Section R702

R702.1 General.¶

Interior coverings or wall finishes shall be installed in accordance with this chapter and Tables R702.1(1), R702.1(2), R702.1(3) and R702.3.5. Interior masonry veneer shall comply with the requirements of

Section R703.7.1 for support and Section R703.7.4 for anchorage, except an airspace is not required. Interior finishes and materials shall conform to the flame spread and smoke-development requirements of Section R302.9.

R702.2 Interior plaster.¶

R702.2.1 Gypsum plaster. Gypsum plaster materials shall conform to ASTM C5, C22, C28, C35, C59, C61, C587, C631, C847, C933, C1032 and C1047, and shall be 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 installed in compliance with ASTM C844. Plaster shall be not less than three coats where applied over metal lath and not less than two coats where applied over other bases permitted by this section, except that veneer plaster shall be applied in one coat not to exceed ³ /16 inch (4.76 mm) thickness, provided the total thickness is in accordance with Table R702.1(1).

TABLE R702.1(1) THICKNESS OF PLASTER

PLASTER BASE	FINISHED THICKNESS OF PLASTER FROM FACE OF LATH, MASONRY, CONCRETE (inches)
PLASTER BASE	Gypsum Plaster	Cement Plaster
Expanded metal lath	5/8, minimuma	5/8, minimuma
Wire lath	5/8, minimuma	3/4, minimum (interior)b
Wire lath	5/8, minimuma	7/8, minimum (exterior)b
Gypsum lathg	1/2, minimum	3/4, minimum (interior)b
Masonry wallsc	1/2, minimum	1/2, minimum
Monolithic concrete wallsc, d	5/8, maximum	7/8, maximum
Monolithic concrete ceilingsc, d	3/8, maximume	1/2, maximum
Gypsum veneer basef, g	1/16, minimum	3/4, minimum (interior)b
Gypsum sheathingg	—	3/4, minimum (interior)b
Gypsum sheathingg	—	7/8, minimum (exterior)b

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 ³ /4 inch minimum. 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.

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WALL COVERING

TABLE R702.1(2) GYPSUM PLASTER PROPORTIONS ^a

NUMBER	COAT	PLASTER BASE OR LATH	MAXIMUM VOLUME AGGREGATE PER 100 POUNDS NEAT PLASTERb (cubic feet)
NUMBER	COAT	PLASTER BASE OR LATH	Damp Loose Sanda	Perlite or Vermiculitec
Two-coat work	Base coat	Gypsum lath	2.5	2
Two-coat work	Base coat	Masonry	3	3
Three-coat work	First coat	Lath	2d	2
Three-coat work	Second coat	Lath	3d	2e
Three-coat work	First and second coats	Masonry	3	3

For SI: 1 inch = 25.4 mm, 1 cubic foot = 0.0283 m ³, 1 pound = 0.454 kg. a. Wood-fibered gypsum plaster shall be mixed in the proportions of 100 pounds of gypsum to not more than 1 cubic foot of sand where applied on masonry or

concrete. b. Where determining the amount of aggregate in set plaster, a tolerance of 10 percent shall be allowed. c. Combinations of sand and lightweight aggregate shall be permitted to be used, provided the volume and weight relationship of the combined aggregate to

gypsum plaster is maintained. d. If used for both first and second coats, the volume of aggregate shall be permitted to be 2.5 cubic feet. e. Where plaster is 1 inch or more in total thickness, the proportions for the second coat may be increased to 3 cubic feet.

		TABLE R702.1(3) CEMENT PLASTER PROPORTIONS, PARTS BY VOLUME
COAT	CEMENT PLASTER TYPE	CEMENTITIOUS MATERIALS	CEMENTITIOUS MATERIALS	CEMENTITIOUS MATERIALS	CEMENTITIOUS MATERIALS	VOLUME OF AGGREGATE PER SUM OF SEPARATE VOLUMES OF CEMENTITIOUS MATERIALSb
COAT	CEMENT PLASTER TYPE	Portland Cement Type I, II or III; Blended Hydraulic Cement Type IP, I (S < 70), IL, or IT (S < 70); or Hydraulic Cement Type GU, HE, MS, HS or MH	Plastic Cement	Masonry Cement Type M, S or N	Lime	Lime
First	Portland or blended	1	—	—	3/4−11/2 a	21/2−4
First	Masonry	—	—	1	—	21/2−4
First	Plastic	—	1	—	—	21/2−4
Second	Portland or blended	1	—	—	3/4−11/2	3−5
Second	Masonry	—	—	1	—	3−5
Second	Plastic	—	1	—	—	3−5
Finish	Portland or blended	1	—	—	11/2−2	11/2−3
Finish	Masonry	—	—	1	—	11/2−3
Finish	Plastic	—	1	—	—	11/2−3

a. Lime by volume of 0 to ³ /4 shall be used where the plaster will be placed over low-absorption surfaces such as dense clay tile or brick. b. The same or greater sand proportion shall be used in the second coat than used in the first coat.

R702.2.2 Cement plaster. Cement plaster materials shall conform to ASTM C91 (Type M, S or N), C150 (Types I, II and III), C595 [Types IP, I (PM), IS and I (SM)], C847, C897, C933, C1032, C1047 and C1328, and shall be installed or applied in compliance with ASTM C926 and C1063. Gypsum lath shall conform to ASTM C1396. Plaster shall be not less than three coats where applied over metal lath and not less than two coats where applied over other bases permitted by this section.

R702.2.2.1 Application. Each coat shall be kept in a moist condition for not less than 24 hours prior to application of the next coat.

Exception: Applications installed in accordance with ASTM C926.

R702.2.2.2 Curing. The finish coat for two-coat cement plaster shall not be applied sooner than 48 hours after application of the first coat. For three-coat cement plaster, the second coat shall not be applied sooner than 24 hours after application of the first coat. The finish coat for three-coat cement plaster shall not be applied sooner than 48 hours after application of the second coat.

R702.2.3 Support. Support spacing for gypsum or metal lath on walls or ceilings shall not exceed 16 inches (406 mm) for ³ /8-inch-thick (9.5 mm) or 24 inches (610 mm) for 1/2-inch-thick (12.7 mm) plain gypsum lath. Gypsum lath shall be installed at right angles to support framing with end joints in adjacent courses staggered by not less than one framing space.

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R702.3 Gypsum board and gypsum panel products.¶

R702.3.1 Materials. Gypsum board and gypsum panel product materials and accessories shall conform to ASTM C22, C475, C514, C1002, C1047, C1177, C1178, C1278, C1396, C1658 or C1766 and shall be installed in accordance with the provisions of this section. Adhesives for the installation of gypsum board and gypsum panel products shall conform to ASTM C557.

R702.3.1.1 Adhesives. Expandable foam adhesives for the installation of gypsum board and gypsum panel products shall conform to ASTM D6464. Other adhesives for the installation of gypsum board and gypsum panel products shall conform to ASTM C557. Supports and fasteners used to attach gypsum board and gypsum panel products shall comply with Table R702.3.5 or other approved method.

R702.3.2 Wood framing. Wood framing supporting gypsum board and gypsum panel products shall be not less than 2 inches (51 mm) nominal thickness in the least dimension except that wood furring strips not less than 1-inch by 2-inch (25 mm by 51 mm) nominal dimension shall be permitted to be used over solid backing or framing spaced not more than 24 inches (610 mm) on center.

R702.3.3 Cold-formed steel framing. Cold-formed steel framing supporting gypsum board and gypsum panel products shall be not less than 1 ¹ /4 inches (32 mm) wide in the least dimension. Nonload-bearing coldformed steel framing shall comply with AISI S220. Load-bearing cold-formed steel framing shall comply with AISI S240.

R702.3.4 Insulating concrete form walls. Foam plastics for insulating concrete form walls constructed in accordance with Sections R404.1.2 and R608 on the interior of habitable spaces shall be protected in accordance with Section R316.4. Use of adhesives in conjunction with mechanical fasteners is permitted. Adhesives used for interior and exterior finishes shall be compatible with the insulating form materials.

R702.3.5 Application. Supports and fasteners used to attach gypsum board and gypsum panel products shall comply with Table R702.3.5. Gypsum sheathing shall be attached to exterior walls in accordance with Table R602.3(1). Gypsum board and gypsum panel products shall be applied at right angles or parallel to framing members. All edges and ends of gypsum board and gypsum panel products shall occur on the framing members, except those edges and ends that are perpendicular to the framing members. Interior gypsum board shall not be installed where it is directly exposed to the weather or to water.

WALL COVERING

R702.3.5.1 Screw fastening. Screws for attaching gypsum board and gypsum panel products to wood framing shall be Type W or Type S in accordance with ASTM C1002 and shall penetrate the wood not less than ⁵ /8 inch (15.9 mm). Gypsum board and gypsum panel products shall be attached to coldformed steel framing with minimum No. 6 screws. Screws for attaching gypsum board and gypsum panel products to cold-formed steel framing less than 0.033 inch (1 mm) thick shall be Type S in accordance with ASTM C1002 or bugle head style in accordance with ASTM C1513 and shall penetrate the steel not less than ³ /8 inch (9.5 mm). Screws for attaching gypsum board and gypsum panel products to cold-formed steel framing 0.033 inch to 0.112 inch (1 mm to 3 mm) thick shall be in accordance with ASTM C954 or bugle head style in accordance with ASTM C1513. Screws for attaching gypsum board and gypsum panel products to structural insulated panels shall penetrate the wood structural panel facing not less than ⁷ /16 inch (11.1 mm).

R702.3.6 Horizontal gypsum board diaphragm ceil- ings. Gypsum board and gypsum panel products shall be permitted on wood joists to create a horizontal diaphragm in accordance with Table R702.3.6. Gypsum board and gypsum panel products shall be installed perpendicular to ceiling framing members. End joints of adjacent courses of board and panels shall not occur on the same joist. The maximum allowable diaphragm proportions shall be 1 ¹ /2:1 between shear resisting elements. Rotation or cantilever conditions shall not be permitted. Gypsum board or gypsum panel products shall not be used in diaphragm ceilings to resist lateral forces imposed by masonry or concrete construction. Perimeter edges shall be blocked using wood members not less than 2-inch by 6-inch (51 mm by 152 mm) nominal dimension. Blocking material shall be installed flat over the top plate of the wall to provide a nailing surface not less than 2 inches (51 mm) in width for the attachment of the gypsum board or gypsum panel product.

R702.3.7 Water-resistant gypsum backing board. Gypsum board used as the base or backer for adhesive application of ceramic tile or other required nonabsorbent finish material shall conform to ASTM C1178, C1278 or C1396. Use of water-resistant gypsum backing board shall be permitted on ceilings. Water-resistant gypsum board shall not be installed over a Class I or II vapor retarder in a shower or tub compartment. Cut or exposed edges, including those at wall intersections, shall be sealed as recommended by the manufacturer.

R702.3.7.1 Limitations. Water-resistant gypsum backing board shall not be used where there will be direct exposure to water, or in areas subject to continuous high humidity.

WALL COVERING

TABLE R702.3.5 MINIMUM THICKNESS AND APPLICATION OF GYPSUM BOARD AND GYPSUM PANEL PRODUCTS

THICKNESS OF GYPSUM BOARD OR GYPSUM PANEL PRODUCTS (inches)	APPLICATION	ORIENTATION OF GYPSUM BOARD OR GYPSUM PANEL PRODUCTS TO FRAMING	MAXIMUM SPACING OF FRAMING MEMBERS (inches o.c.)	MAXIMUM SPACING OF FASTENERS (inches)		SIZE OF NAILS FOR APPLICATION TO WOOD FRAMINGc
THICKNESS OF GYPSUM BOARD OR GYPSUM PANEL PRODUCTS (inches)	APPLICATION	ORIENTATION OF GYPSUM BOARD OR GYPSUM PANEL PRODUCTS TO FRAMING	MAXIMUM SPACING OF FRAMING MEMBERS (inches o.c.)	Nailsa	Screwsb	Screwsb
Application without adhesive	Application without adhesive	Application without adhesive	Application without adhesive	Application without adhesive	Application without adhesive	Application without adhesive
3/8	Ceilingd	Perpendicular	16	7	12	13 gage, 11/4″ long,19/64″ head; 0.098″ diameter, 11/4″ long, ring shank; or 4d cooler nail, 0.080″ diameter, 13/8″ long,7/32″ head.
3/8	Wall	Either direction	16	8	16	16
1/2	Ceiling	Either direction	16	7	12	13 gage, 13/8″ long,19/64″ head; 0.098″ diameter, 11/4″ long, ring shank; 5d cooler nail, 0.086″ diameter, 15/8″ long,15/64″ head; or gypsum board nail, 0.086″ diameter, 15/8″ long,9/32″ head.
1/2	Ceilingd	Perpendicular	24	7	12	12
1/2	Wall	Either direction	24	8	12	12
1/2	Wall	Either direction	16	8	16	16
5/8	Ceiling	Either direction	16	7	12	13 gage, 15/8″ long,19/64″ head; 0.098″ diameter, 13/8″ long, ring shank; 6d cooler nail, 0.092″ diameter, 17/8″ long,1/4″ head; or gypsum board nail, 0.0915″ diameter, 17/8″ long,19/64″ head.
5/8	Ceiling	Perpendicular	24	7	12	12
5/8	Type X at garage ceiling beneath habit- able rooms	Perpendicular	24	6	6	17/8″ long 0.099″ diameter galvanized nails or equivalent drywall screws. Screws shall comply with Section R702.3.5.1.
5/8	Wall	Either direction	24	8	12	13 gage, 15/8″ long,19/64″ head; 0.098″ diameter, 13/8″ long, ring shank; 6d cooler nail, 0.092″ diameter, 17/8″ long,1/4″ head; or gypsum board nail, 0.0915″ diameter, 17/8″ long,19/64″ head.
5/8	Wall	Either direction	16	8	16	16
Application with adhesive	Application with adhesive	Application with adhesive	Application with adhesive	Application with adhesive	Application with adhesive	Application with adhesive
3/8	Ceilingd	Perpendicular	16	16	16	Same as above for3/8″ gypsum board and gyp- sum panel products.
3/8	Wall	Either direction	16	16	24	24
1/2 or5/8	Ceiling	Either direction	16	16	16	Same as above for1/2″ and5/8″ gypsum board and gypsum panel products, respectively.
1/2 or5/8	Ceilingd	Perpendicular	24	12	16	16
1/2 or5/8	Wall	Either direction	24	16	24	24
Two3/8 layers	Ceiling	Perpendicular	16	16	16	Base ply nailed as above for1/2″ gypsum board and gypsum panel products; face ply installed with adhesive.
Two3/8 layers	Wall	Either direction	24	24	24	24

For SI: 1 inch = 25.4 mm. a. For application without adhesive, a pair of nails spaced not less than 2 inches apart or more than 2 ¹ /2 inches apart shall be permitted to be used with the pair of

nails spaced 12 inches on center. b. Screws shall be in accordance with Section R702.3.5.1. Screws for attaching gypsum board or gypsum panel products to structural insulated panels shall

penetrate the wood structural panel facing not less than ⁷ /16 inch. c. Where cold-formed steel framing is used with a clinching design to receive nails by two edges of metal, the nails shall be not less than ⁵ /8 inch longer than the

gypsum board or gypsum panel product thickness and shall have ringed shanks. Where the cold-formed steel framing has a nailing groove formed to receive the nails, the nails shall have barbed shanks or be 0.086-inch diameter, 1 ⁵ /8 inches long, ¹⁵ /64-inch head for ¹ /2-inch gypsum board or gypsum panel product; and 0.099-inch diameter, 1 ⁷ /8 inches long, ¹⁵ /64-inch head for ⁵ /8-inch gypsum board or gypsum panel product. d. Three-eighths-inch-thick single-ply gypsum board or gypsum panel product shall not be used on a ceiling where a water-based textured finish is to be applied,

or where it will be required to support insulation above a ceiling. On ceiling applications to receive a water-based texture material, either hand or spray applied, the gypsum board or gypsum panel product shall be applied perpendicular to framing. Where applying a water-based texture material, the minimum gypsum board thickness shall be increased from ³ /8 inch to ¹ /2 inch for 16-inch on center framing, and from ¹ /2 inch to ⁵ /8 inch for 24-inch on center framing or 1/2-inch sag-resistant gypsum ceiling board shall be used.

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WALL COVERING

TABLE R702.3.6 SHEAR CAPACITY FOR HORIZONTAL WOOD-FRAMED GYPSUM BOARD DIAPHRAGM CEILING ASSEMBLIES

MATERIAL	THICKNESS OF MATERIAL (min.) (inch)	SPACING OF FRAMING MEMBERS (max.) (inch)	SHEAR VALUEa, b (plf of ceiling)	MINIMUM FASTENER SIZEc, d
Gypsum board or gyp- sum panel product	1/2	16 o.c.	90	5d cooler or wallboard nail; 15/8-inch long; 0.086-inch shank; 15/64-inch head
Gypsum board or gyp- sum panel product	1/2	24 o.c.	70	5d cooler or wallboard nail; 15/8-inch long; 0.086-inch shank; 15/64-inch head

For SI: 1 inch = 25.4 mm, 1 pound per linear foot = 1.488 kg/m. a. Values are not cumulative with other horizontal diaphragm values and are for short-term loading caused by wind or seismic loading. Values shall be reduced

25 percent for normal loading. b. Values shall be reduced 50 percent in Seismic Design Categories D0, D1, D2 and E. c. 1 ¹ /4-inch, No. 6 Type S or W screws shall be permitted to be substituted for the listed nails. d. Fasteners shall be spaced not more than 7 inches on center at all supports, including perimeter blocking, and not less than ³ /8 inch from the edges and ends of

the gypsum board.

R702.4 Ceramic tile.¶

R702.4.1 General. Ceramic tile surfaces shall be installed in accordance with ANSI A108.1, A108.4, A108.5, A108.6, A108.11, A118.1, A118.3, A136.1 and A137.1.

R702.4.2 Backer boards. Materials used as backers for wall tile in tub and shower areas and wall panels in shower areas shall be of materials listed in Table R702.4.2, and installed in accordance with the manufacturer’s recommendations.

TABLE R702.4.2 BACKER BOARD MATERIALS

MATERIAL	STANDARD
Glass mat gypsum backing panel	ASTM C1178
Fiber-reinforced gypsum panels	ASTM C1278
Nonasbestos fiber-cement backer board	ASTM C1288 or ISO 8336, Category C
Nonasbestos fiber mat-reinforced cementitious backer units	ASTM C1325

R702.5 Other finishes.¶

Wood veneer paneling and hardboard paneling shall be placed on wood or cold-formed steel framing spaced not more than 16 inches (406 mm) on center. Wood veneer and hard board paneling less than ¹ /4-inch (6 mm) nominal thickness shall not have less than a ³ /8-inch (10 mm) gypsum board or gypsum panel product backer. Wood veneer paneling not less than ¹ /4-inch (6 mm) nominal thickness shall conform to ANSI/HPVA HP-1. Hardboard paneling shall conform to CPA/ANSI A135.5.

R702.6 Wood shakes and shingles.¶

Wood shakes and shingles shall conform to CSSB Grading Rules for Wood Shakes and Shingles and shall be permitted to be installed directly to the studs with maximum 24 inches (610 mm) on-center spacing.

R702.6.1 Attachment. Nails, staples or glue are permitted for attaching shakes or shingles to the wall, and attachment of the shakes or shingles directly to the surface shall be permitted provided the fasteners are appropriate for the

type of wall surface material. Where nails or staples are used, two fasteners shall be provided and shall be placed so that they are covered by the course above.

R702.6.2 Furring strips. Where furring strips are used, they shall be 1 inch by 2 inches or 1 inch by 3 inches (25 mm by 51 mm or 25 mm by 76 mm), spaced a distance on center equal to the desired exposure, and shall be attached to the wall by nailing through other wall material into the studs.

R702.7 Vapor retarders.¶

Vapor retarder materials shall be classified in accordance with Table R702.7(1). A vapor retarder shall be provided on the interior side of frame walls of the class indicated in Table R702.7(2), including compliance with Table R702.7(3) or R702.7(4) where applicable. An approved design using accepted engineering practice for hygrothermal analysis shall be permitted as an alternative. The climate zone shall be determined in accordance with Section N1101.7.

Exceptions:

Basement walls.
Below-grade portion of any wall.
Construction where accumulation, condensation or freezing of moisture will not damage the materials.
A vapor retarder shall not be required in Climate Zones 1, 2 and 3.

R702.7.1 Spray foam plastic insulation for moisture control with Class II and III vapor retarders. For purposes of compliance with Tables R702.7(3) and R702.7(4), spray foam with a maximum permeance of 1.5 perms at the installed thickness applied to the interior side of wood structural panels, fiberboard, insulating sheathing or gypsum shall be deemed to meet the continuous insulation moisture control requirement in accordance with one of the following conditions:

The spray foam R -value is equal to or greater than the specified continuous insulation R -value.

flashed in accordance with Section R703.4 or R703.8.

Compliance with the requirements for a means of drainage, and the requirements of Sections R703.2 and R703.4, shall not be required for an exterior wall envelope that has been demonstrated to resist wind-driven rain through testing of the exterior wall envelope, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E331 under the following conditions:

2.1. Exterior wall envelope test assemblies shall include at least one opening, one control joint, one wall/eave interface and one wall sill. All tested openings and penetrations shall be representative of the intended end-use configuration.

2.2. Exterior wall envelope test assemblies shall be at least 4 feet by 8 feet (1219 mm by 2438 mm) in size.

2.3. Exterior wall assemblies shall be tested at a minimum differential pressure of 6.24 pounds per square foot (299 Pa).

2.4. Exterior wall envelope assemblies shall be subjected to the minimum test exposure for a minimum of 2 hours.

The exterior wall envelope design shall be considered to resist wind-driven rain where the results of testing indicate that water did not penetrate control joints in the exterior wall envelope, joints at the perimeter of openings penetration or intersections of terminations with dissimilar materials.

WALL COVERING

The combined R -value of the spray foam and continuous insulation is equal to or greater than the specified continuous insulation R -value.

R702.7.2 California Energy Code and International Energy Conservation Code Climate Zones. The IECC climate zones used by this section differ from those used by the California Energy Code to determine applicability of energy efficiency measures. Comparison of IECC and California Energy Code climate zones is shown in Table R702.7(5).