Page 80 - 2018_IRC

BUILDING PLANNING

from the foundation to the uppermost story in (2438 mm) in width in the wall below pro-
which they are required. vided that the opening includes a header in
Exception: For wood light-frame construc- accordance with all of the following:
tion, floors with cantilevers or setbacks not 1. The building width, loading condition
exceeding four times the nominal depth of the and framing member species limitations
wood floor joists are permitted to support of Table R602.7(1) shall apply.
braced wall panels that are out of plane with 2. The header is composed of:
braced wall panels below provided that all of 2.1. Not less than one 2 × 12 or two
the following are satisfied:
2 × 10 for an opening not more
1. Floor joists are nominal 2 inches by 10 than 4 feet (1219 mm) wide.
inches (51 mm by 254 mm) or larger 2.2. Not less than two 2 × 12 or three
and spaced not more than 16 inches (406 2 × 10 for an opening not more
mm) on center.
than 6 feet (1829 mm) in width.
2. The ratio of the back span to the 2.3. Not less than three 2 × 12 or four
cantilever is not less than 2 to 1. 2 × 10 for an opening not more
3. Floor joists at ends of braced wall than 8 feet (2438 mm) in width.
panels are doubled. 3. The entire length of the braced wall
4. Fo wood-frame construction, a panel does not occur over an opening in
continuous rim joist is connected to ends the wall below.
of cantilever joists. Where spliced, the 4. Floor and roof opening. Conditions where an
rim joists shall be spliced using a opening in a floor or roof exceeds the lesser of 12
galvanized metal tie not less than 0.058 feet (3658 mm) or 50 percent of the least floor or
1
inch (1.5 mm) (16 gage) and 1 / inches roof dimension.
2
(38 mm) wide fastened with six 16d
nails on each side of the splice; or a 5. Floor level offset. Conditions where portions of
block of the same size as the rim joist a floor level are vertically offset.
and of sufficient length to fit securely Exceptions:
between the joist space at which the 1. Frami supported directl by
splice occurs, fastened with eight 16d continuous foundations at the perimeter
nails on each side of the splice. of the building.
5. Gravity loads carried at the end of 2. For wood light-frame construction,
cantilevered joists are limited to uniform floors shall be permitted to be vertically
wall and roof loads and the reactions offset where the floor framing is lapped
from headers having a span of 8 feet or tied together as required by Section
(2438 mm) or less. R502.6.1.
2. Lateral support of roofs and floors. Conditions 6. Perpendicular shear wall and wall bracing.
where a section of floor or roof is not laterally Conditions where shear walls and braced wall
supported by shear walls or braced wall lines on lines do not occur in two perpendicular directions.
all edges. 7. Wall bracing in stories containing masonry or
Exception: Portions of floors that do not sup- concrete construction. Conditions where stories
port shear walls, braced wall panels above, or above grade plane are partially or completely
roofs shall be permitted to extend not more braced by wood wall framing in accordance with
than 6 feet (1829 mm) beyond a shear wall or Section R602 or cold-formed steel wall framing
braced wall line. in accordance with Section R603 include
3. Shear wall or braced wall offsets in plane. masonry or concrete construction. Where this
Conditions where the end of a braced wall panel irregularity applies, the entire story shall be
occurs over an opening in the wall below and designed in accordance with accepted engineer-
extends more than 1 foot (305 mm) horizontally ing practice.
past the edge of the opening. This provision is Exceptions: Fireplaces chimneys and
applicable to shear walls and braced wall panels masonry veneer in accordance with this code.
offset in plane and to braced wall panels offset R301.2.2.7 Height limitations. Wood-framed build-
out of plane in accordance with the exception to
Item 1. ings shall be limited to three stories above grade plane
or the limits given in Table R602.10.3(3). Cold-formed
Exception: For wood light-frame wall con- steel-framed buildings shall be limited to less than or
struction, one end of a braced wall panel shall equal to three stories above grade plane in accordance
be permitted to extend more than 1 foot (305 with AISI S230. Mezzanines as defined in Section
mm) over an opening not more than 8 feet R202 that comply with Section R325 shall not be con-

2018 INTERNATIONAL RESIDENTIAL CODE ® 55
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