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 interior and exterior wall coverings. Interior coverings include interior plaster, gypsum board, ceramic tile, wood veneer paneling, hardboard paneling, 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 insulation 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 General

R701.1 Application

The provisions of this chapter shall control the design and construction of the interior and exterior wall covering for buildings.

R701.2 Installation

Products sensitive to adverse weather shall not be installed until adequate weather protection for the installation is provided. Exterior sheathing shall be dry before applying exterior cover.

Section R702 Interior Covering

R702.1 General

Interior coverings or wall finishes shall be installed in accordance with this chapter and Table R702.1(1), Table R702.1(2), Table R702.1(3) and Table 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.
TABLE R702.1(1)
THICKNESS OF PLASTER
PLASTER BASE FINISHED THICKNESS OF PLASTER FROM FACE OF LATH, MASONRY, CONCRETE (inches)
Gypsum Plaster Cement Plaster
Expanded metal lath 5/8, minimuma 5/8, minimuma
Wire lath 5/8, minimuma 3/4, minimum (interior)b
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
7/8, minimum (exterior)b
For SI: 1 inch = 25.4 mm.
  1. Where measured from back plane of expanded metal lath, exclusive of ribs, or self-furring lath, plaster thickness shall be 3/4 inch minimum.
  2. Where measured from face of support or backing.
  3. Because masonry and concrete surfaces vary in plane, thickness of plaster need not be uniform.
  4. Where applied over a liquid bonding agent, finish coat shall be permitted to be applied directly to concrete surface.
  5. Approved acoustical plaster shall be permitted to be applied directly to concrete or over base coat plaster, beyond the maximum plaster thickness shown.
  6. Attachment shall be in accordance with Table R702.3.5.
  7. Where gypsum board is used as a base for cement plaster, a water-resistive barrier complying with Section R703.2 shall be provided.
TABLE R702.1(2)
GYPSUM PLASTER PROPORTIONSa
NUMBER COAT PLASTER BASE OR LATH MAXIMUM VOLUME AGGREGATE PER 100 POUNDS NEAT PLASTERb
(cubic feet)
Damp Loose Sanda Perlite or Vermiculitec
Two-coat work Base coat Gypsum lath 2.5 2
Base coat Masonry 3 3
Three-coat work First coat Lath 2d 2
Second coat Lath 3d 2e
First and second coats Masonry 3 3
For SI: 1 inch = 25.4 mm, 1 cubic foot = 0.0283 m3, 1 pound = 0.454 kg.
  1. 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.
  2. Where determining the amount of aggregate in set plaster, a tolerance of 10 percent shall be allowed.
  3. 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.
  4. If used for both first and second coats, the volume of aggregate shall be permitted to be 2.5 cubic feet.
  5. 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 VOLUME OF
AGGREGATE PER
SUM OF SEPARATE
VOLUMES OF
CEMENTITIOUS
MATERIALSb
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
First Portland or blended 1 — — 3/4 - 11/2a 21/2 - 4
Masonry — 1 — 21/2 - 4
Plastic — 1 — — 21/2 - 4
Second Portland or blended 1 — — 3/4 - 11/2 3 - 5
Masonry — 1 — 3 - 5
Plastic — 1 — — 3 - 5
Finish Portland or blended 1 — — 11/2 - 2 11/2 - 3
Masonry — — 1 — 11/2 - 3
Plastic — 1 — 11/2 - 3
For SI: 1 inch = 25.4 mm, 1 pound = 0.454 kg.
  1. 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.
  2. The same or greater sand proportion shall be used in the second coat than used in the first coat.

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).

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.

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 11/4 inches (32 mm) wide in the least dimension. Nonload-bearing cold-formed 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.
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
Nailsa Screwsb
Application without adhesive
3/8 Ceilingd Perpendicular 16 7 12 13 gage, 11/4" long, 19/64" head; 0.098" diameter, 11/4" long, annular-ringed; or 4d cooler nail, 0.080" diameter, 13/8" long, 7/32" head.
Wall Either direction 16 8 16
1/2 Ceiling Either direction 16 7 12 13 gage, 13/8" long, 19/64" head; 0.098" diameter, 11/4" long, annular-ringed; 5d cooler nail, 0.086" diameter, 15/8" long, 15/64" head; or gypsum board nail, 0.086" diameter, 1 5/8" long, 9/32" head.
Ceilingd Perpendicular 24 7 12
Wall Either direction 24 8 12
Wall Either direction 16 8 16
5/8 Ceiling Either direction 16 7 12 13 gage, 15/8" long, 19/64" head; 0.098" diameter, 13/8" long, annular-ringed; 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.
Ceiling Perpendicular 24 7 12
Type X at
garage ceiling
beneath
habitable rooms
 Perpendicular 24 6 6 17/8" long 6d coated nails or equivalent drywall screws. Screws shall comply with Section R702.3.5.1
Wall Either direction 24 8 12 13 gage, 15/8" long, 19/64" head; 0.098" diameter, 13/8" long, annular-ringed; 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.
Wall Either direction 16 8 16
Application with adhesive
3/8 Ceilingd Perpendicular 16 16 16 Same as above for 3/8" gypsum board and gypsum panel products.
Wall Either direction 16 16 24
1/2 or 5/8 Ceiling Either direction 16 16 16 Same as above for 1/2" and 5/8" gypsum board and gypsum panel products, respectively.
Ceilingd Perpendicular 24 12 16
Wall Either direction 24 16 24
Two
3/8 layers
 Ceiling Perpendicular 16 16 16 Base ply nailed as above for 1/2" gypsum board and gypsum panel products; face ply installed with adhesive.
Wall Either direction 24 24 24
For SI: 1 inch = 25.4 mm.
  1. For application without adhesive, a pair of nails spaced not less than 2 inches apart or more than 21/2 inches apart shall be permitted to be used with the pair of nails spaced 12 inches on center.
  2. 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.
  3. 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 5d, 131/2 gage, 15/8 inches long, 15/64-inch head for 1/2-inch gypsum board or gypsum panel product; and 6d, 13 gage, 17/8 inches long, 15/64-inch head for 5/8-inch gypsum board or gypsum panel product.
  4. 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.

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 cold-formed 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 Ceilings

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 11/2:1 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.
TABLE R702.3.6
SHEAR CAPACITY FOR HORIZONTAL WOOD-FRAMED GYPSUM BOARD DIAPHRAGM CEILING ASSEMBLIES
MATERIALTHICKNESS OF
MATERIAL (min.) (inch)
SPACING OF FRAMING
MEMBERS (max.) (inch)
SHEAR VALUEa, b
(plf of ceiling)
MINIMUM
FASTENER SIZEc, d
Gypsum board1/216 o.c.905d cooler or wallboard nail;
15/8-inch long; 0.086-inch shank;
15/64-inch head
Gypsum board1/224 o.c.705d 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.
  1. 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.
  2. Values shall be reduced 50 percent in Seismic Design Categories D0, D1, D2 and E.
  3. 11/4-inch, No. 6 Type S or W screws shall be permitted to be substituted for the listed nails.
  4. 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.

R702.3.7 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.

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
MATERIALSTANDARD
Glass mat gypsum backing panelASTM C1178
Fiber-reinforced gypsum panelsASTM 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

Class I or II vapor retarders are required on the interior side of frame walls in Climate Zones 5, 6, 7, 8 and Marine 4.
Exceptions:
  1. Basement walls.
  2. Below-grade portion of any wall.
  3. Construction where moisture or its freezing will not damage the materials.

R702.7.1 Class III Vapor Retarders

Class III vapor retarders shall be permitted where any one of the conditions in Table R702.7.1 is met.
TABLE R702.7.1
CLASS III VAPOR RETARDERS
CLIMATE
ZONE
CLASS III VAPOR RETARDERS PERMITTED FOR:a
Marine 4Vented cladding over wood structural panels.
Vented cladding over fiberboard.
Vented cladding over gypsum.
Continuous insulation with R-value ≥ 2.5 over 2 × 4 wall.
Continuous insulation with R-value ≥ 3.75 over 2 × 6 wall.
5Vented cladding over wood structural panels.
Vented cladding over fiberboard.
Vented cladding over gypsum.
Continuous insulation with R-value ≥ 5 over 2 × 4 wall.
Continuous insulation with R-value ≥ 7.5 over 2 × 6 wall.
6Vented cladding over fiberboard.
Vented cladding over gypsum.
Continuous insulation with R-value ≥ 7.5 over 2 × 4 wall.
Continuous insulation with R-value ≥ 11.25 over 2 × 6 wall.
7 and 8Continuous insulation with R-value ≥ 10 over 2 × 4 wall.
Continuous insulation with R-value ≥ 15 over 2 × 6 wall.
For SI: 1 pound per cubic foot = 16 kg/m3.
  1. Spray foam with a maximum permeance of 1.5 perms at the installed thickness, applied to the interior cavity side of wood structural panels, fiberboard, insulating sheathing or gypsum is deemed to meet the continuous insulation requirement where the spray foam R-value meets or exceeds the specified continuous insulation R-value.

R702.7.2 Material Vapor Retarder Class

The vapor retarder class shall be based on the manufacturer's certified testing or a tested assembly.
The following shall be deemed to meet the class specified:
  1. Class I: Sheet polyethylene, unperforated aluminum foil.
  2. Class II: Kraft-faced fiberglass batts.
  3. Class III: Latex or enamel paint.

R702.7.3 Minimum Clear Airspaces and Vented Openings for Vented Cladding

For the purposes of this section, vented cladding shall include the following minimum clear airspaces. Other openings with the equivalent vent area shall be permitted.
  1. Vinyl polypropylene or horizontal aluminum siding applied over a weather-resistive barrier as specified in Table R703.3(1).
  2. Brick veneer with a clear airspace as specified in Table R703.8.4.
  3. Other approved vented claddings.

Section R703 Exterior Covering

R703.1 General

Exterior walls shall provide the building with a weather-resistant exterior wall envelope. The exterior wall envelope shall include flashing as described in Section R703.4.
Exception: Log walls designed and constructed in accordance with the provisions of ICC 400.

R703.1.1 Water Resistance

The exterior wall envelope shall be designed and constructed in a manner that prevents the accumulation of water within the wall assembly by providing a water-resistant barrier behind the exterior cladding as required by Section R703.2 and a means of draining to the exterior water that penetrates the exterior cladding.
Exceptions:
  1. A weather-resistant exterior wall envelope shall not be required over concrete or masonry walls designed in accordance with Chapter 6 and flashed in accordance with Section R703.4 or R703.8.
  2. 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:
    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. Exterior wall envelope test assemblies shall be at least 4 feet by 8 feet (1219 mm by 2438 mm) in size.
    3. Exterior wall assemblies shall be tested at a minimum differential pressure of 6.24 pounds per square foot (299 Pa).
    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.

R703.1.2 Wind Resistance

Wall coverings, backing materials and their attachments shall be capable of resisting wind loads in accordance with Tables R301.2(2) and R301.2(3). Wind-pressure resistance of the siding, soffit and backing materials shall be determined by ASTM E330 or other applicable standard test methods. Where wind-pressure resistance is determined by design analysis, data from approved design standards and analysis conforming to generally accepted engineering practice shall be used to evaluate the siding, soffit and backing material and its fastening. All applicable failure modes including bending rupture of siding, fastener withdrawal and fastener head pull-through shall be considered in the testing or design analysis. Where the wall covering, soffit and backing material resist wind load as an assembly, use of the design capacity of the assembly shall be permitted.

R703.2 Water-Resistive Barrier

One layer of No. 15 asphalt felt, free from holes and breaks, complying with ASTM D226 for Type 1 felt or other approved water-resistive barrier shall be applied over studs or sheathing of all exterior walls. No.15 asphalt felt shall be applied horizontally, with the upper layer lapped over the lower layer not less than 2 inches (51 mm). Where joints occur, felt shall be lapped not less than 6 inches (152 mm). Other approved materials shall be installed in accordance with the water-resistive barrier manufacturer's installation instructions. The No. 15 asphalt felt or other approved water-resistive barrier material shall be continuous to the top of walls and terminated at penetrations and building appendages in a manner to meet the requirements of the exterior wall envelope as described in Section R703.1.

R703.3 Wall Covering Nominal Thickness and Attachments

The nominal thickness and attachment of exterior wall coverings shall be in accordance with Table R703.3(1), the wall covering material requirements of this section, and the wall covering manufacturer's installation instructions. Cladding attachment over foam sheathing shall comply with the additional requirements and limitations of Sections R703.15 through R703.17. Nominal material thicknesses in Table R703.3(1) are based on a maximum stud spacing of 16 inches (406 mm) on center. Where specified by the siding manufacturer's instructions and supported by a test report or other documentation, attachment to studs with greater spacing is permitted. Fasteners for exterior wall coverings attached to wood framing shall be in accordance with Section R703.3.3 and Table R703.3(1). Exterior wall coverings shall be attached to cold-formed steel light frame construction in accordance with the cladding manufacturer's installation instructions, the requirements of Table R703.3(1) using screw fasteners substituted for the nails specified in accordance with Table R703.3(2), or an approved design.

TABLE R703.3(1)
SIDING MINIMUM ATTACHMENT AND MINIMUM THICKNESS
SIDING MATERIAL NOMINAL
THICKNESS
(inches)
 JOINT
TREATMENT
 TYPE OF SUPPORTS FOR THE SIDING MATERIAL AND FASTENERS
Wood or wood
structural
panel
sheathing
into stud
 Fiberboard
sheathing
into stud
 Gypsum
sheathing
into stud
 Foam plastic
sheathing
into studl
 Direct
to studs
 Number or
spacing of
fasteners
Anchored veneer: brick, concrete, masonry or stone (see Section R703.8) 2 Section R703.8 Section R703.8
Adhered veneer: concrete, stone or masonry (see Section R703.12) — Section R703.12 Section R703.12
Fiber cement siding Panel siding (see Section R703.10.1) 5/16 Section R703.10.1 6d common
(2" × 0.113")
 6d common
(2" × 0.113")
 6d common
(2" × 0.113")
 6d common
(2" × 0.113")
 4d common
(11/2" × 0.099")
 6" panel edges 12" inter. sup.
Lap siding (see Section R703.10.2) 5/16 Section R703.10.2 6d common
(2" × 0.113")
 6d common
(2" × 0.113")
 6d common
(2" × 0.113")
 6d common
(2" × 0.113")
 6d common
(2" × 0.113")
or 11 gage roofing nail		 Note f
Hardboard panel siding (see Section R703.5) 7/16 — 0.120" nail (shank) with 0.225" head 0.120" nail (shank) with 0.225" head 0.120" nail (shank) with 0.225" head 0.120" nail (shank) with 0.225" head 0.120" nail (shank) with 0.225" head 6" panel edges 12" inter. sup.d
Hardboard lap siding (see Section R703.5) 7/16 Note e 0.099" nail (shank) with 0.240" head 0.099" nail (shank) with 0.240" head 0.099" nail (shank) with 0.240" head 0.099" nail (shank) with 0.240" head 0.099" nail (shank) with 0.240" head Same as stud spacing 2 per bearing
Horizontal aluminuma Without
insulation
 0.019b Lap Siding nail
11/2" × 0.120"
 Siding nail
2" × 0.120"
 Siding nail
2" × 0.120"
 Siding nailh
11/2" × 0.120"
 Not allowed Same as stud spacing
0.024 Lap Siding nail
11/2" × 0.120"
 Siding nail
2" × 0.120"
 Siding nail
2" × 0.120"
 Siding nailh
11/2" × 0.120"
 Not allowed
With
insulation
 0.019 Lap Siding nail
11/2" × 0.120"
 Siding nail
21/2" × 0.120"
 Siding nail
21/2" × 0.120"
 Siding nailh
11/2" × 0.120"
 Siding nail
11/2" × 0.120"
Insulated vinyl sidingj 0.035
(vinyl
siding
layer only)
 Lap 0.120 nail (shank) with a 0.313 head or 16-gage crownh, i 0.120 nail (shank) with a 0.313 head or 16-gage crownh 0.120 nail (shank) with a 0.313 head or 16-gage crownh 0.120 nail (shank) with a 0.313 head Section R703.11.2 Not allowed 16 inches on center or specified by manufacturer instructions, test report or other sections of this code
Particleboard panels 3/8 — 6d box nail
(2" × 0.099")
 6d box nail
(2" × 0.099")
 6d box nail
(2" × 0.099")
 6d box nail
(2" × 0.099")
 Not allowed 6" panel edges 12" inter. sup.
1/2 — 6d box nail
(2" × 0.099")
 6d box nail
(2" × 0.099")
 6d box nail
(2" × 0.099")
 6d box nail
(2" × 0.099")
 6d box nail
(2" × 0.099")
5/8 — 6d box nail
(2" × 0.099")
 8d box nail
(21/2" × 0.113")
 8d box nail
(21/2" × 0.113")
 6d box nail
(2" × 0.099")
 6d box nail
(2" × 0.099")
Polypropylene sidingk Not
applicable
 Lap Section 703.14.1 Section 703.14.1 Section 703.14.1 Section 703.14.1 Not
allowed
 As specified by the manufacturer instructions, test report or other sections of this code
Steelc 29 ga. Lap Siding nail (13/4" × 0.113") Staple—13/4" Siding nail (23/4" × 0.113") Staple—21/2" Siding nail (21/2" × 0.113") Staple—21/4" Siding nail (13/4" × 0.113") Staple—13/4" Not allowed Same as stud spacing
Vinyl siding (see Section R703.11) 0.035 Lap 0.120" nail (shank) with a 0.313" head or 16-gage staple with 3/8- to 1/2-inch crownh, i 0.120" nail (shank) with a 0.313" head or 16-gage staple with 3/8- to 1/2-inch crownh 0.120" nail (shank) with a 0.313" head or 16- gage staple with 3/8- to 1/2-inch crownh 0.120" nail (shank) with a 0.313 head Section R703.11.2 Not allowed 16 inches on center or as specified by the manufacturer instructions or test report
Wood siding (see Section R703.5) Wood rustic, drop 3/8 min. Lap 6d box or siding nail
(2" × 0.099")
 6d box or siding nail
(2" × 0.099")
 6d box or siding nail
(2" × 0.099")
 6d box or siding nail
(2" × 0.099")
 8d box or siding nail
(21/2" × 0.113")
Staple—2"		 Face nailing up to 6" widths, 1 nail per bearing; 8" widths and over, 2 nails per bearing
Shiplap 19/32 average Lap
Bevel 7/16
Butt tip 3/16 Lap
Wood structural panel ANSI/APA PRP-210 siding (exterior grade) (see Section R703.5) 3/8 — 1/2 Note e 2" × 0.099"
siding nail
 21/2" × 0.113"
siding nail
 21/2" × 0.113"
siding nail
 21/2" × 0.113"
siding nail
 2" × 0.099"
siding nail
 6" panel edges 12" inter. sup.
Wood structural panel lap siding (see Section R703.5) 3/8 — 1/2 Note e
Note g
 2" × 0.099"
siding nail
 21/2" × 0.113"
siding nail
 21/2" × 0.113"
siding nail
 21/2" × 0.113"
siding nail
 2" × 0.099"
siding nail
 8" along bottom edge
For SI: 1 inch = 25.4 mm.
  1. Aluminum nails shall be used to attach aluminum siding.
  2. Aluminum (0.019 inch) shall be unbacked only where the maximum panel width is 10 inches and the maximum flat area is 8 inches. The tolerance for aluminum siding shall be +0.002 inch of the nominal dimension.
  3. Shall be of approved type.
  4. Where used to resist shear forces, the spacing must be 4 inches at panel edges and 8 inches on interior supports.
  5. Vertical end joints shall occur at studs and shall be covered with a joint cover or shall be caulked.
  6. Face nailing: one 6d common nail through the overlapping planks at each stud. Concealed nailing: one 11-gage 11/2-inch-long galv. roofing nail through the top edge of each plank at each stud in accordance with the manufacturer's installation instructions.
  7. Vertical joints, if staggered, shall be permitted to be away from studs if applied over wood structural panel sheathing.
  8. Minimum fastener length must be sufficient to penetrate sheathing other nailable substrate and framing a total of a minimum of 11/4 inches or in accordance with the manufacturer's installation instructions.
  9. Where specified by the manufacturer's instructions and supported by a test report, fasteners are permitted to penetrate into or fully through nailable sheathing or other nailable substrate of minimum thickness specified by the instructions or test report, without penetrating into framing.
  10. Insulated vinyl siding shall comply with ASTM D7793.
  11. Polypropylene siding shall comply with ASTM D7254.
  12. Cladding attachment over foam sheathing shall comply with the additional requirements and limitations of Sections R703.15, R703.16 and R703.17.
TABLE R703.3(2)
SCREW FASTENER SUBSTITUTION FOR SIDING ATTACHMENT TO COLD-FORMED STEEL LIGHT FRAME CONSTRUCTIONa, b, c, d, e
NAIL DIAMETER
PER TABLE R703.3(1)		 MINIMUM SCREW
FASTENER SIZE
0.099"
No. 6
0.113"
No. 7
0.120"
No. 8
For SI: 1 inch = 25.4 mm
  1. Screws shall comply with ASTM C1513 and shall penetrate a minimum of three threads through minimum 33 mil (20 gage) cold-formed steel frame construction.
  2. Screw head diameter shall be not less than the nail head diameter required by Table R703.3(1).
  3. Number and spacing of screw fasteners shall comply with Table R703.3(1).
  4. Pan head, hex washer head, modified truss head or other screw head types with a flat attachment surface under the head shall be used for vinyl siding attachment.
  5. Aluminum siding shall not be fastened directly to cold-formed steel light frame construction.

R703.3.1 Soffit Installation

Soffits shall comply with Section R703.3.1.1, Section R703.3.1.2 or the manufacturer's installation instructions.

R703.3.1.1 Wood Structural Panel Soffit

The minimum nominal thickness for wood structural panel soffits shall be 3/8 inch (9.5 mm) and shall be fastened to framing or nailing strips with 2-inch by 0.099-inch (51 mm × 2.5 mm) nails. Fasteners shall be in spaced not less than 6 inches (152 mm) on center at panel edges and 12 inches (305 mm) on center at intermediate supports.

R703.3.1.2 Vinyl Soffit Panels

Soffit panels shall be fastened at fascia and wall ends and to intermediate nailing strips as necessary to ensure that there is no unsupported span greater than 16 inches (406 mm), or as specified by the manufacturer's instructions.

R703.3.2 Wind Limitations

Where the design wind pressure exceeds 30 psf or where the limits of Table R703.3.2 are exceeded, the attachment of wall coverings and soffits shall be designed to resist the component and cladding loads specified in Table R301.2(2) for walls, adjusted for height and exposure in accordance with Table R301.2(3). For the determination of wall covering and soffit attachment, component and cladding loads shall be determined using an effective wind area of 10 square feet (0.93 m2).
TABLE R703.3.2
LIMITS FOR ATTACHMENT PER TABLE R703.3(1)
MAXIMUM MEAN ROOF HEIGHT
Ultimate Wind Speed
(mph 3-second gust)
Exposure
BCD
115NL50'20'
120NL30'DR
13060'15'DR
14035'DRDR
For SI: 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.
NL = Not Limited by Table R703.3.2, DR = Design Required.

R703.3.3 Fasteners

Exterior wall coverings and roof overhang soffits shall be securely fastened with aluminum, galvanized, stainless steel or rust-preventative coated nails or staples in accordance with Table R703.3(1) or with other approved corrosion-resistant fasteners in accordance with the wall covering manufacturer's installation instructions. Nails and staples shall comply with ASTM F1667. Nails shall be T-head, modified round head, or round head with smooth or deformed shanks. Staples shall have a minimum crown width of 7/16 inch (11.1 mm) outside diameter and be manufactured of minimum 16-gage wire. Where fiberboard, gypsum, or foam plastic sheathing backing is used, nails or staples shall be driven into the studs. Where wood or wood structural panel sheathing is used, fasteners shall be driven into studs unless otherwise permitted to be driven into sheathing in accordance with either the siding manufacturer's installation instructions or Table R703.3.3.
TABLE R703.3.3
OPTIONAL SIDING ATTACHMENT SCHEDULE FOR FASTENERS WHERE NO STUD PENETRATION NECESSARY
APPLICATION NUMBER AND TYPE OF FASTENER SPACING OF FASTENERSb
Exterior wall covering (weighing 3 psf or less) attachment to wood structural panel sheathing, either direct or over foam sheathing a maximum of 2 inches thick.a
Note: Does not apply to vertical siding.
 Ring shank roofing nail (0.120" min. dia.) 12" o.c.
Ring shank nail (0.148" min. dia.) 15" o.c.
No. 6 screw (0.138" min. dia.) 12" o.c.
No. 8 screw (0.164" min. dia.) 16" o.c.
For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.479 kPa.
  1. Fastener length shall be sufficient to penetrate the back side of the wood structural panel sheathing by at least 1/4 inch. The wood structural panel sheathing shall be not less than 7/16 inch in thickness.
  2. Spacing of fasteners is per 12 inches of siding width. For other siding widths, multiply "Spacing of Fasteners" above by a factor of 12/s, where "s" is the siding width in inches. Fastener spacing shall never be greater than the manufacturer's minimum recommendations.

R703.3.4 Minimum Fastener Length and Penetration

Fasteners shall have the greater of the minimum length specified in Table R703.3(1) or as required to provide a minimum penetration into framing as follows:
  1. Fasteners for horizontal aluminum siding, steel siding, particleboard panel siding, wood structural panel siding in accordance with ANSI/APA-PRP 210, fiber-cement panel siding and fiber-cement lap siding installed over foam plastic sheathing shall penetrate not less than 11/2 inches (38 mm) into framing or shall be in accordance with the manufacturer's installation instructions.
  2. Fasteners for hardboard panel and lap siding shall penetrate not less than 11/2 inches (38 mm) into framing.
  3. Fasteners for vinyl siding and insulated vinyl siding installed over wood or wood structural panel sheathing shall penetrate not less than 11/4 inches (32 mm) into sheathing and framing combined. Vinyl siding and insulated vinyl siding shall be permitted to be installed with fasteners penetrating into or through wood or wood structural sheathing of minimum thickness as specified by the manufacturer's instructions or test report, with or without penetration into the framing. Where the fastener penetrates fully through the sheathing, the end of the fastener shall extend not less than 1/4 inch (6.4 mm) beyond the opposite face of the sheathing. Fasteners for vinyl siding and insulated vinyl siding installed over foam plastic sheathing shall be in accordance with Section R703.11.2. Fasteners for vinyl siding and insulated vinyl siding installed over fiberboard or gypsum sheathing shall penetrate not less than 11/4 inches (32 mm) into framing.
  4. Fasteners for vertical or horizontal wood siding shall penetrate not less than 11/2 inches (38 mm) into studs, studs and wood sheathing combined, or blocking.
  5. Fasteners for siding material installed over foam plastic sheathing shall have sufficient length to accommodate foam plastic sheathing thickness and to penetrate framing or sheathing and framing combined, as specified in Items 1 through 4.

R703.4 Flashing

Approved corrosion-resistant flashing shall be applied shingle-fashion in a manner to prevent entry of water into the wall cavity or penetration of water to the building structural framing components. Self-adhered membranes used as flashing shall comply with AAMA 711. Fluid-applied membranes used as flashing in exterior walls shall comply with AAMA 714. The flashing shall extend to the surface of the exterior wall finish. Approved corrosion-resistant flashings shall be installed at the following locations:
  1. Exterior window and door openings. Flashing at exterior window and door openings shall extend to the surface of the exterior wall finish or to the water-resistive barrier complying with Section 703.2 for subsequent drainage. Mechanically attached flexible flashings shall comply with AAMA 712. Flashing at exterior window and door openings shall be installed in accordance with one or more of the following:
    1. The fenestration manufacturer's installation and flashing instructions, or for applications not addressed in the fenestration manufacturer's instructions, in accordance with the flashing manufacturer's instructions. Where flashing instructions or details are not provided, pan flashing shall be installed at the sill of exterior window and door openings. Pan flashing shall be sealed or sloped in such a manner as to direct water to the surface of the exterior wall finish or to the water-resistive barrier for subsequent drainage. Openings using pan flashing shall incorporate flashing or protection at the head and sides.
    2. In accordance with the flashing design or method of a registered design professional.
    3. In accordance with other approved methods.
  2. At the intersection of chimneys or other masonry construction with frame or stucco walls, with projecting lips on both sides under stucco copings.
  3. Under and at the ends of masonry, wood or metal copings and sills.
  4. Continuously above all projecting wood trim.
  5. Where exterior porches, decks or stairs attach to a wall or floor assembly of wood-frame construction.
  6. At wall and roof intersections.
  7. At built-in gutters.

R703.5 Wood, Hardboard and Wood Structural Panel Siding

Wood, hardboard, and wood structural panel siding shall be installed in accordance with this section and Table R703.3(1). Hardboard siding shall comply with CPA/ANSI A135.6. Hardboard siding used as architectural trim shall comply with CPA/ANSI A 135.7.

R703.5.1 Vertical Wood Siding

Wood siding applied vertically shall be nailed to horizontal nailing strips or blocking set not more than 24 inches (610 mm) on center.

R703.5.2 Panel Siding

Three-eighths-inch (9.5 mm) wood structural panel siding shall not be applied directly to studs spaced more than 16 inches (406 mm) on center where long dimension is parallel to studs. Wood structural panel siding 7/16 inch (11.1 mm) or thinner shall not be applied directly to studs spaced more than 24 inches (610 mm) on center. The stud spacing shall not exceed the panel span rating provided by the manufacturer unless the panels are installed with the face grain perpendicular to the studs or over sheathing approved for that stud spacing.
Joints in wood, hardboard or wood structural panel siding shall be made as follows unless otherwise approved. Vertical joints in panel siding shall occur over framing members, unless wood or wood structural panel sheathing is used, and shall be shiplapped or covered with a batten. Horizontal joints in panel siding shall be lapped not less than 1 inch (25 mm) or shall be shiplapped or flashed with Z-flashing and occur over solid blocking, wood or wood structural panel sheathing.

R703.5.3 Horizontal Wood Siding

Horizontal lap siding shall be installed in accordance with the manufacturer's recommendations. Where there are no recommendations the siding shall be lapped not less than 1 inch (25 mm), or 1/2 inch (12.7 mm) if rabbeted, and shall have the ends caulked, covered with a batten or sealed and installed over a strip of flashing.

R703.6 Wood Shakes and Shingles

Wood shakes and shingles shall conform to CSSB.

R703.6.1 Application

Wood shakes or shingles shall be applied either single course or double course over nominal 1/2-inch (12.7 mm) wood-based sheathing or to furring strips over 1/2-inch (12.7 mm) nominal nonwood sheathing. A water-resistive barrier shall be provided over all sheathing, with horizontal overlaps in the membrane of not less than 2 inches (51 mm) and vertical overlaps of not less than 6 inches (152 mm). Where horizontal furring strips are used, they shall be 1 inch by 3 inches or 1 inch by 4 inches (25 mm by 76 mm or 25 mm by 102 mm) and shall be fastened to the studs with minimum 7d or 8d box nails and shall be spaced a distance on center equal to the actual weather exposure of the shakes or shingles, not to exceed the maximum exposure specified in Table R703.6.1. When installing shakes or shingles over a nonpermeable water-resistive barrier, furring strips shall be placed first vertically over the barrier and in addition, horizontal furring strips shall be fastened to the vertical furring strips prior to attaching the shakes or shingles to the horizontal furring strips. The spacing between adjacent shingles to allow for expansion shall be 1/8 inch (3.2 mm) to 1/4 inch (6.4 mm) apart, and between adjacent shakes shall be 3/8 inch (9.5 mm) to 1/2 inch (12.7 mm) apart. The offset spacing between joints in adjacent courses shall be not less than 11/2 inches (38 mm).
TABLE R703.6.1
MAXIMUM WEATHER EXPOSURE FOR WOOD SHAKES AND SHINGLES ON EXTERIOR WALLSa, b, c (Dimensions are in inches)
LENGTHEXPOSURE
FOR SINGLE COURSE
EXPOSURE
FOR DOUBLE COURSE
Shinglesa
16712b
18814c
24101/216d
Shakesa
18814
24101/218
For SI: 1 inch = 25.4 mm.
  1. Dimensions given are for No. 1 grade.
  2. A maximum 9-inch exposure is permitted for No. 2 grade.
  3. A maximum 10-inch exposure is permitted for No. 2 grade.
  4. A maximum 14-inch exposure is permitted for No. 2 grade.

R703.6.2 Weather Exposure

The maximum weather exposure for shakes and shingles shall not exceed that specified in Table R703.6.1.

R703.6.3 Attachment

Wood shakes or shingles shall be installed according to this chapter and the manufacturer's instructions. Each shake or shingle shall be held in place by two stainless steel Type 304, Type 316 or hot-dipped zinc-coated galvanized corrosion-resistant box nails in accordance with Table R703.6.3(1) or R703.6.3(2). The hot-dipped zinc-coated galvanizing shall be in compliance with ASTM A153, 1.0 ounce per square foot. Alternatively, 16-gage stainless steel Type 304 or Type 316 staples with crown widths 7/16 inch (11 mm) minimum, 3/4 inch (19 mm) maximum, shall be used and the crown of the staple shall be placed parallel with the butt of the shake or the shingle. In single-course application, the fasteners shall be concealed by the course above and shall be driven approximately 1 inch (25 mm) above the butt line of the succeeding course and 3/4 inch (19 mm) from the edge. In double-course applications, the exposed shake or shingle shall be face-nailed with two fasteners, driven approximately 2 inches (51 mm) above the butt line and 3/4 inch (19 mm) from each edge. Fasteners installed within 15 miles (24 km) of salt water coastal areas shall be stainless steel Type 316. Fasteners for fire-retardant-treated shakes or shingles in accordance with Section R902 or pressure-impregnated-preservative-treated shakes or shingles in accordance with AWPA U1 shall be stainless steel Type 316. The fasteners shall penetrate the sheathing or furring strips by not less than 1/2 inch (13 mm) and shall not be overdriven. Fasteners for untreated (natural) and treated products shall comply with ASTM F1667.
TABLE R703.6.3(1)
SINGLE-COURSE SIDEWALL FASTENERS
SINGLE-COURSE SIDEWALL FASTENERS
Product typeNail type and minimum length
(inches)
Minimum head diameter
(inches)
Minimum shank thickness
(inches)
R & R and sanded shingles
16" and 18" shingles3d box 11/40.190.08
24" shingles4d box 11/20.190.08
Grooved shingles
16" and 18" shingles3d box 11/40.190.08
24" shingles4d box 11/20.190.08
Split and sawn shakes
18" straight-split shakes5d box 13/40.190.08
18" and 24" handsplit shakes6d box 20.190.0915
24" tapersplit shakes5d box 13/40.190.08
18" and 24" tapersawn shakes6d box 20.190.0915
For SI: 1 inch = 25.4 mm.
TABLE R703.6.3(2)
DOUBLE-COURSE SIDEWALL FASTENERS
DOUBLE-COURSE SIDEWALL FASTENERS
Product typeNail type and minimum length
(inches)
Minimum head diameter
(inches)
Minimum shank thickness
(inches)
R & R and sanded shingles
16," 8" and 24" shingles5d box 13/4 or same size casing nails0.190.08
Grooved shingles
16," 18" and 24"shingles5d box 13/40.190.08
Split and sawn shakes
18" straight-split shakes7d box 21/4 or 8d 21/20.190.099
18" and 24" handsplit shakes7d box 21/4 or 8d 21/20.190.099
24" tapersplit shakes7d box 21/4 or 8d 21/20.190.099
18" and 24" tapersawn shakes7d box 21/4 or 8d 21/20.190.099
For SI: 1 inch = 25.4 mm.

R703.6.4 Bottom Courses

The bottom courses shall be doubled.

R703.7 Exterior Plaster (Stucco)

Installation of exterior plaster shall be in compliance with ASTM C926, ASTM C1063 and the provisions of this code.

R703.7.1 Lath

Lath and lath attachments shall be of corrosion-resistant materials. Expanded metal or woven wire lath shall be attached with 11/2-inch-long (38 mm), 11-gage nails having a 7/16-inch (11.1 mm) head, or 7/8-inch-long (22.2 mm), 16-gage staples, spaced not more than 6 inches (152 mm) or as otherwise approved.
Exception: Lath is not required over masonry, cast-in-place concrete, precast concrete or stone substrates prepared in accordance with ASTM C1063.

R703.7.2 Plaster

Plastering with cement plaster shall be in accordance with ASTM C926. Cement materials shall be in accordance with one of the following:
  1. Masonry cement conforming to ASTM C91 Type M, S or N.
  2. Portland cement conforming to ASTM C150 Type I, II, or III.
  3. Blended hydraulic cement conforming to ASTM C595 Type IP, IS (< 70), IL, or IT (S < 70).
  4. Hydraulic cement conforming to ASTM C1157 Type GU, HE, MS, HS, or MH.
  5. Plastic (stucco) cement conforming to ASTM C1328.
Plaster shall be not less than three coats where applied over metal lath or wire lath and shall be not less than two coats where applied over masonry, concrete, pressure-preservative-treated wood or decay-resistant wood as specified in Section R317.1 or gypsum backing. If the plaster surface is completely covered by veneer or other facing material or is completely concealed, plaster application need be only two coats, provided the total thickness is as set forth in Table R702.1(1).
On wood-frame construction with an on-grade floor slab system, exterior plaster shall be applied to cover, but not extend below, lath, paper and screed.
The proportion of aggregate to cementitious materials shall be as set forth in Table R702.1(3).

R703.7.2.1 Weep Screeds

A minimum 0.019-inch (0.5 mm) (No. 26 galvanized sheet gage), corrosion-resistant weep screed or plastic weep screed, with a minimum vertical attachment flange of 31/2 inches (89 mm), shall be provided at or below the foundation plate line on exterior stud walls in accordance with ASTM C926. The weep screed shall be placed not less than 4 inches (102 mm) above the earth or 2 inches (51 mm) above paved areas and shall be of a type that will allow trapped water to drain to the exterior of the building. The weather-resistant barrier shall lap the attachment flange. The exterior lath shall cover and terminate on the attachment flange of the weep screed.

R703.7.3 Water-Resistive Barriers

Water-resistive barriers shall be installed as required in Section R703.2 and, where applied over wood-based sheathing, shall include a water-resistive, vapor-permeable barrier with a performance at least equivalent to two layers of Grade D paper. The individual layers shall be installed independently such that each layer provides a separate continuous plane and any flashing, installed in accordance with Section R703.4 and intended to drain to the water-resistive barrier, is directed between the layers.
Exception: Where the water-resistive barrier that is applied over wood-based sheathing has a water resistance equal to or greater than that of 60-minute Grade D paper and is separated from the stucco by an intervening, substantially nonwater-absorbing layer or designed drainage space.

R703.7.4 Application

Each coat shall be kept in a moist condition for at least 48 hours prior to application of the next coat.
Exception: Applications installed in accordance with ASTM C926.

R703.7.5 Curing

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

R703.8 Anchored Stone and Masonry Veneer, General

Anchored stone and masonry veneer shall be installed in accordance with this chapter, Table R703.3(1) and Figure R703.8. These veneers installed over a backing of wood or cold-formed steel shall be limited to the first story above grade plane and shall not exceed 5 inches (127 mm) in thickness. See Section R602.10 for wall bracing requirements for masonry veneer for wood-framed construction and Section R603.9.5 for wall bracing requirements for masonry veneer for cold-formed steel construction.

Exceptions:
  1. For buildings in Seismic Design Categories A, B and C, exterior stone or masonry veneer, as specified in Table R703.8(1), with a backing of wood or steel framing shall be permitted to the height specified in Table R703.8(1) above a noncombustible foundation.
  2. For detached one- or two-family dwellings in Seismic Design Categories D0, D1 and D2, exterior stone or masonry veneer, as specified in Table R703.8(2), with a backing of wood framing shall be permitted to the height specified in Table R703.8(2) above a noncombustible foundation.
For SI: 1 inch = 24.5 mm.
For SI: 1 inch = 25.4 mm.
  1. See Sections R703.4, R703.8.5 and R703.8.6.
  2. See Sections R703.2 and R703.8.4.
  3. See Table R703.8.4 and Section R703.8.4.2.
  4. See Section R703.8.3.
  5. Figure R703.8 illustrates typical construction details for a masonry veneer wall. For the actual mandatory requirements of this code, see the indicated sections of text. Other details of masonry veneer wall construction shall be permitted provided the requirements of the indicated sections of text are met.
FIGURE R703.8
TYPICAL MASONRY VENEER WALL DETAILSe


TABLE R703.8(1)
STONE OR MASONRY VENEER LIMITATIONS AND REQUIREMENTS, WOOD OR STEEL FRAMING, SEISMIC DESIGN CATEGORIES A, B AND C
SEISMIC DESIGN
CATEGORY
 NUMBER OF
WOOD- OR STEEL-

FRAMED STORIES
 MAXIMUM HEIGHT OF
VENEER ABOVE

NONCOMBUSTIBLE

FOUNDATIONa (feet)
 MAXIMUM NOMINAL
THICKNESS OF

VENEER (inches)
 MAXIMUM WEIGHT OF
VENEER (psf)b
 WOOD- OR STEEL-
FRAMED STORY
A or B Steel: 1 or 2
Wood: 1, 2 or 3
 30 5 50 all
C 1 30 5 50 1 only
2 30 5 50 top
bottom
Wood only: 3 30 5 50 top
middle
bottom
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.479 kPa.
  1. An additional 8 feet is permitted for gable end walls. See also story height limitations of Section R301.3.
  2. Maximum weight is installed weight and includes weight of mortar, grout, lath and other materials used for installation. Where veneer is placed on both faces of a wall, the combined weight shall not exceed that specified in this table.
TABLE R703.8(2)
STONE OR MASONRY VENEER LIMITATIONS AND REQUIREMENTS, ONE- AND TWO-FAMILY DETACHED DWELLINGS, SEISMIC DESIGN CATEGORIES D0, D1 AND D2
SEISMIC DESIGN
CATEGORY
 NUMBER OF WOOD-
FRAMED STORIESa
 MAXIMUM HEIGHT OF
VENEER ABOVE

NONCOMBUSTIBLE

FOUNDATION OR

FOUNDATION WALL (feet)
 MAXIMUM NOMINAL
THICKNESS OF VENEER

(inches)
 MAXIMUM WEIGHT OF
VENEER

(psf)b
D0 1 20c 4 40
2 20c 4 40
3 30d 4 40
D1 1 20c 4 40
2 20c 4 40
3 20c 4 40
D2 1 20c 3 30
2 20c 3 30
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.479 kPa, 1 pound-force = 4.448 N.
  1. Cripple walls are not permitted in Seismic Design Categories D0, D1 and D2.
  2. Maximum weight is installed weight and includes weight of mortar, grout and lath, and other materials used for installation.
  3. The veneer shall not exceed 20 feet in height above a noncombustible foundation, with an additional 8 feet permitted for gable end walls, or 30 feet in height with an additional 8 feet for gable end walls where the lower 10 feet have a backing of concrete or masonry wall. See story height limitations of Section R301.3.
  4. The veneer shall not exceed 30 feet in height above a noncombustible foundation, with an additional 8 feet permitted for gable end walls. See story height limitations of Section R301.3.

R703.8.1 Interior Veneer Support

Veneers used as interior wall finishes shall be permitted to be supported on wood or cold-formed steel floors that are designed to support the loads imposed.

R703.8.2 Exterior Veneer Support

Except in Seismic Design Categories D0, D1 and D2, exterior masonry veneers having an installed weight of 40 pounds per square foot (195 kg/m2) or less shall be permitted to be supported on wood or cold-formed steel construction. Where masonry veneer supported by wood or cold-formed steel construction adjoins masonry veneer supported by the foundation, there shall be a movement joint between the veneer supported by the wood or cold-formed steel construction and the veneer supported by the foundation. The wood or cold-formed steel construction supporting the masonry veneer shall be designed to limit the deflection to 1/600 of the span for the supporting members. The design of the wood or cold-formed steel construction shall consider the weight of the veneer and any other loads.

R703.8.2.1 Support by Steel Angle

A minimum 6-inch by 4-inch by 5/16-inch (152 mm by 102 mm by 8 mm) steel angle, with the long leg placed vertically, shall be anchored to double 2-inch by 4-inch (51 mm by 102 mm) wood studs or double 350S162 cold-formed steel studs at a maximum on-center spacing of 16 inches (406 mm). Anchorage of the steel angle at every double stud spacing shall be not less than two 7/16-inch-diameter (11 mm) by 4-inch (102 mm) lag screws for wood construction or two 7/16-inch (11.1 mm) bolts with washers for cold-formed steel construction. The steel angle shall have a minimum clearance to underlying construction of 1/16 inch (1.6 mm). Not less than two-thirds the width of the masonry veneer thickness shall bear on the steel angle. Flashing and weep holes shall be located in the masonry veneer in accordance with Figure R703.8.2.1. The maximum height of masonry veneer above the steel angle support shall be 12 feet 8 inches (3861 mm). The airspace separating the masonry veneer from the wood backing shall be in accordance with Sections R703.8.4 and R703.8.4.2. The method of support for the masonry veneer on wood construction shall be constructed in accordance with Figure R703.8.2.1.
The maximum slope of the roof construction without stops shall be 7:12. Roof construction with slopes greater than 7:12 but not more than 12:12 shall have stops of a minimum 3-inch by 3-inch by 1/4-inch (76 mm by 76 mm by 6.4 mm) steel plate welded to the angle at 24 inches (610 mm) on center along the angle or as approved by the building official.
FIGURE R703.8.2.1
EXTERIOR MASONRY VENEER SUPPORT BY STEEL ANGLES

R703.8.2.2 Support by Roof Construction

A steel angle shall be placed directly on top of the roof construction. The roof supporting construction for the steel angle shall consist of not fewer than three 2-inch by 6-inch (51 mm by 152 mm) wood members for wood construction or three 550S162 cold-formed steel members for cold-formed steel light frame construction. A wood member abutting the vertical wall stud construction shall be anchored with not fewer than three 5/8-inch (15.9 mm) diameter by 5-inch (127 mm) lag screws to every wood stud spacing. Each additional wood roof member shall be anchored by the use of two 10d nails at every wood stud spacing. A cold-formed steel member abutting the vertical wall stud shall be anchored with not fewer than nine No. 8 screws to every cold-formed steel stud. Each additional cold-formed steel roof member shall be anchored to the adjoining roof member using two No. 8 screws at every stud spacing. Not less than two-thirds the width of the masonry veneer thickness shall bear on the steel angle. Flashing and weep holes shall be located in the masonry veneer wythe in accordance with Figure R703.8.2.2. The maximum height of the masonry veneer above the steel angle support shall be 12 feet 8 inches (3861 mm). The airspace separating the masonry veneer from the wood backing shall be in accordance with Sections R703.8.4 and R703.8.4.2. The support for the masonry veneer shall be constructed in accordance with Figure R703.8.2.2.
The maximum slope of the roof construction without stops shall be 7:12. Roof construction with slopes greater than 7:12 but not more than 12:12 shall have stops of a minimum 3-inch by 3-inch by 1/4-inch (76 mm by 76 mm by 6.4 mm) steel plate welded to the angle at 24 inches (610 mm) on center along the angle or as approved by the building official.
FIGURE R703.8.2.2
EXTERIOR MASONRY VENEER SUPPORT BY ROOF MEMBERS

R703.8.3 Lintels

Masonry veneer shall not support any vertical load other than the dead load of the veneer above. Veneer above openings shall be supported on lintels of noncombustible materials. The lintels shall have a length of bearing not less than 4 inches (102 mm). Steel lintels shall be shop coated with a rust-inhibitive paint, except for lintels made of corrosion-resistant steel or steel treated with coatings to provide corrosion resistance. Construction of openings shall comply with either Section R703.8.3.1 or 703.8.3.2.

R703.8.3.1 Allowable Span

The allowable span shall not exceed the values set forth in Table R703.8.3.1.
TABLE R703.8.3.1
ALLOWABLE SPANS FOR LINTELS SUPPORTING MASONRY VENEERa, b, c, d
SIZE OF STEEL ANGLEa, c, d
(inches)
 NO STORY ABOVE ONE STORY ABOVE TWO STORIES ABOVE NO. OF 1/2-INCH OR EQUIVALENT
REINFORCING BARS IN REINFORCED LINTELb, d
3 × 3 × 1/4 6'-0" 4'-6" 3'-0" 1
4 × 3 × 1/4 8'-0" 6'-0" 4'-6" 1
5 × 31/2 × 5/16 10'-0" 8'-0" 6'-0" 2
6 × 31/2 × 5/16 14'-0" 9'-6" 7'-0" 2
2-6 × 31/2 × 5/16 20'-0" 12'-0" 9'-6" 4
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
  1. Long leg of the angle shall be placed in a vertical position.
  2. Depth of reinforced lintels shall be not less than 8 inches and all cells of hollow masonry lintels shall be grouted solid. Reinforcing bars shall extend not less than 8 inches into the support.
  3. Steel members indicated are adequate typical examples; other steel members meeting structural design requirements shall be permitted to be used.
  4. Either steel angle or reinforced lintel shall span opening.

R703.8.3.2 Maximum Span

The allowable span shall not exceed 18 feet 3 inches (5562 mm) and shall be constructed to comply with Figure R703.8.3.2 and the following:
  1. Provide a minimum length of 18 inches (457 mm) of masonry veneer on each side of opening as shown in Figure R703.8.3.2.
  2. Provide a minimum 5-inch by 31/2-inch by 5/16-inch (127 mm by 89 mm by 7.9 mm) steel angle above the opening and shore for a minimum of 7 days after installation.
  3. Provide double-wire joint reinforcement extending 12 inches (305 mm) beyond each side of the opening. Lap splices of joint reinforcement not less than 12 inches (305 mm). Comply with one of the following:
    1. Double-wire joint reinforcement shall be 3/16-inch (4.8 mm) diameter and shall be placed in the first two bed joints above the opening.
    2. Double-wire joint reinforcement shall be 9 gauge (0.144 inch or 3.66 mm diameter) and shall be placed in the first three bed joints above the opening.
  4. Provide the height of masonry veneer above opening, in accordance with Table R703.8.3.2.
TABLE R703.8.3.2
HEIGHT OF MASONRY VENEER ABOVE OPENING
MINIMUM HEIGHT OF MASONRY
VENEER ABOVE OPENING (INCH)
 MAXIMUM HEIGHT OF MASONRY
VENEER ABOVE OPENING (FEET)
13 < 5
24 5 to < 12
60 12 to height above support
allowed by Section R703.8
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
FIGURE R703.8.3.2
MASONRY VENEER OPENING

R703.8.4 Anchorage

Masonry veneer shall be anchored to the supporting wall studs with corrosion-resistant metal ties embedded in mortar or grout and extending into the veneer a minimum of 11/2 inches (38 mm), with not less than 5/8-inch (15.9 mm) mortar or grout cover to outside face. Masonry veneer shall conform to Table R703.8.4(1). For masonry veneer tie attachment through insulating sheathing not greater than 2 inches (51 mm) in thickness to not less than 7/16 performance category wood structural panel, see Table R703.8.4(2).
TABLE R703.8.4(1)
TIE ATTACHMENT AND AIRSPACE REQUIREMENTS
BACKING AND TIEMINIMUM TIEMINIMUM TIE FASTENERaAIRSPACEc
Wood stud backing with
corrugated sheet metal
22 U.S. gage
(0.0299 in.) × 7/8 in. wide
8d common nail b
(21/2 in. × 0.131 in.)
Nominal 1 in. between
sheathing and veneer
Wood stud backing with
metal strand wire
W1.7 (No. 9 U.S. gage; 0.148 in.)
with hook embedded in mortar joint
8d common nail b
(21/2 in. × 0.131 in.)
Minimum nominal
1 in. between sheathing
and veneer
Maximum 41/2 in.
between backing
and veneer
Cold-formed steel stud
backing with adjustable
metal strand wire
W1.7 (No. 9 U.S. gage; 0.148 in.)
with hook embedded in mortar joint
No. 10 screw extending through
the steel framing a minimum of
three exposed threads
Minimum nominal
1 in. between sheathing
and veneer
Maximum 41/2 in.
between backing
and veneer
For SI: 1 inch = 25.4 mm.
  1. In Seismic Design Category D0, D1 or D2, the minimum tie fastener shall be an 8d ring-shank nail (21/2 in. × 0.131 in.) or a No. 10 screw extending through the steel framing a minimum of three exposed threads.
  2. All fasteners shall have rust-inhibitive coating suitable for the installation in which they are being used, or be manufactured from material not susceptible to corrosion.
  3. An airspace that provides drainage shall be permitted to contain mortar from construction.
TABLE R703.8.4(2)
REQUIRED BRICK TIE SPACING FOR DIRECT APPLICATION TO WOOD STRUCTURAL PANEL SHEATHINGa, b, c
FASTENER
TYPEd
SIZE
(DIA. OR

SCREW #)
REQUIRED BRICK-TIE SPACING (VERTICAL-TIE SPACING/HORIZONTAL-TIE SPACING) (inches/inches)
110 mph V Ultimate115 mph V Ultimate130 mph V Ultimate 140 mph V Ultimate
Zone 5,
Exposure B
Zone 5,
Exposure C
Zone 5,
Exposure D
Zone 5,
Exposure B
Zone 5,
Exposure C
Zone 5,
Exposure D
Zone 5,
Exposure B
Zone 5,
Exposure C
Zone 5,
Exposure D
Zone 5,
Exposure B
Zone 5,
Exposure C
Zone 5,
Exposure D
Ring
Shank
Nails
0.09116/16,
16/12,
12/16,
12/12
16/12,
12/16,
12/12
12/1216/16,
16/12,
12/16,
12/12
16/12,
12/16,
12/12
12/1216/12,
12/16,
12/12
12/12—12/12——
0.14824/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/12,
12/16,
12/12
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/12,
12/16,
12/12
12/12
Screws#624/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/12,
12/16,
12/12
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/12,
12/16,
12/12
12/12
#824/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/12,
12/16,
12/12
16/12,
12/16,
12/12
#1024/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/12,
12/16,
12/12
#1424/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
24/16,
16/24,
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
16/16,
16/12,
12/16,
12/12
For SI: 1 inch = 25.4 mm, 1 mph = 0.447 m/s.
  1. This table is based on attachment of brick ties directly to wood structural panel sheathing only. Additional attachment of the brick tie to lumber framing is not required. The brick ties shall be permitted to be placed over any insulating sheathing, not to exceed 2 inches in thickness. Wood structural panel sheathing shall be a minimum 7/16 performance category. The table is based on a building height of 30 feet or less.
  2. Wood structural panels shall have a specific gravity of 0.42 or greater in accordance with NDS.
  3. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.
  4. Fasteners shall be sized such that the tip of the fastener passes completely through the wood structural panel sheathing by not less than 1/4 inch.

R703.8.4.1 Size and Spacing

Veneer ties, if strand wire, shall be not less in thickness than No. 9 U.S. gage [(0.148 inch) (4 mm)] wire and shall have a hook embedded in the mortar joint, or if sheet metal, shall be not less than No. 22 U.S. gage by [(0.0299 inch) (0.76 mm)] 7/8 inch (22 mm) corrugated. Each tie shall support not more than 2.67 square feet (0.25 m2) of wall area and shall be spaced not more than 32 inches (813 mm) on center horizontally and 24 inches (635 mm) on center vertically.
Exception: In Seismic Design Category D0, D1 or D2 or townhouses in Seismic Design Category C or in wind areas of more than 30 pounds per square foot pressure (1.44 kPa), each tie shall support not more than 2 square feet (0.2 m2) of wall area.

R703.8.4.1.1 Veneer Ties Around Wall Openings

Additional metal ties shall be provided around wall openings greater than 16 inches (406 mm) in either dimension. Metal ties around the perimeter of openings shall be spaced not more than 3 feet (9144 mm) on center and placed within 12 inches (305 mm) of the wall opening.

R703.8.4.2 Grout Fill

As an alternative to the airspace required by Table R703.8.4, grout shall be permitted to fill the airspace. Where the airspace is filled with grout, a water-resistive barrier is required over studs or sheathing. Where the airspace is filled, replacing the sheathing and water-resistive barrier with a wire mesh and approved water-resistive barrier or an approved water-resistive barrier-backed reinforcement attached directly to the studs is permitted.

R703.8.5 Flashing

Flashing shall be located beneath the first course of masonry above finished ground level above the foundation wall or slab and at other points of support, including structural floors, shelf angles and lintels where masonry veneers are designed in accordance with Section R703.8. See Section R703.4 for additional requirements.

R703.8.6 Weepholes

Weepholes shall be provided in the outside wythe of masonry walls at a maximum spacing of 33 inches (838 mm) on center. Weepholes shall be not less than 3/16 inch (5 mm) in diameter. Weepholes shall be located immediately above the flashing.

R703.9 Exterior Insulation and Finish System (EIFS)/EIFS With Drainage

Exterior insulation and finish systems (EIFS) shall comply with this chapter and Section R703.9.1. EIFS with drainage shall comply with this chapter and Section R703.9.2.

R703.9.1 Exterior Insulation and Finish Systems (EIFS)

EIFS shall comply with the following:
  1. ASTM E2568.
  2. EIFS shall be limited to applications over substrates of concrete or masonry wall assemblies.
  3. Flashing of EIFS shall be provided in accordance with the requirements of Section R703.4.
  4. EIFS shall be installed in accordance with the manufacturer's instructions.
  5. EIFS shall terminate not less than 6 inches (152 mm) above the finished ground level.
  6. Decorative trim shall not be face-nailed through the EIFS.

R703.9.2 Exterior Insulation and Finish System (EIFS) With Drainage

EIFS with drainage shall comply with the following:
  1. ASTM E2568.
  2. EIFS with drainage shall be required over all wall assemblies with the exception of substrates of concrete or masonry wall assemblies.
  3. EIFS with drainage shall have an average minimum drainage efficiency of 90 percent when tested in accordance with ASTM E2273.
  4. The water-resistive barrier shall comply with Section R703.2 or ASTM E2570.
  5. The water-resistive barrier shall be applied between the EIFS and the wall sheathing.
  6. Flashing of EIFS with drainage shall be provided in accordance with the requirements of Section R703.4.
  7. EIFS with drainage shall be installed in accordance with the manufacturer's instructions.
  8. EIFS with drainage shall terminate not less than 6 inches (152 mm) above the finished ground level.
  9. Decorative trim shall not be face-nailed through the EIFS with drainage.

R703.10 Fiber Cement Siding

R703.10.1 Panel Siding

Fiber-cement panels shall comply with the requirements of ASTM C1186, Type A, minimum Grade II or ISO 8336, Category A, minimum Class 2. Panels shall be installed with the long dimension either parallel or perpendicular to framing. Vertical and horizontal joints shall occur over framing members and shall be protected with caulking, or with battens or flashing, or be vertical or horizontal shiplap, or otherwise designed to comply with Section R703.1. Panel siding shall be installed with fasteners in accordance with Table R703.3(1) or the approved manufacturer's instructions.

R703.10.2 Lap Siding

Fiber-cement lap siding having a maximum width of 12 inches (305 mm) shall comply with the requirements of ASTM C1186, Type A, minimum Grade II or ISO 8336, Category A, minimum Class 2. Lap siding shall be lapped a minimum of 11/4 inches (32 mm) and lap siding not having tongue-and-groove end joints shall have the ends protected with caulking, covered with an H-section joint cover, located over a strip of flashing, or shall be designed to comply with Section R703.1. Lap siding courses shall be installed with the fastener heads exposed or concealed, in accordance with Table R703.3(1) or approved manufacturer's instructions.

R703.11 Vinyl Siding

Vinyl siding shall be certified and labeled as conforming to the requirements of ASTM D3679 by an approved quality control agency.

R703.11.1 Installation

Vinyl siding, soffit and accessories shall be installed in accordance with the manufacturer's instructions.

R703.11.1.1 Fasteners

Unless specified otherwise by the manufacturer's instructions, fasteners for vinyl siding shall be 0.120-inch (3 mm) shank diameter nail with a 0.313-inch (8 mm) head or 16-gage staple with a 3/8-inch (9.5 mm) to 1/2-inch (12.7 mm) crown.

R703.11.1.2 Penetration Depth

Unless specified otherwise by the manufacturer's instructions, fasteners shall penetrate into building framing. The total penetration into sheathing, furring framing or other nailable substrate shall be a minimum 11/4 inches (32 mm). Where specified by the manufacturer's instructions and supported by a test report, fasteners are permitted to penetrate into or fully through nailable sheathing or other nailable substrate of minimum thickness specified by the instructions or test report without penetrating into framing. Where the fastener penetrates fully through the sheathing, the end of the fastener shall extend a minimum of 1/4 inch (6.4 mm) beyond the opposite face of the sheathing or nailable substrate.

R703.11.1.3 Spacing

Unless specified otherwise by the manufacturer's instructions, the maximum spacing between fasteners for horizontal siding shall be 16 inches (406 mm), and for vertical siding 12 inches (305 mm) both horizontally and vertically. Where specified by the manufacturer's instructions and supported by a test report, greater fastener spacing is permitted.

R703.11.2 Installation Over Foam Plastic Sheathing

Where vinyl siding or insulated vinyl siding is installed over foam plastic sheathing, the vinyl siding shall comply with Section R703.11 and shall have a design wind pressure resistance in accordance with Table R703.11.2.
Exceptions:
  1. Where the foam plastic sheathing is applied directly over wood structural panels, fiberboard, gypsum sheathing or other approved backing capable of independently resisting the design wind pressure, the vinyl siding shall be installed in accordance with Sections R703.3.3 and R703.11.1.
  2. Where the vinyl siding manufacturer's product specifications provide an approved design wind pressure rating for installation over foam plastic sheathing, use of this design wind pressure rating shall be permitted and the siding shall be installed in accordance with the manufacturer's installation instructions.
  3. Where the foam plastic sheathing and its attachment have a design wind pressure resistance complying with Sections R316.8 and R301.2.1, the vinyl siding shall be installed in accordance with Sections R703.3.3 and R703.11.1.
TABLE R703.11.2
ADJUSTED MINIMUM DESIGN WIND PRESSURE REQUIREMENT FOR VINYL SIDING
ULTIMATE DESIGN
WIND SPEED (MPH)
ADJUSTED MINIMUM DESIGN WIND PRESSURE (ASD) (PSF)a, b
Case 1: With interior gypsum wallboardcCase 2: Without interior gypsum wallboardc
ExposureExposure
BCDBCD
110-44.0-61.6-73.1-62.9-88.1-104.4
115-49.2-68.9-81.7-70.3-98.4-116.7
120-51.8-72.5-86.0-74.0-103.6-122.8
130-62.2-87.0-103.2-88.8-124.3-147.4
> 130Not Allowedd
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 square foot = 0.0929 m2, 1 mile per hour = 0.447 m/s, 1 pound per square foot = 0.0479 kPa.
  1. Linear interpolation is permitted.
  2. The table values are based on a maximum 30-foot mean roof height, and effective wind area of 10 square feet Wall Zone 5 (corner), and the ASD design wind pressure from Table R301.2(2) multiplied by the following adjustment factors: 2.6 (Case 1) and 3.7 (Case 2) for wind speeds less than 130 mph and 3.7 (Case 2) for wind speeds greater than 130 mph.
  3. Gypsum wallboard, gypsum panel product or equivalent.
  4. For the indicated wind speed condition, foam sheathing only on the exterior of frame walls with vinyl siding is not allowed unless the vinyl siding complies with an adjusted minimum design wind pressure requirement as determined in accordance with Note b and the wall assembly is capable of resisting an impact without puncture at least equivalent to that of a wood frame wall with minimum 7/16-inch OSB sheathing as tested in accordance with ASTM E1886.

R703.12 Adhered Masonry Veneer Installation

Adhered masonry veneer shall comply with the requirements of Section R703.7.3 and the requirements in Sections 12.1 and 12.3 of TMS 402. Adhered masonry veneer shall be installed in accordance with Section R703.7.1, Article 3.3C of TMS 602 or the manufacturer's instructions.

R703.12.1 Clearances

On exterior stud walls, adhered masonry veneer shall be installed:
  1. Minimum of 4 inches (102 mm) above the earth;
  2. Minimum of 2 inches (51 mm) above paved areas; or
  3. Minimum of 1/2 inch (12.7 mm) above exterior walking surfaces that are supported by the same foundation that supports the exterior wall.

R703.12.2 Flashing at Foundation

A corrosion-resistant screed or flashing of a minimum 0.019-inch (0.48 mm) or 26-gage galvanized or plastic with a minimum vertical attachment flange of 31/2 inches (89 mm) shall be installed to extend a minimum of 1 inch (25 mm) below the foundation plate line on exterior stud walls in accordance with Section R703.4.

R703.12.3 Water-Resistive Barrier

A water-resistive barrier shall be installed as required by Section R703.2 and shall comply with the requirements of Section R703.7.3. The water-resistive barrier shall lap over the exterior of the attachment flange of the screed or flashing provided in accordance with Section R703.12.2.

R703.13 Insulated Vinyl Siding

Insulated vinyl siding shall be certified and labeled as conforming to the requirements of ASTM D7793 by an approved quality control agency.

R703.13.1 Insulated Vinyl Siding and Accessories

Insulated vinyl siding and accessories shall be installed in accordance with the manufacturer's installation instructions.

R703.14 Polypropylene Siding

Polypropylene siding shall be certified and labeled as conforming to the requirements of ASTM D7254, and those of Section R703.14.2 or Section R703.14.3, by an approved quality control agency.

R703.14.1 Polypropylene Siding and Accessories

Polypropylene siding and accessories shall be installed in accordance with manufacturer's installation instructions.

R703.14.1.1 Installation

Polypropylene siding shall be installed over and attached to wood structural panel sheathing with minimum thickness of 7/16 inch (11.1 mm), or other substrate, composed of wood or wood-based material and fasteners having equivalent withdrawal resistance.

R703.14.1.2 Fastener Requirements

Unless otherwise specified in the approved manufacturer's instructions, nails shall be corrosion resistant, with a minimum 0.120-inch (3 mm) shank and minimum 0.313-inch (8 mm) head diameter. Nails shall be a minimum of 11/4 inches (32 mm) long or as necessary to penetrate sheathing or substrate not less than 3/4 inch (19.1 mm). Where the nail fully penetrates the sheathing or nailable substrate, the end of the fastener shall extend not less than 1/4 inch (6.4 mm) beyond the opposite face of the sheathing or substrate. Staples are not permitted.

R703.14.2 Fire Separation

Polypropylene siding shall not be installed on walls with a fire separation distance of less than 5 feet (1524 mm) and walls closer than 10 feet (3048 mm) to a building on another lot.
Exception: Walls perpendicular to the line used to determine the fire separation distance.

R703.14.3 Flame Spread Index

The certification of the flame spread index shall be accompanied by a test report stating that all portions of the test specimen ahead of the flame front remained in position during the test in accordance with ASTM E84 or UL 723.

R703.15 Cladding Attachment Over Foam Sheathing to Wood Framing

Cladding shall be specified and installed in accordance with Section R703, the cladding manufacturer's approved instructions, including any limitations for use over foam plastic sheathing, or an approved design. In addition, the cladding or furring attachments through foam sheathing to framing shall meet or exceed the minimum fastening requirements of Section R703.15.1, Section R703.15.2, or an approved design for support of cladding weight.
Exceptions:
  1. Where the cladding manufacturer has provided approved installation instructions for application over foam sheathing, those requirements shall apply.
  2. For exterior insulation and finish systems, refer to Section R703.9.
  3. For anchored masonry or stone veneer installed over foam sheathing, refer to Section R703.8.

R703.15.1 Direct Attachment

Where cladding is installed directly over foam sheathing without the use of furring, cladding minimum fastening requirements to support the cladding weight shall be as specified in Table R703.15.1.
TABLE R703.15.1
CLADDING MINIMUM FASTENING REQUIREMENTS FOR DIRECT ATTACHMENT OVER FOAM PLASTIC SHEATHING TO SUPPORT CLADDING WEIGHTa
CLADDING
FASTENER
THROUGH
FOAM
SHEATHING
 CLADDING
FASTENER
TYPE AND
MINIMUM
SIZEb
 CLADDING
FASTENER
VERTICAL
SPACING
(inches)
 MAXIMUM THICKNESS OF FOAM SHEATHINGc
(inches)
16" o.c. Fastener Horizontal Spacing 24" o.c. Fastener Horizontal Spacing
Cladding Weight: Cladding Weight:
3 psf 11 psf 18 psf 25 psf 3 psf 11 psf 18 psf 25 psf
Wood framing
(minimum
11/4-inch
penetration)		 0.113"
nail
 6 2.00 1.45 0.75 DR 2.00 0.85 DR DR
8 2.00 1.00 DR DR 2.00 0.55 DR DR
12 2.00 0.55 DR DR 1.85 DR DR DR
0.120"
nail
 6 3.00 1.70 0.90 0.55 3.00 1.05 0.50 DR
8 3.00 1.20 0.60 DR 3.00 0.70 DR DR
12 3.00 0.70 DR DR 2.15 DR DR DR
0.131"
nail
 6 4.00 2.15 1.20 0.75 4.00 1.35 0.70 DR
8 4.00 1.55 0.80 DR 4.00 0.90 DR DR
12 4.00 0.90 DR DR 2.70 0.50 DR DR
0.162"
nail
 6 4.00 3.55 2.05 1.40 4.00 2.25 1.25 0.80
8 4.00 2.55 1.45 0.95 4.00 1.60 0.85 0.50
12 4.00 1.60 0.85 0.50 4.00 0.95 DR DR
For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
DR = Design Required.
o.c. = On Center.
  1. Wood framing shall be Spruce-pine-fir or any wood species with a specific gravity of 0.42 or greater in accordance with AWC NDS.
  2. Nail fasteners shall comply with ASTM F1667, except nail length shall be permitted to exceed ASTM F1667 standard lengths.
  3. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.

R703.15.2 Furred Cladding Attachment

Where wood furring is used to attach cladding over foam sheathing, furring minimum fastening requirements to support the cladding weight shall be as specified in Table R703.15.2. Where placed horizontally, wood furring shall be preservative-treated wood in accordance with Section R317.1 or naturally durable wood and fasteners shall be corrosion resistant in accordance Section R317.3.
TABLE R703.15.2
FURRING MINIMUM FASTENING REQUIREMENTS FOR APPLICATION OVER FOAM PLASTIC SHEATHING TO SUPPORT CLADDING WEIGHTa, b
FURRING
MATERIAL
FRAMING
MEMBER
FASTENER
TYPE AND

MINIMUM

SIZE
MINIMUM
PENETRATION

INTO WALL

FRAMING

(inches)
FASTENER
SPACING IN

FURRING

(inches)
MAXIMUM THICKNESS OF FOAM SHEATHINGd
(inches)
16" o.c. Furringe24" o.c. Furringe
Siding Weight:Siding Weight:
3 psf11 psf18 psf25 psf3 psf11 psf18 psf25 psf
Minimum
1× wood
furringc
Minimum
2× wood
stud
0.131"
nail
11/484.002.451.450.954.001.600.85DR
124.001.600.85DR4.000.95DRDR
164.001.10DRDR3.050.60DRDR
0.162"
nail
11/484.004.002.451.604.002.751.450.85
124.002.751.450.854.001.650.75DR
164.001.900.95DR4.001.05DRDR
No.10
wood
screw
1124.002.301.200.704.001.400.60DR
164.001.650.75DR4.000.90DRDR
244.000.90DRDR2.85DRDRDR
1/4" lag
screw
11/2124.002.651.500.904.001.650.80DR
164.001.950.950.504.001.10DRDR
244.001.10DRDR3.250.50DRDR
For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
DR = Design Required.
o.c. = On Center.
  1. Wood framing and furring shall be Spruce-pine-fir or any wood species with a specific gravity of 0.42 or greater in accordance with AWC NDS.
  2. Nail fasteners shall comply with ASTM F1667, except nail length shall be permitted to exceed ASTM F1667 standard lengths.
  3. Where the required cladding fastener penetration into wood material exceeds 3/4 inch and is not more than 11/2 inches, a minimum 2× wood furring or an approved design shall be used.
  4. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.
  5. Furring shall be spaced not more than 24 inches on center, in a vertical or horizontal orientation. In a vertical orientation, furring shall be located over wall studs and attached with the required fastener spacing. In a horizontal orientation, the indicated 8-inch and 12-inch fastener spacing in furring shall be achieved by use of two fasteners into studs at 16 inches and 24 inches on center, respectively.

R703.16 Cladding Attachment Over Foam Sheathing to Cold-Formed Steel Framing

Cladding shall be specified and installed in accordance with Section R703, the cladding manufacturer's approved instructions, including any limitations for use over foam plastic sheathing, or an approved design. In addition, the cladding or furring attachments through foam sheathing to framing shall meet or exceed the minimum fastening requirements of Section R703.16.1, Section R703.16.2 or an approved design for support of cladding weight.
Exceptions:
  1. Where the cladding manufacturer has provided approved installation instructions for application over foam sheathing, those requirements shall apply.
  2. For exterior insulation and finish systems, refer to Section R703.9.
  3. For anchored masonry or stone veneer installed over foam sheathing, refer to Section R703.8.

R703.16.1 Direct Attachment

Where cladding is installed directly over foam sheathing without the use of furring, cladding minimum fastening requirements to support the cladding weight shall be as specified in Table R703.16.1.
TABLE R703.16.1
CLADDING MINIMUM FASTENING REQUIREMENTS FOR DIRECT ATTACHMENT OVER FOAM PLASTIC SHEATHING TO SUPPORT CLADDING WEIGHTa
CLADDING FASTENER
THROUGH FOAM
SHEATHING INTO:
 CLADDING FASTENER
TYPE AND MINIMUM
SIZEb
 CLADDING FASTENER
VERTICAL SPACING
(inches)
 MAXIMUM THICKNESS OF FOAM SHEATHINGc
(inches)
16" o.c. Fastener
Horizontal Spacing
 24" o.c. Fastener
Horizontal Spacing
Cladding Weight: Cladding Weight:
3 psf 11 psf 18 psf 25 psf 3 psf 11 psf 18 psf 25 psf
Steel framing
(minimum penetration
of steel thickness + 3
threads)
 No. 8 screw
into 33-mil steel
or thicker
 6 3.00 2.95 2.20 1.45 3.00 2.35 1.25 DR
8 3.00 2.55 1.60 0.60 3.00 1.80 DR DR
12 3.00 1.80 DR DR 3.00 0.65 DR DR
No. 10 screw
into 33-mil steel
 6 4.00 3.50 2.70 1.95 4.00 2.90 1.70 0.55
8 4.00 3.10 2.05 1.00 4.00 2.25 0.70 DR
12 4.00 2.25 0.70 DR 3.70 1.05 DR DR
No. 10 screw
into 43-mil steel
or thicker
 6 4.00 4.00 4.00 3.60 4.00 4.00 3.45 2.70
8 4.00 4.00 3.70 3.00 4.00 3.85 2.80 1.80
12 4.00 3.85 2.80 1.80 4.00 3.05 1.50 DR
For SI: 1 inch = 25.4 mm, 1 mil = 0.0254 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
DR = Design Required.
o.c. = On Center.
  1. Steel framing shall be minimum 33 ksi steel for 33 mil and 43 mil steel, and 50 ksi steel for 54 mil steel or thicker.
  2. Screws shall comply with the requirements of ASTM C1513.
  3. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.

R703.16.2 Furred Cladding Attachment

Where steel or wood furring is used to attach cladding over foam sheathing, furring minimum fastening requirements to support the cladding weight shall be as specified in Table R703.16.2. Where placed horizontally, wood furring shall be preservative-treated wood in accordance with Section R317.1 or naturally durable wood and fasteners shall be corrosion resistant in accordance with Section R317.3. Steel furring shall have a minimum G60 galvanized coating.
TABLE R703.16.2
FURRING MINIMUM FASTENING REQUIREMENTS FOR APPLICATION OVER FOAM PLASTIC SHEATHING TO SUPPORT CLADDING WEIGHTa
FURRING
MATERIAL
 FRAMING
MEMBER
 FASTENER
TYPE AND
MINIMUM
SIZEb
 MINIMUM
PENETRATION
INTO WALL
FRAMING
(inches)
 FASTENER
SPACING IN
FURRING
(inches)
 MAXIMUM THICKNESS OF FOAM SHEATHINGd
(inches)
16" o.c. Furringe 24" o.c. Furringe
Cladding Weight: Cladding Weight:
3 psf 11 psf 18 psf 25 psf 3 psf 11 psf 18 psf 25 psf
Minimum
33-mil steel
furring or
minimum 1×
wood furringc
 33-mil
steel stud
 No. 8
screw
 Steel
thickness + 3
threads
 12 3.00 1.80 DR DR 3.00 0.65 DR DR
16 3.00 1.00 DR DR 2.85 DR DR DR
24 2.85 DR DR DR 2.20 DR DR DR
No. 10
screw
 Steel
thickness + 3
threads
 12 4.00 2.25 0.70 DR 3.70 1.05 DR DR
16 3.85 1.45 DR DR 3.40 DR DR DR
24 3.40 DR DR DR 2.70 DR DR DR
43-mil
or thicker
steel stud		 No. 8
Screw
 Steel
thickness + 3
threads
 12 3.00 1.80 DR DR 3.00 0.65 DR DR
16 3.00 1.00 DR DR 2.85 DR DR DR
24 2.85 DR DR DR 2.20 DR DR DR
No. 10
screw
 Steel
thickness + 3
threads
 12 4.00 3.85 2.80 1.80 4.00 3.05 1.50 DR
16 4.00 3.30 1.95 0.60 4.00 2.25 DR DR
24 4.00 2.25 DR DR 4.00 0.65 DR DR
For SI: 1 inch = 25.4 mm, 1 mil = 0.0254 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
DR = Design Required.
o.c. = On Center.
  1. Wood furring shall be Spruce-pine-fir or any softwood species with a specific gravity of 0.42 or greater. Steel furring shall be minimum 33-ksi steel. Steel studs shall be minimum 33-ksi steel for 33-mil and 43-mil thickness, and 50-ksi steel for 54-mil steel or thicker.
  2. Screws shall comply with the requirements of ASTM C1513.
  3. Where the required cladding fastener penetration into wood material exceeds 3/4 inch and is not more than 11/2 inches, a minimum 2-inch nominal wood furring or an approved design shall be used.
  4. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.
  5. Furring shall be spaced not more than 24 inches (610 mm) on center, in a vertical or horizontal orientation. In a vertical orientation, furring shall be located over wall studs and attached with the required fastener spacing. In a horizontal orientation, the indicated 8-inch and 12-inch fastener spacing in furring shall be achieved by use of two fasteners into studs at 16 inches and 24 inches on center, respectively.

R703.17 Cladding Attachment Over Foam Sheathing to Masonry or Concrete Wall Construction

Cladding shall be specified and installed in accordance with Section 703.3 and the cladding manufacturer's instructions or an approved design. Foam sheathing shall be attached to masonry or concrete construction in accordance with the insulation manufacturer's installation instructions or an approved design. Furring and furring attachments through foam sheathing into concrete or masonry substrate shall be designed to resist design loads determined in accordance with Section R301, including support of cladding weight as applicable. Fasteners used to attach cladding or furring through foam sheathing to masonry or concrete substrates shall be approved for application into masonry or concrete material and shall be installed in accordance with the fastener manufacturer's instructions.
Exceptions:
  1. Where the cladding manufacturer has provided approved installation instructions for application over foam sheathing and connection to a masonry or concrete substrate, those requirements shall apply.
  2. For exterior insulation and finish systems, refer to Section R703.9.
  3. For anchored masonry or stone veneer installed over foam sheathing, refer to Section R703.8.