Page 283 - 2018_IRC

WALL CONSTRUCTION

TABLE R603.9.2(1)
MINIMUM PERCENTAGE OF FULL-HEIGHT STRUCTURAL SHEATHING ON EXTERIOR WALLS a, b
ULTIMATE WIND SPEED AND EXPOSURE
(mph)
WALL SUPPORTING ROOF SLOPE 130 B < 140 B
115 B 120 B < 130 C < 140 C
115 C 120 C
3 : 1 2 9 1 1 1 1 1 3 1 7 2 0
Roof and ceiling only (one story or top 6:12 13 15 17 22 28 35
floor of two- or three-story building) 9:12 23 27 29 33 53 59
1 2 : 1 2 3 2 3 9 4 0 4 4 7 0 7 6
3:12 26 32 34 39 53 67
One story, roof and ceiling (first floor of a 6:12 27 33 34 44 61 75
two-story building or second floor of a
three-story building) 9:12 38 45 46 61 78 92
12:12 43 53 57 72 106 116
3:12 43 53 57 64 89 113
Two stories, roof and ceiling (first floor of 6:12 41 51 51 67 95 114
a three-story building) 9:12 53 63 63 89 104 126
12:12 54 67 74 100 142 157
For SI: 1 mph = 0.447 m/s.
a. Linear interpolation is permitted.
b. 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.

TABLE R603.9.2(2)
FULL-HEIGHT SHEATHING LENGTH ADJUSTMENT FACTORS
LENGTH ADJUSTMENT FACTORS
PLAN ASPECT RATIO
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

DOUBLE STUDS BACK-TO-BACK WITH DOUBLE ROW OF NO. 8 SCREWS
OUTSIDE STUD CAPPED WITH TRACK AT 12 IN. O.C.
NO. 8 SHEATHING ATTACHMENT HOLD DOWN AS REQUIRED BY
SCREWS AS REQUIRED BY SECTION R603.9.4
SECTION R603.9.3
NO. 8 SCREWS ATTACHING
TRACK TO STUD AT 8 IN.
O.C. EACH FLANGE

INSIDE FACE
PLYWOOD, OSB OR GWB WALLBOARD BACKING STUDS
SHEATHING PER SHEARWALL
REQUIREMENTS

OUTSIDE FACE INSIDE FACE

For SI: 1 inch = 25.4 mm.
FIGURE R603.9.4.2
CORNER STUD HOLD-DOWN DETAIL

258 2018 INTERNATIONAL RESIDENTIAL CODE ®
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