CODES

ADOPTS WITH AMENDMENTS:

International Building Code 2012 (IBC 2012)

Copyright

Preface

Effective Use of the International Building Code

Legislation

Chapter 1 Scope and Administration

Chapter 1 Scope and Administration

Chapter 2 Definitions

Chapter 3 Use and Occupancy Classification

Chapter 4 Special Detailed Requirements Based on Use and Occupancy

Chapter 5 General Building Heights and Areas

Chapter 6 Types of Construction

Chapter 7 Fire and Smoke Protection Features

Chapter 8 Interior Finishes

Chapter 9 Fire Protection Systems

Chapter 10 Means of Egress

Chapter 11 Accessibility

Chapter 12 Interior Environment

Chapter 13 Energy Efficiency

Chapter 14 Exterior Walls

Chapter 15 Roof Assemblies and Rooftop Structures

Chapter 16 Structural Design

Chapter 17 Special Inspections and Tests

Chapter 18 Soils and Foundations

Chapter 19 Concrete

Chapter 20 Aluminum

Chapter 21 Masonry

Chapter 22 Steel

Chapter 23 Wood

Chapter 24 Glass and Glazing

Chapter 25 Gypsum Board and Plaster

Chapter 26 Plastic

Chapter 27 Electrical

Chapter 28 Mechanical Systems

Chapter 29 Plumbing Systems

Chapter 30 Elevators and Conveying Systems

Chapter 31 Special Construction

Chapter 32 Encroachments Into the Public Right-Of-Way

Chapter 33 Safeguards During Construction

Chapter 34 Existing Buildings and Structures

Chapter 35 Referenced Standards

Appendix A Employee Qualifications

Appendix B Board of Appeals

Appendix C GROUP U—AGRICULTURAL BUILDINGS

Appendix D Fire Districts

Appendix E Supplementary Accessibility Requirements

Appendix F Rodentproofing

Appendix G Flood-Resistant Construction

Appendix H Signs

Appendix I Patio Covers

Appendix J Grading

Appendix K Administrative Provisions

Appendix L Earthquake Recording Instrumentation

Appendix M Tsunami-Generated Flood Hazard

Provisions of this chapter shall govern the materials, design, construction and quality of gypsum board, lath, gypsum plaster and cement plaster.
Lathing, plastering and gypsum board construction shall be done in the manner and with the materials specified in this chapter, and when required for fire protection, shall also comply with the provisions of Chapter 7.
Other approved wall or ceiling coverings shall be permitted to be installed in accordance with the recommendations of the manufacturer and the conditions of approval.
The following terms are defined in Chapter 2:
CEMENT PLASTER.
EXTERIOR SURFACES.
GYPSUM BOARD.
GYPSUM PLASTER.
GYPSUM VENEER PLASTER.
INTERIOR SURFACES.
WEATHER-EXPOSED SURFACES.
WIRE BACKING.
Lath and gypsum board shall be inspected in accordance with Section 110.3.5.
The following requirements shall be met where construction involves gypsum board, lath and plaster in vertical and horizontal assemblies.
Wood supports for lath or gypsum board, as well as wood stripping or furring, shall not be less than 2 inches (51 mm) nominal thickness in the least dimension.

Exception: The minimum nominal dimension of wood furring strips installed over solid backing shall not be less than 1 inch by 2 inches (25 mm by 51 mm).

The minimum thickness of vertically erected studless solid plaster partitions of 3/8-inch (9.5 mm) and 3/4-inch (19.1 mm) rib metal lath or 1/2-inch thick (12.7 mm) long-length gypsum lath and gypsum board partitions shall be 2 inches (51 mm).
Wood-framed shear walls sheathed with gypsum board, lath and plaster shall be designed and constructed in accordance with Section 2306.3 and are permitted to resist wind and seismic loads. Walls resisting seismic loads shall be subject to the limitations in Section 12.2.1 of ASCE 7.
Cold-formed steel-framed shear walls sheathed with gypsum board and constructed in accordance with the materials and provisions of Section 2211.6 are permitted to resist wind and seismic loads. Walls resisting seismic loads shall be subject to the limitations in Section 12.2.1 of ASCE 7.
Gypsum board materials and accessories shall be identified by the manufacturer's designation to indicate compliance with the appropriate standards referenced in this section and stored to protect such materials from the weather.
Gypsum board materials shall conform to the appropriate standards listed in Table 2506.2 and Chapter 35 and, where required for fire protection, shall conform to the provisions of Chapter 7.

TABLE 2506.2
GYPSUM BOARD MATERIALS AND ACCESSORIES

MATERIALSTANDARD
Accessories for gypsum boardASTM C 1047
Adhesives for fastening gypsum wallboardASTM C 557
Elastomeric joint sealantsASTM C 920
Fiber-reinforced gypsum panelsASTM C 1278
Glass mat gypsum backing panelASTM C 1178
Glass mat gypsum panelASTM C 1658
Glass mat gypsum substrateASTM C 1177
Joint reinforcing tape and compoundASTM C 474; C 475
Nails FOR gypsum boardsASTM C 514,
F 547, F 1667
Steel screwsASTM C 954; C 1002
Steel studs, load-bearingASTM C 955
Steel studs, nonload-bearingASTM C 645
Standard specification for gypsum boardASTM C 1396
Testing gypsum and gypsum productsASTM C 22; C 472;
C 473
Metal suspension systems for acoustical and lay-in panel ceilings shall conform with ASTM C 635 listed in Chapter 35 and Section 13.5.6 of ASCE 7 for installation in high seismic areas.
Lathing and plastering materials and accessories shall be marked by the manufacturer’s designation to indicate compliance with the appropriate standards referenced in this section and stored in such a manner to protect them from the weather.
Lathing and plastering materials shall conform to the standards listed in Table 2507.2 and Chapter 35 and, where required for fire protection, shall also conform to the provisions of Chapter 7.

TABLE 2507.2
LATH, PLASTERING MATERIALS AND ACCESSORIES

MATERIALSTANDARD
Accessories for gypsum veneer baseASTM C 1047
Blended cementASTM C 595
Exterior plaster bonding compoundsASTM C 932
Gypsum casting and molding plasterASTM C 59
Gypsum Keene''s cementASTM C 61
Gypsum plasterASTM C 28
Gypsum veneer plasterASTM C 587
Interior bonding compounds, gypsumASTM C 631
Lime plastersASTM C 5; C 206
Masonry cementASTM C 91
Metal lathASTM C 847
Plaster aggregates
Sand
Perlite
Vermiculite

ASTM C 35; C 897
ASTM C 35
ASTM C 35
Plastic cementASTM C 1328
Portland cementASTM C 150
Steel screwsASTM C 1002; C 954
Steel studs and trackASTM C 645; C 955
Welded wire lathASTM C 933
Woven wire plaster baseASTM C 1032
Gypsum board and gypsum plaster construction shall be of the materials listed in Tables 2506.2 and 2507.2. These materials shall be assembled and installed in compliance with the appropriate standards listed in Tables 2508.1 and 2511.1.1, and Chapter 35.

TABLE 2508.1
INSTALLATION OF GYPSUM CONSTRUCTION

MATERIALSTANDARD
Gypsum boardGA-216; ASTM C 840
Gypsum sheathingASTM C 1280
Gypsum veneer baseASTM C 844
Interior lathing and furringASTM C 841
Steel framing for gypsum boardsASTM C 754; C 1007
Gypsum wallboard or gypsum plaster shall not be used in any exterior surface where such gypsum construction will be exposed directly to the weather. Gypsum wallboard shall not be used where there will be direct exposure to water or continuous high humidity conditions. Gypsum sheathing shall be installed on exterior surfaces in accordance with ASTM C 1280.
Gypsum wallboard, gypsum lath or gypsum plaster shall not be installed until weather protection for the installation is provided.
Edges and ends of gypsum board shall occur on the framing members, except those edges and ends that are perpendicular to the framing members. Edges and ends of gypsum board shall be in moderate contact except in concealed spaces where fire-resistancerated construction, shear resistance or diaphragm action is not required.
Fasteners at the top and bottom plates of vertical assemblies, or the edges and ends of horizontal assemblies perpendicular to supports, and at the wall line are permitted to be omitted except on shear resisting elements or fire-resistance-rated assemblies. Fasteners shall be applied in such a manner as not to fracture the face paper with the fastener head.
Gypsum board fire-resistance-rated assemblies shall have joints and fasteners treated.
Exception: Joint and fastener treatment need not be provided where any of the following conditions occur:
1. Where the gypsum board is to receive a decorative finish such as wood paneling, battens, acoustical finishes or any similar application that would be equivalent to joint treatment.
2. On single-layer systems where joints occur over wood framing members.
3. Square edge or tongue-and-groove edge gypsum board (V-edge), gypsum backing board or gypsum sheathing.
4. On multilayer systems where the joints of adjacent layers are offset from one to another.
5. Assemblies tested without joint treatment.
Gypsum board shall be permitted to be used on wood joists to create a horizontal diaphragm ceiling in accordance with Table 2508.5.

TABLE 2508.5
SHEAR CAPACITY FOR HORIZONTAL WOOD FRAMED GYPSUM BOARD DIAPHRAGM CEILING ASSEMBLIES

MATERIALTHICKNESS OF MATERIAL
(MINIMUM) (inches)
SPACING OF FRAMING
MEMBERS (MAXIMUM)
(inches)
SHEAR VALUEa, b
(plf of ceiling)
MIMIMUM FASTENER SIZE
Gypsum board1/216 o.c.905d cooler or wallboard nail;
15/8-inch long; 0.086-inch shank;
15/64-inch headc
Gypsum board1/224 o.c.705d cooler or wallboard nail;
15/8-inch long; 0.086-inch shank;
15/64-inch headc
For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.59 N/m.
a. Values are not cumulative with other horizontal diaphragm values and are for short-term loading due to wind or seismic loading. Values shall be reduced 25 percent for normal loading.
b. Values shall be reduced 50 percent in Seismic Design Categories D, E and F.
c. 11/4-inch, No. 6 Type S or W screws are permitted to be substituted for the listed nails.
The maximum allowable diaphragm proportions shall be 11/2:1 between shear resisting elements. Rotation or cantilever conditions shall not be permitted.
Gypsum board used in a horizontal diaphragm ceiling shall be installed perpendicular to ceiling framing members. End joints of adjacent courses of gypsum board shall not occur on the same joist.
All perimeter edges shall be blocked using a wood member not less than 2-inch by 6-inch (51 mm by 159 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.
Fasteners used for the attachment of gypsum board to a horizontal diaphragm ceiling shall be as defined in Table 2508.5. Fasteners shall be spaced not more than 7 inches (178 mm) on center (o.c.) at all supports, including perimeter blocking, and not more than 3/8 inch (9.5 mm) from the edges and ends of the gypsum board.
Gypsum board shall not be used in diaphragm ceilings to resist lateral forces imposed by masonry or concrete construction.
Showers and public toilet walls shall conform to Section 1210.2.
Glass mat water-resistant gypsum backing panels, discrete nonasbestos fiber-cement interior substrate sheets or nonasbestos fiber-mat reinforced cementitious backer units in compliance with ASTM C 1178, C 1288 or C 1325 and installed in accordance with manufacturer recommendations shall be used as a base for wall tile in tub and shower areas and wall and ceiling panels in shower areas. Water-resistant gypsum backing board shall be used as a base for tile in water closet compartment walls when installed in accordance with GA-216 or ASTM C 840 and manufacturer recommendations. Regular gypsum wallboard is permitted under tile or wall panels in other wall and ceiling areas when installed in accordance with GA-216 or ASTM C 840.
Water-resistant gypsum backing board shall not be used in the following locations:
1. Over a vapor retarder in shower or bathtub compartments.
2. Where there will be direct exposure to water or in areas subject to continuous high humidity.
3. On ceilings where frame spacing exceeds 12 inches (305 mm) o.c. for 1/2-inch thick (12.7 mm) water-resistant gypsum backing board and more than 16 inches (406 mm) o.c. for 5/8-inch thick (15.9 mm) water-resistant gypsum backing board.
Exterior and interior cement plaster and lathing shall be done with the appropriate materials listed in Table 2507.2 and Chapter 35.
Materials shall be stored in such a manner as to protect such materials from the weather.
Installation of these materials shall be in compliance with ASTM C 926 and ASTM C 1063.
Metal lath and lath attachments shall be of corrosion-resistant material.
Backing or a lath shall provide sufficient rigidity to permit plaster applications.
Where lath on vertical surfaces extends between rafters or other similar projecting members, solid backing shall be installed to provide support for lath and attachments.
Gypsum lath or gypsum wallboard shall not be used as a backing for cement plaster.

Exception: Gypsum lath or gypsum wallboard is permitted, with a water-resistive barrier, as a backing for self-furred metal lath or self-furred wire fabric lath and cement plaster where either of the following conditions occur:

1. On horizontal supports of ceilings or roof soffits.
2. On interior walls.
Gypsum sheathing is permitted as a backing for metal or wire fabric lath and cement plaster on walls. A water-resistive barrier shall be provided in accordance with Section 2510.6.
Wire backing is not required under expanded metal lath or paperbacked wire fabric lath.
Water-resistive barriers shall be installed as required in Section 1404.2 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 1405.4) 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 drainage space.
Surfaces shall be clean, free from efflorescence, sufficiently damp and rough for proper bond. If the surface is insufficiently rough, approved bonding agents or a Portland cement dash bond coat mixed in proportions of not more than two parts volume of sand to one part volume of Portland cement or plastic cement shall be applied. The dash bond coat shall be left undisturbed and shall be moist cured not less than 24 hours.
Plastering gypsum plaster or cement plaster shall not be less than three coats where applied over metal lath or wire fabric lath and not less than two coats where applied over other bases permitted by this chapter.
Exception: Gypsum veneer plaster and cement plaster specifically designed and approved for one-coat applications.
Installation of lathing and plaster materials shall conform with Table 2511.1.1 and Section 2507.

TABLE 2511.1.1
INSTALLATION OF PLASTER CONSTRUCTION

MATERIALSTANDARD
Cement plasterASTM C 926
Gypsum plasterASTM C 842
Gypsum veneer plasterASTM C 843
Interior lathing and furring
(gypsum plaster)
ASTM C 841
Lathing and furring (cement plaster)ASTM C 1063
Steel framingASTM C 754; C 1007
Plaster shall not be applied directly to fiber insulation board. Cement plaster shall not be applied directly to gypsum lath or gypsum plaster except as specified in Sections 2510.5.1 and 2510.5.2.
Where installed, grounds shall ensure the minimum thickness of plaster as set forth in ASTM C 842 and ASTM C 926. Plaster thickness shall be measured from the face of lath and other bases.
Condition of surfaces shall be as specified in Section 2510.7. Approved specially prepared gypsum plaster designed for application to concrete surfaces or approved acoustical plaster is permitted. The total thickness of base coat plaster applied to concrete ceilings shall be as set forth in ASTM C 842 or ASTM C 926. Should ceiling surfaces require more than the maximum thickness permitted in ASTM C 842 or ASTM C 926, metal lath or wire fabric lath shall be installed on such surfaces before plastering.
Showers and public toilet walls shall conform to Sections 1210.2 and 1210.3. When wood frame walls and partitions are covered on the interior with cement plaster or tile of similar material and are subject to water splash, the framing shall be protected with an approved moisture barrier.
Plastering with cement plaster shall be not less than three coats when applied over metal lath or wire fabric lath or gypsum board backing as specified in Section 2510.5 and shall be not less than two coats when applied over masonry or concrete. If the plaster surface is to be completely covered by veneer or other facing material, or is completely concealed by another wall, plaster application need only be two coats, provided the total thickness is as set forth in ASTM C 926.
On wood framed or steel stud construction with an on-grade concrete floor slab system, exterior plaster shall be applied in such a manner as to cover, but not to extend below, the lath and paper. The application of lath, paper and flashing or drip screeds shall comply with ASTM C 1063.
A minimum 0.019-inch (0.48 mm) (No. 26 galvanized sheet gage), corrosion-resistant 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 C 926. The weep screed shall be placed a minimum of 4 inches (102 mm) above the earth or 2 inches (51 mm) above paved areas and be of a type that will allow trapped water to drain to the exterior of the building. The water-resistive barrier shall lap the attachment flange. The exterior lath shall cover and terminate on the attachment flange of the weep screed.
Only approved plasticity agents and approved amounts thereof shall be added to Portland cement or blended cements. When plastic cement or masonry cement is used, no additional lime or plasticizers shall be added. Hydrated lime or the equivalent amount of lime putty used as a plasticizer is permitted to be added to cement plaster or cement and lime plaster in an amount not to exceed that set forth in ASTM C 926.
Gypsum plaster shall not be used on exterior surfaces.
Plaster coats shall be protected from freezing for a period of not less than 24 hours after set has occurred. Plaster shall be applied when the ambient temperature is higher than 40°F (4°C), unless provisions are made to keep cement plaster work above 40°F (4°C) during application and 48 hours thereafter.
The second coat shall be brought out to proper thickness, rodded and floated sufficiently rough to provide adequate bond for the finish coat. The second coat shall have no variation greater than 1/4 inch (6.4 mm) in any direction under a 5-foot (1524 mm) straight edge.
First and second coats of cement plaster shall be applied and moist cured as set forth in ASTM C 926 and Table 2512.6.

TABLE 2512.6
CEMENT PLASTERS

COATMINIMUM PERIOD
MOIST CURING
MINIMUM INTERVAL
BETWEEN COATS
First48 hoursa48 hoursb
Second48 hours7 daysc
FinishNote c
a. The first two coats shall be as required for the first coats of exterior plaster, except that the moist-curing time period between the first and second coats shall not be less than 24 hours. Moist curing shall not be required where job and weather conditions are favorable to the retention of moisture in the cement plaster for the required time period.
b. Twenty-four-hour minimum interval between coats of interior cement plaster. For alternative method of application, see Section 2512.8.
c. Finish coat plaster is permitted to be applied to interior cement plaster base coats after a 48-hour period.
Where applied over gypsum backing as specified in Section 2510.5 or directly to unit masonry surfaces, the second coat is permitted to be applied as soon as the first coat has attained sufficient hardness.
The second coat is permitted to be applied as soon as the first coat has attained sufficient rigidity to receive the second coat.
When using this method of application, calcium aluminate cement up to 15 percent of the weight of the Portland cement is permitted to be added to the mix.
Curing of the first coat is permitted to be omitted and the second coat shall be cured as set forth in ASTM C 926 and Table 2512.6.
Cement plaster finish coats shall be applied over base coats that have been in place for the time periods set forth in ASTM C 926. The third or finish coat shall be applied with sufficient material and pressure to bond and to cover the brown coat and shall be of sufficient thickness to conceal the brown coat.
Exposed natural or integrally colored aggregate is permitted to be partially embedded in a natural or colored bedding coat of cement plaster or gypsum plaster, subject to the provisions of this section.
The aggregate shall be applied manually or mechanically and shall consist of marble chips, pebbles or similar durable, moderately hard (three or more on the Mohs hardness scale), nonreactive materials.
The bedding coat for interior or exterior surfaces shall be composed of one part Portland cement and one part Type S lime; or one part blended cement and one part Type S lime; or masonry cement; or plastic cement, and a maximum of three parts of graded white or natural sand by volume. The bedding coat for interior surfaces shall be composed of 100 pounds (45.4 kg) of neat gypsum plaster and a maximum of 200 pounds (90.8 kg) of graded white sand. A factory-prepared bedding coat for interior or exterior use is permitted. The bedding coat for exterior surfaces shall have a minimum compressive strength of 1,000 pounds per square inch (psi) (6895 kPa).
The bedding coat is permitted to be applied directly over the first (scratch) coat of plaster, provided the ultimate overall thickness is a minimum of 7/8 inch (22 mm), including lath. Over concrete or masonry surfaces, the overall thickness shall be a minimum of 1/2 inch (12.7 mm).
Exposed aggregate plaster is permitted to be applied over concrete, masonry, cement plaster base coats or gypsum plaster base coats installed in accordance with Section 2511 or 2512.
Masonry and concrete surfaces shall be prepared in accordance with the provisions of Section 2510.7.
Cement plaster base coats shall be cured in accordance with ASTM C 926. Cement plaster bedding coats shall retain sufficient moisture for hydration (hardening) for 24 hours minimum or, where necessary, shall be kept damp for 24 hours by light water spraying.
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