Page 282 - 2018_IRC

WALL CONSTRUCTION

STUD SPACING R603.9.2.1 Full height sheathing. The minimum per-
centage of full-height structural sheathing shall be mul-
tiplied 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 percent-
age 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.
WALL HEIGHT STRUCTURAL SHEATHING R603.9.3 Structural sheathing fastening. Edges and
interior areas of structural sheathing panels shall be fas-
PANEL
FIELD FASTENER tened to framing members and tracks in accordance with
Figure R603.9 and Table R603.3.2(1). Screws for attach-
EDGE FASTENER
ment of structural sheathing panels shall be bugle-head,
flat-head, or similar head style with a minimum head
FIGURE R603.9
STRUCTURAL SHEATHING FASTENING PATTERN diameter of 0.29 inch (8 mm).
For continuously sheathed braced wall lines using
R603.9.1 Sheathing materials. Structural sheathing pan- wood structural panels installed with No. 8 screws spaced
7
els shall consist of minimum / -inch-thick (11 mm) ori- 4 inches (102 mm) on center at all panel edges and 12
16
ented strand board or / -inch-thick (12 mm) plywood. inches (304.8 mm) on center on intermediate framing
15
32
R603.9.2 Determination of minimum length of full- members, the following shall apply:
height sheathing. The minimum length of full-height 1. Multiplying the percentages of full-height sheathing
sheathing on each braced wall line shall be determined by in Table R603.9.2(1) by 0.72 shall be permitted.
multiplying the length of the braced wall line by the per- 2. For bottom track attached to foundations or framing
centage obtained from Table R603.9.2(1) and by the plan below, the bottom track anchor or screw connection
aspect-ratio adjustment factors obtained from Table spacing in Tables R505.3.1(1) and R603.3.1 shall be
R603.9.2(2). The minimum length of full-height sheathing multiplied by two-thirds
shall be not less than 20 percent of the braced wall line
length. R603.9.4 Uplift connection requirements. Uplift con-
nections shall be provided in accordance with this section.
To be considered full-height sheathing, structural
sheathing shall extend from the bottom to the top of the R603.9.4.1 Ultimate design wind speeds greater than
wall without interruption by openings. Only sheathed, full- 130 mph. Where ultimate design wind speeds exceed
height wall sections, uninterrupted by openings, which are 130 miles per hour (58 m/s), Exposure Category C
not less than 48 inches (1219 mm) wide, shall be counted walls shall be provided with direct uplift connections in
toward meeting the minimum percentages in Table accordance with AISI S230, Section E13.3, and AISI
R603.9.2(1). In addition, structural sheathing shall comply S230, Section F8.2, as required for 140 miles per hour
with all of the following requirements: (63 m/s), Exposure Category C.
1. Be installed with the long dimension parallel to the R603.9.4.2 Hold-down anchor. Where the percentage
stud framing and shall cover the full vertical height of of full-height sheathing is adjusted in accordance with
wall from the bottom of the bottom track to the top of Section R603.9.2.2, a hold-down anchor, with a
the top track of each story. Installing the long dimen- strength of 4,300 pounds (19 kN), shall be provided at
sion perpendicular to the stud framing or using each end of each full-height sheathed wall section used
shorter segments shall be permitted provided that the to meet the minimum percent sheathing requirements of
horizontal joint is blocked as described in Item 2. Section R603.9.2. Hold-down anchors shall be attached
to back-to-back studs; structural sheathing panels shall
2. Be blocked where the long dimension is installed have edge fastening to the studs, in accordance with
perpendicular to the stud framing. Blocking shall be Section R603.9.3 and AISI S230, Table E11-1.
not less than 33 mil (0.84 mm) thickness. Each hori-
zontal structural sheathing panel shall be fastened A single hold-down anchor, installed in accordance
with No. 8 screws spaced at 6 inches (152 mm) on with Figure R603.9.4.2, shall be permitted at the cor-
center to the blocking at the joint. ners of buildings.
3. Be applied to each end (corners) of each of the exte- R603.9.5 Structural sheathing for stone and masonry
rior walls with a minimum 48-inch-wide (1219 mm) veneer. Where stone and masonry veneer are installed in
panel. accordance with Section R703.8, the length of full-height
sheathing for exterior and interior wall lines backing or
Exception: Where stone or masonry veneer is installed, perpendicular to and laterally supporting walls with veneer
the required length of full-height sheathing and over- shall comply with this section.
turning anchorage required shall be determined in
accordance with Section R603.9.5.

2018 INTERNATIONAL RESIDENTIAL CODE ® 257
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