Page 292 - 2018_IRC

WALL CONSTRUCTION

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R606.6.3.1 Joist bearing. Joists shall have a bearing of instructions, / -inch (13 mm) bolts spaced not more
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not less than 1 / inches (38 mm), except as provided in than 6 feet (1829 mm) on center, or other approved
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Section R606.6.3, and shall be supported in accordance anchors. Anchors shall be embedded not less than 16
with Figure R606.11(1). inches (406 mm) into the masonry, or be hooked or
R606.6.4 Lateral support. Masonry walls shall be later- welded to bond beam reinforcement placed not less
ally supported in either the horizontal or the vertical direc- than 6 inches (152 mm) from the top of the wall.
tion. The maximum spacing between lateral supports shall R606.6.4.2.2 Floor diaphragms. Masonry walls
not exceed the distances in Table R606.6.4. Lateral sup- shall be anchored to floor diaphragm framing by
port shall be provided by cross walls, pilasters, buttresses metal strap anchors spaced in accordance with the
or structural frame members where the limiting distance is manufacturer’s instructions, / -inch-diameter (13
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taken horizontally, or by floors or roofs where the limiting mm) bolts spaced at intervals not to exceed 6 feet
distance is taken vertically. (1829 mm) and installed as shown in Figure
TABLE R606.6.4 R606.11(1), or by other approved methods.
SPACING OF LATERAL SUPPORT FOR MASONRY WALLS R606.7 Piers. The unsupported height of masonry piers shall
MAXIMUM WALL LENGTH TO THICKNESS
CONSTRUCTION not exceed 10 times their least dimension. Where structural
OR WALL HEIGHT TO THICKNESS a, b
Bearing walls: clay tile or hollow concrete masonry units are used for isolated
Solid or solid grouted 20 piers to support beams and girders, the cellular spaces shall be
All other 18 filled solidly with grout or Type M or S mortar, except that
Nonbearing walls: unfilled hollow piers shall be permitted to be used if their
Exterior 18 unsupported height is not more than four times their least
Interior 36 dimension. Where hollow masonry units are solidly filled with
For SI: 1 foot = 304.8 mm. grout or Type M, S or N mortar, the allowable compressive
a. Except for cavity walls and cantilevered walls, the thickness of a wall shall stress shall be permitted to be increased as provided in Table
be its nominal thickness measured perpendicular to the face of the wall. For R606.9.
cavity walls, the thickness shall be determined as the sum of the nominal
thicknesses of the individual wythes. For cantilever walls, except for R606.7.1 Pier cap. Hollow piers shall be capped with 4
parapets, the ratio of height to nominal thickness shall not exceed 6 for solid inches (102 mm) of solid masonry or concrete, a masonry
masonry, or 4 for hollow masonry. For parapets, see Section R606.4.4. cap block, or shall have cavities of the top course filled
b. An additional unsupported height of 6 feet is permitted for gable end walls. with concrete or grout.
R606.6.4.1 Horizontal lateral support. Lateral sup-
port in the horizontal direction provided by intersecting R606.8 Chases. Chases and recesses in masonry walls shall
masonry walls shall be provided by one of the methods not be deeper than one-third the wall thickness. The maximum
in Section R606.6.4.1.1 or R606.6.4.1.2. length of a horizontal chase or horizontal projection shall not
exceed 4 feet (1219 mm) and shall have not less than 8 inches
R606.6.4.1.1 Bonding pattern. Fifty percent of the (203 mm) of masonry in back of the chases and recesses and
units at the intersection shall be laid in an overlap- between adjacent chases or recesses and the jambs of openings.
ping masonry bonding pattern, with alternate units Chases and recesses in masonry walls shall be designed and
having a bearing of not less than 3 inches (76 mm) constructed so as not to reduce the required strength or required
on the unit below. fire resistance of the wall and shall not be permitted within the
R606.6.4.1.2 Metal reinforcement. Interior non- required area of a pier. Masonry directly above chases or
load-bearing walls shall be anchored at their intersec- recesses wider than 12 inches (305 mm) shall be supported on
tions, at vertical intervals of not more than 16 inches noncombustible lintels.
(406 mm) with joint reinforcement of not less than 9 R606.9 Allowable stresses. Allowable compressive stresses
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gage [0.148 inch (4 mm)], or / -inch (6 mm) galva- in masonry shall not exceed the values prescribed in Table
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nized mesh hardware cloth. Intersecting masonry R606.9. In determining the stresses in masonry, the effects of
walls, other than interior nonload-bearing walls, shall all loads and conditions of loading and the influence of all
be anchored at vertical intervals of not more than 8 forces affecting the design and strength of the several parts
inches (203 mm) with joint reinforcement of not less shall be taken into account.
than 9 gage (4 mm) and shall extend not less than 30
inches (762 mm) in each direction at the intersection. R606.9.1 Combined units. In walls or other structural
Other metal ties, joint reinforcement or anchors, if members composed of different kinds or grades of units,
used, shall be spaced to provide equivalent area of materials or mortars, the maximum stress shall not exceed
anchorage to that required by this section. the allowable stress for the weakest of the combination of
units, materials and mortars of which the member is com-
R606.6.4.2 Vertical lateral support. Vertical lateral posed. The net thickness of any facing unit that is used to
support of masonry walls in Seismic Design Category resist stress shall be not less than 1 / inches (38 mm).
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A, B or C shall be provided in accordance with one of 2
the methods in Section R606.6.4.2.1 or R606.6.4.2.2. R606.10 Lintels. Masonry over openings shall be supported
by steel lintels, reinforced concrete or masonry lintels or
R606.6.4.2.1 Roof structures. Masonry walls shall masonry arches, designed to support load imposed.
be anchored to roof structures with metal strap
anchors spaced in accordance with the manufacturer’s

2018 INTERNATIONAL RESIDENTIAL CODE ® 267
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