Page 384 - 2018_IRC

CHAPTER 7

WALL COVERING

User note:
About this chapter: Chapter 7 establishes the various types of materials, materials standards and methods of application permitted as inte-
rior and exterior wall coverings. Interior coverings include interior plaster, gypsum board, ceramic tile, wood veneer paneling, hardboard pan-
eling, wood shakes and wood shingles. Exterior wall coverings regulated by this section include aluminum, stone and masonry veneer, wood,
hardboard, particleboard, wood structural panel siding, wood shakes and shingles, exterior plaster, steel, vinyl, fiber cement and exterior insu-
lation finish systems. This chapter also contains requirements for the use of vapor retarders for moisture control in walls; wind resistance and
water-resistive barriers for exterior wall coverings; and the water-resistive barrier required beneath exterior materials.

SECTION R701 Section R703.7.1 for support and Section R703.7.4 for
GENERAL anchorage, except an airspace is not required. Interior finishes
R701.1 Application. The provisions of this chapter shall and materials shall conform to the flame spread and smoke-
control the design and construction of the interior and exte- development requirements of Section R302.9.
rior wall covering for buildings. R702.2 Interior plaster.
R701.2 Installation. Products sensitive to adverse weather R702.2.1 Gypsum plaster. Gypsum plaster materials
shall not be installed until adequate weather protection for the shall conform to ASTM C5, C22, C28, C35, C59, C61,
installation is provided. Exterior sheathing shall be dry before C587, C631, C847, C933, C1032 and C1047, and shall be
applying exterior cover. installed or applied in compliance with ASTM C841,
C842 and C843. Gypsum lath or gypsum base for veneer
plaster shall conform to ASTM C1396 and shall be
SECTION R702 installed in compliance with ASTM C844. Plaster shall be
INTERIOR COVERING not less than three coats where applied over metal lath and
R702.1 General. Interior coverings or wall finishes shall be not less than two coats where applied over other bases per-
installed in accordance with this chapter and Table R702.1(1), mitted by this section, except that veneer plaster shall be
3
Table R702.1(2), Table R702.1(3) and Table R702.3.5. Inte- applied in one coat not to exceed / inch (4.76 mm) thick-
16
rior masonry veneer shall comply with the requirements of ness, provided the total thickness is in accordance with
Table R702.1(1).
TABLE R702.1(1)
THICKNESS OF PLASTER
FINISHED THICKNESS OF PLASTER FROM FACE OF LATH, MASONRY, CONCRETE (inches)
PLASTER BASE
Gypsum Plaster Cement Plaster
Expanded metal lath 5 / , minimum a 5 / , minimum a
8
8
3 / , minimum (interior) b
4
Wire lath 5 / , minimum a 7 / , minimum (exterior) b
8
8
g
Gypsum lath 1 / , minimum 3 / , minimum (interior) b
4
2
c
Masonry walls 1 / , minimum 1 / , minimum
2
2
c, d
Monolithic concrete walls 5 / , maximum 7 / , maximum
8
8
c, d
Monolithic concrete ceilings 3 / , maximum e 1 / , maximum
8
2
f, g
Gypsum veneer base 1 / , minimum 3 / , minimum (interior) b
16
4
3 / , minimum (interior) b
Gypsum sheathing g — 7 / , minimum (exterior) b
4
8
For SI: 1 inch = 25.4 mm.
a. Where measured from back plane of expanded metal lath, exclusive of ribs, or self-furring lath, plaster thickness shall be / inch minimum.
3
4
b. Where measured from face of support or backing.
c. Because masonry and concrete surfaces vary in plane, thickness of plaster need not be uniform.
d. Where applied over a liquid bonding agent, finish coat shall be permitted to be applied directly to concrete surface.
e. Approved acoustical plaster shall be permitted to be applied directly to concrete or over base coat plaster, beyond the maximum plaster thickness shown.
f. Attachment shall be in accordance with Table R702.3.5.
g. Where gypsum board is used as a base for cement plaster, a water-resistive barrier complying with Section R703.2 shall be provided.
2018 INTERNATIONAL RESIDENTIAL CODE ® 359
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