masonry Veneer
Where stone and masonry veneer are installed in accordance with Section R703.8, the length of full-height sheathing for exterior and interior wall lines backing or perpendicular to and laterally supporting walls with veneer shall comply with this section.
TABLE R603.9.5(1)
REQUIRED LENGTH OF FULL-HEIGHT SHEATHING AND ASSOCIATED OVERTURNING ANCHORAGE FOR WALLS SUPPORTING WALLS WITH STONE OR MASONRY VENEER AND USING 33-MIL COLD-FORMED STEEL FRAMING AND 6-INCH SCREW SPACING ON THE PERIMETER OF EACH PANEL OF STRUCTURAL SHEATHING
SEISMIC DESIGN CATEGORY STORY BRACED WALL LINE LENGTH (feet) SINGLE-STORY HOLD-DOWN FORCE (pounds) CUMULATIVE HOLD-DOWN FORCE (pounds)
10 20 30 40 50 60
Minimum total length of braced wall panels required along each braced wall line (feet)
D0 3.3 4.7 6.1 7.4 8.8 10.2 3,360
5.3 8.7 12.1 15.4 18.8 22.2 3,360 6,720
7.3 12.7 18.0 23.4 28.8 34.2 3,360 10,080
D1 4.1 5.8 7.5 9.2 10.9 12.7 3,360
6.6 10.7 14.9 19.1 23.3 27.5 3,360 6,720
9.0 15.7 22.4 29.0 35.7 42.2 3,360 10,080
D2 5.7 8.2 10.6 13.0 15.4 17.8 3,360
9.2 15.1 21.1 27.0 32.9 38.8 3,360 6,720
12.7 22.1 31.5 40.9 50.3 59.7 3,360 10,080
For SI: 1 mil = 0.0254 mm, 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound-force = 4.448 N.

REQUIRED LENGTH OF FULL-HEIGHT SHEATHING AND ASSOCIATED OVERTURNING ANCHORAGE FOR WALLS SUPPORTING WALLS WITH STONE OR MASONRY VENEER AND USING 43-MIL COLD-FORMED STEEL FRAMING AND 6-INCH SCREW SPACING ON THE PERIMETER OF EACH PANEL OF STRUCTURAL SHEATHING
SEISMIC DESIGN CATEGORY STORY BRACED WALL LINE LENGTH (feet) SINGLE-STORY HOLD-DOWN FORCE (pounds) CUMULATIVE HOLD-DOWN FORCE (pounds)
10 20 30 40 50 60
Minimum total length of braced wall panels required along each braced wall line (feet)
D0 2.8 4.0 5.1 6.3 7.5 8.7 3,960
4.5 7.4 10.2 13.1 16.0 18.8 3,960 7,920
6.2 10.7 15.3 19.9 24.4 29.0 3,960 11, 880
D1 3.5 4.9 6.4 7.8 9.3 10.7 3,960
5.6 9.1 12.7 16.2 19.8 23.3 3,960 7,920
7.7 13.3 19.0 24.6 30.3 35.9 3,960 11, 880
D2 4.9 6.9 9.0 11.0 13.1 15.1 3,960
7.8 12.9 17.9 22.9 27.9 32.9 3,960 7,920
10.8 18.8 26.7 34.7 42.7 50.7 3,960 11, 880
For SI: 1 mil = 0.0254 mm, 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound-force = 4.448 N.

REQUIRED LENGTH OF FULL-HEIGHT SHEATHING AND ASSOCIATED OVERTURNING ANCHORAGE FOR WALLS SUPPORTING WALLS WITH STONE OR MASONRY VENEER AND USING 33-MIL COLD-FORMED STEEL FRAMING AND 4-INCH SCREW SPACING ON THE PERIMETER OF EACH PANEL OF STRUCTURAL SHEATHING
SEISMIC DESIGN CATEGORY STORY BRACED WALL LINE LENGTH (feet) SINGLE-STORY HOLD-DOWN FORCE (pounds) CUMULATIVE HOLD-DOWN FORCE (pounds)
10 20 30 40 50 60
Minimum total length of braced wall panels required along each braced wall line (feet)
D0 2.5 3.6 4.6 5.7 6.8 7.8 4,392
4.0 6.6 9.2 11.8 14.4 17.0 4,392 8,784
5.6 9.7 13.8 17.9 22.0 26.2 4,392 13,176
D1 3.1 4.4 5.7 7.1 8.4 9.7 4,392
5.0 8.2 11.4 14.6 17.8 21.0 4,392 8,784
6.9 12.0 17.1 22.2 27.3 32.4 4,392 13,176
D2 4.4 6.2 8.1 10.0 11.8 13.7 4,392
7.1 11.6 16.1 20.6 25.1 29.7 4,392 8,784
9.7 16.9 24.1 31.3 38.5 45.7 4,392 13,176
For SI: 1 mil = 0.0254 mm, 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound-force = 4.448 N.

REQUIRED LENGTH OF FULL-HEIGHT SHEATHING AND ASSOCIATED OVERTURNING ANCHORAGE FOR WALLS SUPPORTING WALLS WITH STONE OR MASONRY VENEER AND USING 43-MIL COLD-FORMED STEEL FRAMING AND 4-INCH SCREW SPACING ON THE PERIMETER OF EACH PANEL OF STRUCTURAL SHEATHING
SEISMIC DESIGN CATEGORY STORY BRACED WALL LINE LENGTH (feet) SINGLE-STORY HOLD-DOWN FORCE (pounds) CUMULATIVE HOLD-DOWN FORCE (pounds)
10 20 30 40 50 60
Minimum total length of braced wall panels required along each braced wall line (feet)
D0 1.9 2.7 3.4 4.2 5.0 5.8 5,928
3.0 4.9 6.8 8.8 10.7 12.6 5,928 11,856
D1 2.3 3.3 4.3 5.2 6.2 7.2 5,928
3.7 6.1 8.5 10.8 13.2 15.6 5,928 11,856
D2 3.3 4.6 6.0 7.4 8.7 10.1 5,928
5.2 8.6 11.9 15.3 18.6 22.0 5,928 11,856
For SI: 1 mil = 0.0254 mm, 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound-force = 4.448 N.
R603.9.5.1 Seismic Design Category C
In Seismic Design Category C, the length of structural sheathing for walls supporting one story, roof and ceiling shall be the greater of the amounts required by Section R603.9.2, except Section R603.9.2.2 shall be permitted.
R603.9.5.2 Seismic Design Categories D0, D1 and D2
In Seismic Design Categories D0, D1 and D2, the required length of structural sheathing and overturning anchorage shall be determined in accordance with Tables R603.9.5(1), R603.9.5(2), R603.9.5(3), and R603.9.5(4). Overturning anchorage shall be installed on the doubled studs at the end of each full-height wall segment.

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