CBC · California Building Code

How must flashing be provided at wall openings, transitions and veneer terminations?

Flashing is required at all window/door perimeters, penetrations, roof or projection intersections, and at veneer supports/terminations to keep water out or move it to the exterior; adhered veneer requires a corrosion‑resistant screed (min. 0.019 in / 26 ga) with a 3½‑inch flange and the WRB lapped over that flange.

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Last reviewed: July 5, 2026

What the code requires — 2–4 sentences

Flashing must be installed to prevent moisture entry into exterior walls or to redirect moisture to the exterior or to a compliant water‑resistive barrier; it is required at the perimeters of windows and doors, at penetrations and terminations of wall assemblies, at wall/roof or wall/projection intersections, and at veneer support points and terminations. These general requirements are stated in § 1404.4 of the CBC. Specific prescriptions for exterior adhered masonry veneer (screed, flashing gauge/flange and clearances) are in § 1404.11.1.

Requirements in detail

Purpose and scope

The flashing objective is moisture control: either keep water out of the exterior wall or collect and redirect it to the exterior or to the water‑resistive barrier (WRB) and drainage system required by § 1403.2 and § 1402.2. See § 1404.4.

Where flashing is required

Perimeters of exterior door and window assemblies (see § 1404.4.1 for acceptable detailing approaches).
Penetrations and terminations of exterior wall assemblies.
Intersections of exterior walls with roofs, chimneys, porches, decks, balconies and similar projections.
Built‑in gutters and other locations where moisture could enter the wall.
In anchored masonry veneer (designed per § 1404.7), flashing and weep holes located at specified heights above grade and at points of support (shelf angles, lintels). See § 1404.4.3.
For exterior adhered masonry veneer, a corrosion‑resistant screed/flash at the foundation is required with specific gauge and flange dimensions; WRB must lap over the screed flange. See § 1404.11.1.2 and § 1404.11.1.2.1.

How fenestration flashing must be shown or installed

Flashing of fenestration to the wall assembly must follow the fenestration manufacturer's instructions, or when those do not apply, follow one of: the WRB manufacturer’s flashing instructions, the flashing manufacturer’s instructions, a registered design professional’s design, or other approved methods. See § 1404.4.1.

Materials and performance notes

Self‑adhered membrane flashings used for fenestration must comply with AAMA 711; fluid‑applied membrane flashings must comply with AAMA 714. See § 1404.4.
For exterior adhered masonry veneer: screed/flash must be corrosion‑resistant, minimum 0.019‑inch (0.48 mm) (26 gauge) galvanized metal or plastic; vertical attachment flange minimum 3 1/2 in (89 mm); installed to extend not less than 1 in (25 mm) below the foundation plate line on exterior stud walls; WRB shall lap over the exterior of the flange. See § 1404.11.1.2.1.

Decision-relevant dimensions / values

Requirement	Value / dimension	Where to apply	Code Reference
Minimum flashing gauge for exterior adhered veneer screed	0.019 in (0.48 mm) / 26 ga (galvanized) or plastic	Screed/flashing at foundation for exterior adhered masonry veneer	§ 1404.11.1.2.1
Minimum vertical attachment flange (screed)	3 1/2 in (89 mm)	Screed/flashing vertical attachment on exterior stud walls	§ 1404.11.1.2.1
Screed extension below foundation plate line	≥ 1 in (25 mm)	Screed/flashing on exterior stud walls	§ 1404.11.1.2.1
Masonry veneer flashing height above finished ground	≤ 10 in (245 mm) above finished ground for anchored veneer	Anchored veneer flashing and weep holes location above foundation	§ 1404.4.3
Fenestration flashing method acceptance	Manufacturer’s instructions or approved alternate (WRB mfr, flashing mfr, RDP design, or other)	Window/door perimeter flashing	§ 1404.4.1
Self‑adhered / fluid applied flashing standards	AAMA 711 (self‑adhered), AAMA 714 (fluid applied)	Flashings used at fenestration / openings	§ 1404.4
Clearances for exterior adhered masonry veneer	≥ 4 in above earth; ≥ 2 in above paved areas; ≥ 1/2 in above supported walking surfaces	Veneer clearance to grade/walkways	§ 1404.11.1.3

(Use these numeric values directly in shop drawings and details; if a manufacturer or an RDP specifies alternate dimensions, provide the manufacturer/RDP documentation to the building official per § 1404.4.1.)

Exceptions & special cases

The CBC allows fenestration flashing to be installed per the fenestration manufacturer's instructions; where those instructions do not address the condition, other listed alternatives are acceptable (WRB maker instructions, flashing maker instructions, RDP design, or approved methods). See § 1404.4.1.
The CBC requires adhered masonry veneer to follow § 1404.11 and the manufacturer’s instructions; the code references additional WRB requirements in § 2510.6 for adhered veneer WRB — the full text of § 2510.6 was not included in the retrieved files, so consult that section for the WRB specifics. § 1404.11.1.1 references § 2510.6.
Anchored masonry veneer flashing locations are tied to the design in § 1404.7; anchored veneer specifics (support, ties, airspace) must be coordinated with that section. The retrieved excerpt references anchored veneer designed per § 1404.7 for the flashing/weeps location.

If a wall assembly has been demonstrated by ASTM E331 testing to resist wind‑driven rain (with representative openings, joints and intersections), some drainage/flashing requirements may not apply — see related provisions (ASTM test conditions) in § 1402.2; check that section when relying on tested assemblies.

Common mistakes

Not lapping the WRB over the screed/flashing flange (WRB must lap over the exterior of the attachment flange for adhered veneer screeds per § 1404.11.1.2.1).
Using metal thinner than the required minimum gauge or non‑corrosion‑resistant material for the screed/flash where code prescribes 0.019 in / 26 ga minimum. § 1404.11.1.2.1.
Omitting flashing at penetrations, perimeters of fenestration, and at support points (lintels, shelf angles). § 1404.4 requires flashing at these locations.
Installing flashing that is not continuous where code expects continuity (for example, continuous flashing under sills, and continuously above projecting trim). § 1404.4.
Relying on a generic detail instead of following the fenestration manufacturer’s flashing instructions (or one of the acceptable alternatives) per § 1404.4.1.

Worked example — concrete scenario with numbers

Scenario: A contractor is installing exterior adhered brick veneer over a wood stud wall on a house foundation. The design calls for adhered masonry veneer at ground level.

How to detail the bottom termination and WRB per the CBC excerpts:

Provide a corrosion‑resistant screed/flash at the foundation of minimum 0.019 in (26 ga) galvanized metal (or approved plastic). This matches § 1404.11.1.2.1.
Fabricate the screed with a vertical attachment flange ≥ 3 1/2 in (89 mm) high, attached at the stud wall. The WRB is installed behind the veneer and is lapped over the exterior face of that flange (WRB over flange), per § 1404.11.1.2.1.
Extend the screed so it projects at least 1 in (25 mm) below the foundation plate line. This ensures the code minimum extension into the cavity and is specified in § 1404.11.1.2.1.
Keep the finished veneer face at least 4 in (102 mm) above earth grade (or 2 in above paved areas), per clearances in § 1404.11.1.3.
At any shelf angle or lintel supporting veneer above an opening, install flashing and weep holes in the first course of masonry above the support; for anchored veneer the flashing/weep placement near grade must not be more than 10 in (245 mm) above finished ground level as required by § 1404.4.3.
For window perimeters, follow the window manufacturer’s flashing instructions; if the manufacturer doesn’t address a condition, use the WRB manufacturer’s instructions or provide a registered design professional’s flashing design per § 1404.4.1.

This set of numbers and steps is directly tied to the code text cited above and should be shown on the plan elevation and detail sheets so the building official can verify compliance.

Related provisions (CBC sections)

§ 1404.4 — Flashing: scope, locations required, material standards (AAMA 711 / 714) and fenestration instruction hierarchy.
§ 1404.4.1 — Fenestration flashing: acceptable sources for flashing instructions (manufacturer, WRB mfr, flashing mfr, RDP, other).
§ 1404.4.3 — Masonry: location of flashing and weep holes for anchored veneer (height relative to finished grade and supports).
§ 1404.11.1 — Exterior adhered masonry veneer: general installation requirement and cross‑references to WRB and flashing rules.
§ 1404.11.1.2.1 — Flashing at foundation: screed gauge, flange height, and required lap of WRB over flange.
§ 1403.2 — Water‑resistive barrier (WRB) — the flashing requirements are intended to work with the WRB and means of drainage required by § 1403.2; consult § 1403.2 for WRB requirements.
§ 1402.2 — Weather protection and the requirement for an exterior wall assembly with WRB and means of drainage (context for flashing performance).

Code references

Grounded in the retrieved California Building Code — click a citation to read the verbatim passage:

CBC § 1404.3.1 High relevance — show source text
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EXTERIOR WALLS

1404.3.1 Spray foam plastic insulation for moisture control with Class II and III vapor retarders. For purposes of compliance with Tables 1404.3(3) and 1404.3(4), spray foam with a maximum permeance of 1.5 perms at the installed thickness applied to the interior side of wood structural panels, fiberboard, insulating sheathing or gypsum shall be deemed to meet the continuous insulation moisture control requirement in accordance with one of the following conditions:
1. The spray foam R -value meets or exceeds the specified continuous insulation R-value.
2. The combined R -value of the spray foam and continuous insulation is equal to or greater than the specified continuous insulation R -value.
1404.3.2 Vapor retarder installation. Vapor retarders shall be installed in accordance with the manufacturer’s instructions or an approved design. Where a vapor retarder also functions as a component of a continuous air barrier, the vapor retarder shall be installed as an air barrier in accordance with the California Energy Code . 1404.3.3 California Energy Code and International Energy Conservation Code Climate Zones. The IECC climate zones used by this section differ from those used by the California Energy Code to determine applicability of energy efficiency measures. Comparison of IECC and California Energy Code climate zones is shown in Chapter 12, Table 1202.3.1. 1404.4 Flashing. Flashing shall be installed in such a manner so as to prevent moisture from entering the exterior wall or to redirect that moisture to the surface of the exterior wall covering or to a water-resistive barrier complying with Section 1403.2 and that is part of a means of drainage complying with Section 1402.2. Flashing shall be installed at the perimeters of exterior door and window assemblies in accordance with Section 1404.4.1, penetrations and terminations of exterior wall assemblies, exterior wall intersections with roofs, chimneys, porches, decks, balconies and similar projections and at built-in gutters and similar locations where moisture could enter the wall. Flashing with projecting flanges shall be installed on both sides and the ends of copings, under sills and continuously above projecting trim. Where self-adhered membranes are used as flashings of fenestration in exterior wall assemblies, those self-adhered flashings shall comply with AAMA 711. Where fluid applied membranes are used as flashing for exterior wall openings, those fluid applied membrane flashings shall comply with AAMA 714. 1404.4.1 Fenestration flashing. Flashing of the fenestration to the wall assembly shall comply with the fenestration manufacturer’s instructions or, for conditions not addressed by the fenestration manufacturer’s instructions, shall comply with one of the following:
1. The water-resistive barrier manufacturer’s flashing instructions.
2. The flashing manufacturer’s flashing instructions.
3. A flashing design or method of a registered design professional.
4. Other approved methods. 1404.4.2 Exterior wall pockets. In exterior walls of buildings or structures, wall pockets or crevices in which moisture can accumulate shall be avoided or protected with caps or drips, or other approved means shall be provided to prevent water damage.
CBC § 1403.2 High relevance — show source text
** Flashing shall be installed in such a manner so as to prevent moisture from entering the exterior wall or to redirect that moisture to the surface of the exterior wall covering or to a water-resistive barrier complying with Section 1403.2 and that is part of a means of drainage complying with Section 1402.2. Flashing shall be installed at the perimeters of exterior door and window assemblies in accordance with Section 1404.4.1, penetrations and terminations of exterior wall assemblies, exterior wall intersections with roofs, chimneys, porches, decks, balconies and similar projections and at built-in gutters and similar locations where moisture could enter the wall. Flashing with projecting flanges shall be installed on both sides and the ends of copings, under sills and continuously above projecting trim. Where self-adhered membranes are used as flashings of fenestration in exterior wall assemblies, those self-adhered flashings shall comply with AAMA 711. Where fluid applied membranes are used as flashing for exterior wall openings, those fluid applied membrane flashings shall comply with AAMA 714. 1404.4.1 Fenestration flashing. Flashing of the fenestration to the wall assembly shall comply with the fenestration manufacturer’s instructions or, for conditions not addressed by the fenestration manufacturer’s instructions, shall comply with one of the following:
1. The water-resistive barrier manufacturer’s flashing instructions.
2. The flashing manufacturer’s flashing instructions.
3. A flashing design or method of a registered design professional.
4. Other approved methods. 1404.4.2 Exterior wall pockets. In exterior walls of buildings or structures, wall pockets or crevices in which moisture can accumulate shall be avoided or protected with caps or drips, or other approved means shall be provided to prevent water damage.
1404.4.3 Masonry. Flashing and weep holes in anchored veneer designed in accordance with Section 1404.7 shall be located not more than 10 inches (245 mm) above finished ground level above the foundation wall or slab. At other points of support including structural floors, shelf angles and lintels, flashing and weep holes shall be located in the first course of masonry above the support.

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EXTERIOR WALLS

[BS] 1404.5 Fastening. Exterior wall coverings shall be securely fastened with corrosion-resistant fasteners in accordance with this code or the approved manufacturer’s instructions. Fastening of claddings or furring through foam plastic insulating sheathing shall comply with Section 1404.5.1, 1404.5.2 or 1404.5.3, as applicable.

[BS] 1404.5.1 Cladding attachment over foam sheathing to masonry or concrete wall construction. Cladding shall be specified and installed in accordance with this chapter and the cladding manufacturer’s installation 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 shall be designed to resist design loads determined in accordance with Chapter 16, 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 installation instructions.
CBC § 0.0162 High relevance — show source text
per square foot| |Lead-coated high-yield copper|0.0162 nominal|—|ASTM B101, 12 oz. per square foot| |Painted terne|—|—|20| |Stainless steel|—|28|—| |Zinc alloy|0.027|—|—| |For SI: 1 inch = 25.4 mm, 1 pound = 0.454 kg, 1 square foot = 0.93 m2.|For SI: 1 inch = 25.4 mm, 1 pound = 0.454 kg, 1 square foot = 0.93 m2.|For SI: 1 inch = 25.4 mm, 1 pound = 0.454 kg, 1 square foot = 0.93 m2.|For SI: 1 inch = 25.4 mm, 1 pound = 0.454 kg, 1 square foot = 0.93 m2.|

R905.2.8.3 Sidewall flashing. Base flashing against a vertical sidewall shall be continuous or step flashing and shall be not less than 4 inches (102 mm) in height and 4 inches (102 mm) in width and shall direct water away from the vertical sidewall onto the roof or into the gutter. Where siding is provided on the vertical sidewall, the vertical leg of the flashing shall be continuous under the siding. Where anchored masonry veneer is provided on the vertical sidewall, the base flashing shall be provided in accordance with this section and counterflashing shall be provided in accordance with Section R703.8.2.2. Where exterior plaster or adhered masonry veneer is provided on the vertical sidewall, the base flashing shall be provided in accordance with this section and Section R703.7.3.

R905.2.8.4 Other flashing. Flashing against a vertical front wall, as well as soil stack, vent pipe and chimney flashing, shall be applied in accordance with the asphalt shingle manufacturer’s instructions.

R905.2.8.5 Drip edge. A drip edge shall be provided at eaves and rake edges of shingle roofs. Adjacent segments of drip edge shall be overlapped not less than 2 inches (51 mm). Drip edges shall extend not less than [1] / 4 inch (6.4 mm) below the roof sheathing and extend up back onto the roof deck not less than 2 inches (51 mm). Drip edges shall be mechanically fastened to the roof deck at not more than 12 inches (305 mm) o.c. with fasteners as specified in Section R905.2.5. Underlayment shall be installed over the drip edge along eaves and under the drip edge along rake edges.

R905.3 Clay and concrete tile. The installation of clay and concrete tile shall comply with the provisions of this section.

R905.3.1 Sheathing requirements. Concrete and clay tile shall be installed over wood structural panels or solid lumber sheathing.

Exception: Spaced lumber sheathing in accordance with Section R803.1 shall be permitted in Seismic Design Categories A, B and C.
CBC § 8.4.1 High relevance — show source text
Fasteners shall be sized such that the tip of the fastener passes completely through the wood structural panel sheathing by not less than1/4 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 m [2] ) 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 D 0, D 1 or D 2 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 m [2] ) 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(1), 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.

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WALL COVERING

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.
CBC § 1401.1 High relevance — show source text
ICC code development note: Code change proposals to sections preceded by the designation [BS] will be considered by the IBC—Structural Code Development

Committee during the 2025 (Group B) Code Development Cycle.

SECTION 1401—GENERAL

1401.1 Scope. The provisions of this chapter shall establish the minimum requirements for exterior walls, exterior wall assemblies, exterior wall coverings, exterior wall openings, exterior windows and doors, exterior soffits and fascias, and architectural trim.

SECTION 1402—PERFORMANCE REQUIREMENTS

1402.1 General. The provisions of this section shall apply to exterior walls, exterior wall coverings and components thereof.

1402.2 Weather protection. Buildings shall be provided with a weather-resistant exterior wall assembly. The exterior wall assembly shall include flashing, as described in Section 1404.4. The exterior wall assembly shall be designed and constructed in such a manner as to prevent the accumulation of water within the exterior wall assembly by providing a water-resistive barrier behind the exterior veneer, as described in Section 1403.2, and a means for draining water that enters the assembly to the exterior. Protection against condensation in the exterior wall assembly shall be provided in accordance with Section 1404.3.

Exceptions:
1. A weather-resistant exterior wall assembly shall not be required over concrete or masonry walls designed in accordance with Chapters 19 and 21, respectively.
2. Compliance with the requirements for a means of drainage, and the requirements of Sections 1403.2 and 1404.4, shall not be required for an exterior wall assembly that has been demonstrated through testing to resist wind-driven rain, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E331 under the following conditions:
The exterior wall design shall be considered to resist wind-driven rain where the results of testing, in accordance with ASTM E331, indicate that water did not penetrate control joints in the exterior wall, joints at the perimeter of openings or intersections of terminations with dissimilar materials.

2.1. Exterior wall test assemblies shall include not fewer than one opening, one control joint, one wall/eave interface and one wall sill. Tested openings and penetrations shall be representative of the intended end-use configuration. 2.2. Exterior wall test assemblies shall be not less than 4 feet by 8 feet (1219 mm by 2438 mm) in size. 2.3. Exterior wall test assemblies shall be tested at a minimum differential pressure of 6.24 pounds per square foot (0.297 kN/m [2] ). 2.4. Exterior wall test assemblies shall be subjected to a minimum test exposure duration of 2 hours. 3. Exterior insulation and finish systems (EIFS) complying with Section 1407.4.1.

1402.2.1 [BSC-CG] See California Green Building Standards Code, Chapter 5, Division 5.4 for additional weather protection requirements.

[BS] 1402.3 Wind resistance. Exterior walls, exterior wall coverings, exterior soffits and fascias, and the associated openings, shall be designed and constructed to resist safely the superimposed loads required by Chapter 16.
CBC § 1.1 High relevance — show source text
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-resistive 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: 2.1. Exterior wall envelope test assemblies shall include at least one opening, one control joint, one wall/eave interface and one wall sill. All tested openings and penetrations shall be representative of the intended enduse configuration. 2.2. Exterior wall envelope test assemblies shall be at least 4 feet by 8 feet (1219 mm by 2438 mm) in size. 2.3. Exterior wall assemblies shall be tested at a minimum differential pressure of 6.24 pounds per square foot (299 Pa). 2.4. Exterior wall envelope assemblies shall be subjected to the minimum test exposure for a minimum of 2 hours. The exterior wall envelope design shall be considered to resist wind-driven rain where the results of testing indicate that water did not penetrate control joints in the exterior wall envelope, joints at the perimeter of openings penetration or intersections of terminations with dissimilar materials.
R703.1.2 Wind resistance. Wall coverings, backing materials and their attachments shall be capable of resisting wind loads in accordance with Tables R301.2.1(1) and R301.2.1(2). Wind-pressure resistance of the siding, exterior 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, exterior 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, exterior 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. Not fewer than one layer of water-resistive barrier shall be applied over studs or sheathing of all exterior walls with flashing as indicated in Section R703.4, in such a manner as to provide a continuous water-resistive barrier behind the exterior wall veneer and behind deck ledgers. The 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.

CBC § 8.2.2 Medium relevance — show source text

SHEATHING

BRICK VENEER

STUD

STEEL ANGLE NOT ATTACHED TO STUD

FASTENERS

VENEER TIE

FLASHING

WEEP HOLE

COUNTER FLASHING

BASE FLASHING

TRIPLE RAFTERS ATTACHED TO STUDS

BR VE FL TRIP ATTA	BR VE FL	Col3	Col4	Col5
BR VE FL TRIP ATTA	BR VE FL
BR VE FL TRIP ATTA
BR VE FL TRIP ATTA
BR VE FL TRIP ATTA
BR VE FL TRIP ATTA
BR VE FL TRIP ATTA
BR VE FL TRIP ATTA
BR VE FL TRIP ATTA

FIGURE R703.8.2.2(2)—EXTERIOR MASONRY VENEER SUPPORT BY LEDGER

WATER RESISTIVE BARRIER

SHEATHING

BRICK VENEER

STEEL ANGLE NOT ATTACHED TO STUD

WEEP HOLE

METAL FLASHING AND COUNTERFLASHING

BASE FLASHING

ROOFING

ROOFING FELT

ROOF SHEATHING

TRIPLE LEDGER ATTACHED TO STUD

FASTENERS

ROOF FRAMING

STUD

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 R703.8.3.2.

R703.8.3.1 Allowable span. The allowable span shall not exceed the values set forth in Table R703.8.3.1.

2025 CALIFORNIA RESIDENTIAL CODE 7-21

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WALL COVERING

TABLE R703.8.3.1—ALLOWABLE SPANS FOR LINTELS SUPPORTING MASONRY VENEERa, b, c, d	Col2	Col3	Col4	Col5
SIZE OF STEEL ANGLEa, c, d (inches)	NO STORY ABOVE	ONE STORY ABOVE	TWO STORIES ABOVE	** NO.

CBC § 403.4.7 Medium relevance — show source text
Smoke exhaust 910 Smoke removal, high-rise buildings 403.4.7 Smokeproof enclosure 909.20.3, 909.20.5, 1023.12 Spray rooms and spaces 416.2.2, 416.3 Stages 410.2.5, 410.2.7 Under-floor ventilation 202.4 Vents, Penetration Protection 714 Vermiculite, Fire Resistant 721 Vertical Opening Protection Atriums 404.6

Duct penetrations 717.1 Elevators 713.14, 3007.6.1, 3008.6.1 Exceptions 1019, 1023.2 Group I-3 408.5 High-rise 403.2.1.2, 403.2.2, 403.5.1 Live/work units 508.5.6 Open parking garages 406.5.9 Permitted vertical openings 712 Shaft enclosure 713, 1019, 1023.2 Vestibules, Exit Discharge 1028.2 Vinyl Expanded 803.7, 803.8 Rigid 1404.15 Violations 114 Voice Alarm (see Alarms, Voice) Walkway 402.4.3.1, 3104 During construction 3306 Encroachment, public right-of-way 3202.3.4

Fire resistance Table 601

Live load Table 1607.1 Materials per construction type Chapter 6 Opening protection 716, 717, 1026.2 Wall, Exterior 705, 1401 Bearing Chapter 6

California Energy Code and International Energy Conservation Code Climate Zones 1404.3.3 Combustible wall covering 1405 Coverings 1404 Drawings 107.2.4 Exterior insulation and finish systems (EIFS) 1407 Exterior structural members 704.9

Fire district D102.2.6, D102.1 Fire-resistance ratings 703, 705.5, Table 705.5, 706.5.1, 707.4, 1402.4 Flashing, veneered walls 1404.11.1, 1404.4

Foam plastic insulation 2603.4.1.4, 2603.5 Glazing, rated 715.8 Joints 705.10, 714 Light-transmitting plastic panels 2607 Materials 705.4, 1403.1, 1405 Metal composite material (MCM) 1406 Nonbearing Chapter 6 Opening protection 705.11, 705.9, 716.2.5.4

Parapets 705.12 Performance requirements 1402 Projections 705.2 Structural stability 705.7 Vapor retarders 1404.3 Veneer (see Veneer) Weather resistance 1402.2, 1404.2, 1406.6, 1407.4 Weather-resistant barriers 1404.2 Wall, Fire (see Fire Walls) Wall, Foundation (see Foundations) Wall, Interior Finishes 803, 1210.2 Opening protection 716, 717 Wall, Interior Nonbearing (See Partitions) Wall, Masonry 202 Wood Contact 2304.12.1.3,
CBC § 1.2 Medium relevance — show source text
1_||X||||||||||||||||||||||| |1403|||X|||||||||||||||||||||| |1404|||X|||||||||||||||||||||| |1404.1.2||||||||X|X|X|X|X||X|X|||||||||| |1404.3.3|||||||||||||||||||||X|||| |1405|||X|||||||||||||||||||||| |1406|||X|||||||||||||||||||||| |1407|||X|||||||||||||||||||||| |1408|||X|||||||||||||||||||||| |1411|||X|||||||||||||||||||||| |1412|||X|||||||||||||||||||||| |1413||||||||X|X|X|X|X||X|X||||||||||

The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

2025 CALIFORNIA BUILDING CODE 14-1

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

14-2 2025 CALIFORNIA BUILDING CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

14 EXTERIOR WALLS

User notes:

About this chapter: Chapter 14 addresses requirements for exterior walls of buildings. Minimum standards for wall covering materials, such as material performance and fire resistance, installation of wall coverings and the ability of the wall to provide weather protection are provided. This chapter also contains limitations on the areas and heights of combustible wall coverings based on fire separation distances, radiant heat exposure and surface burning characteristics.

ICC code development note: Code change proposals to sections preceded by the designation [BS] will be considered by the IBC—Structural Code Development

Committee during the 2025 (Group B) Code Development Cycle.

SECTION 1401—GENERAL

1401.1 Scope. The provisions of this chapter shall establish the minimum requirements for exterior walls, exterior wall assemblies, exterior wall coverings, exterior wall openings, exterior windows and doors, exterior soffits and fascias, and architectural trim.

SECTION 1402—PERFORMANCE REQUIREMENTS

1402.1 General. The provisions of this section shall apply to exterior walls, exterior wall coverings and components thereof.

1402.2 Weather protection. Buildings shall be provided with a weather-resistant exterior wall assembly. The exterior wall assembly shall include flashing, as described in Section 1404.4. The exterior wall assembly shall be designed and constructed in such a manner as to prevent the accumulation of water within the exterior wall assembly by providing a water-resistive barrier behind the exterior veneer, as described in Section 1403.2, and a means for draining water that enters the assembly to the exterior. Protection against condensation in the exterior wall assembly shall be provided in accordance with Section 1404.3.

Exceptions:
1. A weather-resistant exterior wall assembly shall not be required over concrete or masonry walls designed in accordance with Chapters 19 and 21, respectively.
2. Compliance with the requirements for a means of drainage, and the requirements of Sections 1403.2 and 1404.4, shall not be required for an exterior wall assembly that has been demonstrated through testing to resist wind-driven rain, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E331 under the following conditions:
CBC § 2.6 Medium relevance — show source text
Fire district D102.2.6, D102.1 Fire-resistance ratings 703, 705.5, Table 705.5, 706.5.1, 707.4, 1402.4 Flashing, veneered walls 1404.11.1, 1404.4

Foam plastic insulation 2603.4.1.4, 2603.5 Glazing, rated 715.8 Joints 705.10, 714 Light-transmitting plastic panels 2607 Materials 705.4, 1403.1, 1405 Metal composite material (MCM) 1406 Nonbearing Chapter 6 Opening protection 705.11, 705.9, 716.2.5.4

Parapets 705.12 Performance requirements 1402 Projections 705.2 Structural stability 705.7 Vapor retarders 1404.3 Veneer (see Veneer) Weather resistance 1402.2, 1404.2, 1406.6, 1407.4 Weather-resistant barriers 1404.2 Wall, Fire (see Fire Walls) Wall, Foundation (see Foundations) Wall, Interior Finishes 803, 1210.2 Opening protection 716, 717 Wall, Interior Nonbearing (See Partitions) Wall, Masonry 202 Wood Contact 2304.12.1.3,

2304.12.2.1

Wall, Parapet 705.12, 1503.3, 2109.2.4.3 Wall, Party (See Fire Walls) Wall, Penetrations 714.4 Wall, Retaining (See Retaining Wall) Wall, Veneered (See Veneer) Chapter 14 Wall, Wood Construction Bracing 2308.10 Cripple walls 2308.9.6 Cutting, notching and boring of dimensional wood framing 2308.6 Exterior framing 2308.9 Fastening schedule Table 2304.10.2 Framing 2304.3, 2308.9 Hillside light-frame construction 2308.2.7 Interior bearing partition 2308.9.4 Interior nonbearing partition 2308.9.1 Openings 2308.9.5 Shear walls 2305.1, 2306.3 Sheathing (see Sheathing) Studs 2308.9.1 Top plates 2308.9.3.2 Waste, Construction 420.12 Water-Reactive Materials Table 307.1(1), 307.4, 307.5. 415.8.4

Weather Protection

Exterior walls 1404.2

Roofs 1503 Welding Materials, verification of steel reinforcement 1705.3.2 Special inspections 1705.13.3, 1705.2, 1705.3.1 Splices of reinforcement in masonry 2107.3, 2108.3 Wildland-Urban Interface 101.4.8

Wind Load 1609 Basic design wind speed 1609.3 Construction documents

107, 1603.1.4 Exposure category 1609.4 Glazing 1609.2, 2404 Hurricane 1507.1.1 Masonry,
CBC § 2.4. Medium relevance — show source text
2.4. Exterior wall envelope assemblies shall be subjected to the minimum test exposure for a minimum of 2 hours. The exterior wall envelope design shall be considered to resist wind-driven rain where the results of testing indicate that water did not penetrate control joints in the exterior wall envelope, joints at the perimeter of openings penetration or intersections of terminations with dissimilar materials.

R703.1.2 Wind resistance. Wall coverings, backing materials and their attachments shall be capable of resisting wind loads in accordance with Tables R301.2.1(1) and R301.2.1(2). Wind-pressure resistance of the siding, exterior 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, exterior 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, exterior 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. Not fewer than one layer of water-resistive barrier shall be applied over studs or sheathing of all exterior walls with flashing as indicated in Section R703.4, in such a manner as to provide a continuous water-resistive barrier behind the exterior wall veneer and behind deck ledgers. The 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. Where the water-resistive barrier also functions as a component of a continuous air barrier, the waterresistive barrier shall be installed as an air barrier in accordance with Section N1102.5.1.1. Water-resistive barrier materials shall comply with one of the following:
1. No. 15 felt complying with ASTM D226, Type 1.
2. ASTM E2556, Type 1 or 2.
3. Foam plastic insulating sheathing water-resistive barrier systems complying with Section R703.1.1 and installed in accordance with the manufacturer’s installation instructions.
4. ASTM E331 in accordance with Section R703.1.1.
5. Other approved materials in accordance with the manufacturer’s installation instructions. No.15 asphalt felt and water-resistive barriers complying with ASTM E2556 shall be applied horizontally, with the upper layer lapped over the lower layer not less than 2 inches (51 mm), and where joints occur, shall be lapped not less than 6 inches (152 mm). Exception: A water-resistive barrier shall not be required in unconditioned detached tool sheds, storage sheds, playhouses, and other similar accessory structures provided all of the following requirements are met:
6. Exterior wall covering is limited to siding that is attached direct to studs.
7. Exterior walls are uninsulated.
8. Interior side of exterior walls has no wall covering or wall finishes. 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.
CBC § 1404.11.1 Medium relevance — show source text
[BS] 1404.11.1 Exterior adhered masonry veneer. Exterior adhered masonry veneer shall be installed in accordance with Section 1404.11 and the manufacturer’s instructions.

[BS] 1404.11.1.1 Water-resistive barriers. Water-resistive barriers shall be installed as required in Section 2510.6.

[BS] 1404.11.1.2 Flashing. Flashing shall comply with the applicable requirements of Sections 1404.4 and 1404.11.1.2.1.

[BS] 1404.11.1.2.1 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 3 [1] / 2 inches (89 mm) shall be installed to extend not less than 1 inch (25 mm) below the foundation plate line on exterior stud walls in accordance with Section 1404.4. The water-resistive barrier shall lap over the exterior of the attachment flange of the screed or flashing.

[BS] 1404.11.1.3 Clearances. On exterior stud walls, adhered masonry veneer shall be installed not less than 4 inches (102 mm) above the earth, or not less than 2 inches (51 mm) above paved areas, or not less than [1] / 2 inch (12.7 mm) above exterior walking surfaces that are supported by the same foundation that supports the exterior wall.

[BS] 1404.11.1.4 Adhered masonry veneer installed with lath and mortar. Exterior adhered masonry veneer installed with lath and mortar shall comply with the following.

[BS] 1404.11.1.4.1 Lathing. Lathing shall comply with the requirements of Section 2510.

[BS] 1404.11.1.4.2 Scratch coat. A nominal [1] / 2 -inch-thick (12.7 mm) layer of mortar complying with the material requirements of Sections 2103 and 2512.2 shall be applied, encapsulating the lathing. The surface of this mortar shall be scored horizontally, resulting in a scratch coat.

[BS] 1404.11.1.4.3 Adhering veneer. The masonry veneer units shall be adhered to the mortar scratch coat with a nominal 1 / 2 -inch-thick (12.7 mm) setting bed of mortar complying with Sections 2103 and 2512.2 applied to create a full setting bed for the back of the masonry veneer units. The masonry veneer units shall be worked into the setting bed resulting in a nominal [3] / 8 -inch (9.5 mm) setting bed after the masonry veneer units are applied.

[BS] 1404.11.1.5 Adhered masonry veneer applied directly to masonry and concrete. Adhered masonry veneer applied directly to masonry or concrete shall comply with the applicable requirements of Section 1404.11 and with the requirements of Section 1404.11.1.4 or 2510.7.

[BS] 1404.11.1.6 Cold weather construction. Cold weather construction of adhered masonry veneer shall comply with the requirements of Sections 2104 and 2512.4.

Frequently asked questions

Do I have to use 26‑gauge metal for every flashing on the job?

No. The 0.019‑inch (26 ga) minimum specifically applies to the corrosion‑resistant screed/flashing at the foundation for exterior adhered masonry veneer per § 1404.11.1.2.1. Other flashings (windows, counterflashing, copings) must be corrosion‑resistant and sized per § 1404.4 or the applicable manufacturer/RDP instructions; the code does not mandate 26 ga for every flashing location.

Can I rely on a window maker’s generic detail for fenestration flashing?

Yes — the fenestration manufacturer’s instructions are the primary acceptable method. If the manufacturer’s instructions do not cover the condition, the code allows using the WRB manufacturer’s instructions, the flashing manufacturer’s instructions, an RDP design, or another approved method per § 1404.4.1.

How high above grade must masonry veneer flashing be placed?

For anchored masonry veneer (per § 1404.7 design), flashing and weep holes shall be located not more than 10 in (245 mm) above finished ground level above the foundation wall or slab; at other points of support flashing/weep holes shall be located in the first course of masonry above the support. See § 1404.4.3.

Must the WRB lap over the screed flange on adhered veneer?

Yes. § 1404.11.1.2.1 requires the WRB to lap over the exterior of the screed/attachment flange for exterior adhered masonry veneer.

If a tested wall assembly resists wind‑driven rain, can I omit flashing?

The CBC allows omission of certain drainage/WRB/flashings only when the entire exterior wall assembly (including representative openings and terminations) has been shown by ASTM E331 testing to resist wind‑driven rain under the specific test conditions in § 1402.2. Consult § 1402.2 for the test requirements before omitting flashing.

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