CEBC · California Existing Building Code

Which Appendix A chapters apply to my building type (URM, RC/masonry, light-frame)?

Q: How do I know if a masonry wall is a "bearing" wall under Appendix A?

If the wall is URM and the superimposed vertical load it supports exceeds 100 plf , it is an Unreinforced Masonry Bearing Wall under the Appendix definitions (see § A103 ).

Q: My building is RC with plywood diaphragms — can I use Chapter A2?

Chapter A2 is intended for reinforced concrete or reinforced masonry wall buildings with flexible diaphragms . You must confirm the diaphragm classification (flexible vs rigid) per the Appendix definitions before selecting A2. See § A202 and Appendix definitions. file

If your building has **URM bearing walls** (walls carrying more than **100 plf**), Chapter **A1** applies; if it is a **reinforced concrete or reinforced masonry wall** building with a **flexible diaphragm**, Chapter **A2** applies; light‑frame residential issues are in Chapters **A3/A4** — but Appendix A methods are specifically cited for **Risk Category I or II** in **§ 304.3.2**, and agency adoption/vesting rules in **§ A100.1** can affect whether your project may use those Appendix A procedures. filefile

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

Appendix A is organized by construction type; which chapter you may use depends on the building’s structural system, diaphragm type, and the Risk Category. The CEBC explicitly allows use of the Appendix A chapters as a compliance method for certain building types assigned to Risk Category I or II — see § 304.3.2.

The single most important rule: If your building is an Unreinforced Masonry (URM) bearing wall building, or a reinforced concrete / reinforced masonry wall building with a flexible diaphragm, or a light‑frame residential building with cripple walls or soft/weak/open front walls, Appendix A contains the targeted chapter you can use — but only under the Risk Category limits in § 304.3.2.

Requirements in detail

Short map: which chapter for which building type

Chapter A1 — seismic strengthening provisions for Unreinforced Masonry (URM) bearing wall buildings. See § A102 and the application/agency vesting § A100.1.
Chapter A2 — earthquake hazard reduction for reinforced concrete and reinforced masonry wall buildings with flexible diaphragms. See § A202.
Chapter A3 / A4 — prescriptive provisions for light‑frame wood residential buildings (cripple walls, sill anchorage, soft/weak/open-front walls). These are also identified in the CEBC mapping of Appendix A chapters.

All three mappings above are explicitly listed as options under § 304.3.2 for reduced seismic criteria (items 2.1–2.4).

Key definitions and thresholds you must check (first mention bolded)

Unreinforced Masonry (URM) — includes burned clay, concrete or sand‑lime brick; hollow clay or concrete block; plain concrete; and hollow clay tile. See § A103 for the Appendix A definitions.
Unreinforced Masonry Bearing Wall — a URM wall that carries vertical reaction for which the total superimposed vertical load exceeds 100 pounds per linear foot (plf) of wall length. This 100 plf threshold is decisive for whether a URM wall is “bearing” under Appendix A. See § A103.
Flexible diaphragm — a diaphragm of wood or untopped metal deck construction in which horizontal deformation along its length is at least two times the average story drift (definition in the Appendix A definitions). See § A103.
Risk Category I or II — Appendix A chapters are cited by the CEBC as applicable to buildings assigned to Risk Category I or II when using the Appendix A compliance methods. See § 304.3.2.

Decision table (use to determine which chapter applies)

Building type (plain English)	Decision‑relevant dimension / value (what you must confirm)	When that Appendix A chapter applies	Code Reference
Unreinforced masonry bearing‑wall	Is the wall URM? Does it carry > 100 plf superimposed vertical load? Is building assigned Risk Category I or II?	Use Chapter A1 when URM bearing walls are present and Risk Category I or II	§ A102, § A103, § 304.3.2 filefile
Reinforced concrete / reinforced masonry walls	Are walls reinforced? Do they form the lateral system? Is the diaphragm flexible? Risk Category I or II?	Use Chapter A2 for RC or reinforced masonry wall buildings with flexible diaphragms assigned to Risk Category I or II	§ A202, § 304.3.2 file
Light‑frame wood residential (cripple walls / sill anchorage)	Is the building light‑frame residential? Are there cripple walls or sill anchorage issues? Risk Category I or II?	Use Chapter A3 (cripple walls & sill anchors) or A4 (soft/weak/open front walls) for light‑frame residential in Risk Category I or II	§ 304.3.2

Required documentation & QA when you use an Appendix A chapter

If you use Appendix A methods, the Appendix requires specific plans and QA items — e.g., dimensioned plans showing existing URM walls, wall classes, test locations, and anchor prequalification program details; and structural observation / special inspection for retrofit work. See § A105.3 and § A105.4.

Exceptions & special cases

Appendix A chapters are presented in CEBC as one of the compliance options for reduced seismic criteria and are limited by the CEBC mapping — primarily targeted at Risk Category I and II buildings. For other Risk Categories, different methods (e.g., ASCE 41 or full CBC Section 1613 approaches) govern. See § 304.3.2.
State agency adoption varies: some agencies adopt entire chapters or specific sections (vesting/enforcing agency details are set out in § A100.1 and the adoption matrix). That affects whether a state enforcement agency will accept Appendix A procedures for a given building. See § A100.1 and the Appendix A adoption matrix. file
Non‑bearing URM: for some state‑owned buildings where URM is not bearing, URM may be allowed only to resist lateral loads and must be assessed differently (see § 319.1.3). Public schools have additional restrictions on URM use. See § 319.1.3 and § 319.1.4.
Materials with special provisions (adobe, stone) have their own h/t ratio limits and shear values (see § A114.1 for adobe/stone). If your walls are adobe/stone, check those limits before applying A1 wholesale.

Common mistakes

Treating any masonry wall as “URM bearing” without checking the >100 plf threshold. That 100 plf is explicit — see § A103.
Assuming Appendix A applies for Risk Categories beyond I or II. The CEBC mapping in § 304.3.2 limits Appendix A’s direct applicability.
Confusing diaphragm type: using Chapter A2 when diaphragms are actually rigid (A2 targets flexible diaphragms). Confirm diaphragm classification per Appendix definitions. See § A103 and § A202. file
Not providing the Appendix‑required plan content and special inspection/structural observation called out in § A105.3 and § A105.4 when submitting a permit.

Worked example — concrete scenario with numbers

Scenario: A two‑story commercial building has exterior brick walls (hollow clay brick), each wall supporting floor/roof reactions. The measured superimposed vertical load tributary to a typical wall is 160 plf. The building is assigned Risk Category II.

Step 1 — Is the wall URM bearing?

The wall material (brick, hollow clay) is within the Appendix definition of URM. The tributary vertical load is 160 plf, which exceeds the 100 plf threshold, so this is an Unreinforced Masonry Bearing Wall per § A103.

Step 2 — Which Appendix A chapter applies?

CEBC § 304.3.2 lists Chapter A1 for unreinforced masonry bearing wall buildings assigned to Risk Category I or II; this building is Risk Category II, so Chapter A1 is applicable as a compliance method. See § 304.3.2 and § A102. file

Step 3 — What to submit / do next (per Appendix A):

Prepare dimensioned plans showing existing URM walls, wall class, openings, and proposed retrofit measures per § A105.3; expect the structural observation and special inspection requirements in § A105.4 during retrofit. Use the analysis/design procedures in Chapter A1 (A109–A113 as applicable). file

Result: You may proceed to design using Chapter A1 provisions; do not assume A2/A3 apply (they are for different systems). Confirm agency adoption/vesting per § A100.1 if this is a state‑regulated building.

Related provisions (quick list)

Appendix A — Guidelines for the Seismic Retrofit of Existing Buildings (general context) — § Appendix A.
Vesting authority / agency adoption — § A100.1.
Chapter A1 scope/purpose (URM) — § A102.
Appendix A definitions (URM, URM bearing wall, flexible diaphragm) — § A103.
General requirements / plans / QA for Appendix A work — § A105.1, § A105.3, § A105.4.
Chapter A2 scope (RC / reinforced masonry with flexible diaphragms) — § A202.
CEBC provision identifying Appendix A chapters usable under reduced seismic criteria — § 304.3.2.
State‑specific limitations for URM/nonbearing and public schools — § 319.1.3 and § 319.1.4.
Adobe/stone special limits (height‑to‑thickness) — § A114.1.

Code references

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

California Existing Building Code High relevance — show source text
A109 Analysis and Design Procedure . . . . . . . APPENDIX A-10

A110 General Procedure . . . . . . . . . . . . . . . . . . APPENDIX A-10

A111 Special Procedure. . . . . . . . . . . . . . . . . . . APPENDIX A-11

A112 Analysis and Design . . . . . . . . . . . . . . . . . APPENDIX A-14

A113 Detailed Building System Design Requirements . . . . . . . . . . . . . . . . . . . . APPENDIX A-15

A114 Walls of Unburned Clay, Adobe or Stone Masonry. . . . . . . . . . . . . . . . . . . . APPENDIX A-17

CONTENTS

CHAPTER A2 EARTHQUAKE HAZARD REDUCTION IN EXISTING REINFORCED CONCRETE AND

REINFORCED MASONRY WALL BUILDINGS

WITH FLEXIBLE DIAPHRAGMS. . . . . . . . . . . . APPENDIX A-21

A201 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A-21

A202 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A-21

A203 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A-21

A204 Symbols and Notations . . . . . . . . . . . . . . APPENDIX A-21

A205 General Requirements . . . . . . . . . . . . . . . APPENDIX A-21

A206 Analysis and Design. . . . . . . . . . . . . . . . . . APPENDIX A-22

A207 Materials of Construction . . . . . . . . . . . . APPENDIX A-23

CHAPTER A3 PRESCRIPTIVE PROVISIONS FOR SEISMIC

STRENGTHENING OF CRIPPLE WALLS AND SILL PLATE

ANCHORAGE OF LIGHT, WOOD-FRAME RESIDENTIAL BUILDINGS. . . . . . . . . . . . . . . . APPENDIX A-27

A301 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A-27

A302 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A-27

A303 Structural Weaknesses. . . . . . . . . . . . . . . APPENDIX A-28

A304 Strengthening Requirements . . . . . . . . . APPENDIX A-28

CHAPTER A4 EARTHQUAKE RISK REDUCTION IN WOOD-FRAME RESIDENTIAL BUILDINGS WITH

SOFT, WEAK OR OPEN FRONT WALLS . . . . . APPENDIX A-45

A401 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A-45
CEBC § 1.3.8 High relevance — show source text
1.3.8 Structural design criteria. Where design is based on ASCE 7, Chapters 16, 17, 18 or 31, the seismic ground motion, wind tunnel test-based design recommendations, analysis and design methods, material assumptions, testing requirements and acceptance criteria shall be submitted to the enforcement agency as an alternative system.

[DSA-SS] Peer review requirements in Section 322 of the California Existing Building Code shall apply to design reviews required by ASCE 7, Chapters 17, 18, 31 and ASCE 49.

[OSHPD 1 & 4] Peer review requirements in Section 1617A.1.41 of this code shall apply to design reviews required by ASCE 7, Chap- ters 17 and 18.

1617A.1.2 ASCE 7, Section 11.1.3. Replace last paragraph of ASCE 7, Section 11.1.3, by the following:

Non-building structures similar to buildings shall be designed and detailed in accordance with Chapter 12.

1617A.1.3 Reserved.

1617A.1.4 ASCE 7, Table 12.2-1. Modify ASCE 7, Table 12.2-1 as follows:

A. BEARING WALL SYSTEMS

6. Intermediate Precast Shear Walls —Not permitted by OSHPD.

18 . Light-framed walls with shear panels of all other materials —Not permitted by OSHPD and DSA-SS.

B. BUILDING FRAME SYSTEMS
1. Steel ordinary concentrically braced frames— Not permitted by OSHPD.
9 . Intermediate Precast Shear Walls —Not permitted by OSHPD.

25 . Light-framed walls with shear panels of all other materials —Not permitted by OSHPD and DSA-SS.

27 . Special steel plate shear wall —Not permitted by OSHPD.

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STRUCTURAL DESIGN

C . MOMENT-RESISTING FRAME SYSTEMS
1. Steel special truss moment frames —Not permitted by OSHPD.
2. Steel intermediate moment frames —Not permitted by OSHPD except for single-story canopies and independent covered walkways where R, C d and Ω 0 = 1.5 and the roof dead load is less than 20 psf.
3. Steel ordinary moment frames —Not permitted by OSHPD except for single-story canopies and independent covered walk- ways where R, C d and Ω 0 = 1.5 and the roof dead load is less than 20 psf.
4. Cold-formed steel–special bolted moment frame —Not permitted by DSA-SS and OSHPD.
G. CANTILEVER COLUMN SYSTEMS DETAILED TO CONFORM WITH THE REQUIREMENTS FOR:
1. Steel special cantilever column systems —Not permitted by OSHPD except for single-story canopies and independent covered walkways where R, C d and Ω 0 = 1.5 and roof dead load is less than 20 psf.
California Existing Building Code High relevance — show source text
900 plf|W|25|24|24|19|19|18|15|15|17|13|15|17|13|15|17|13|15|17| |4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry| |1-story|1,500 plf|D|4|4|4|4|4|4|4|4|4|4|4|4|4|4|4|4|4|4| |1-story|1,500 plf|W|13|15|17|13|15|17|13|15|17|13|15|17|13|15|17|13|15|17| |2-story|2,700 plf|D|12|11|9|8|6|4|5|4|4|4|4|4|4|4|4|4|4|4| |2-story|2,700 plf|W|22|23|23|18|17|17|14|15|17|13|15|17|13|15|17|13|15|17| |3-story|4,000 plf|D|21|20|18|14|13|11|10|8|7|7|6|4|5|4|4|4|4|4| |3-story|4,000 plf|W|33|34|33|25|26|25|20|20|21|17|17|17|14|15|17|13|15|17| |8-inch solid or fully grouted masonry|8-inch solid or fully grouted masonry|8-inch solid or fully grouted masonry|8-inch solid or fully grouted masonry|8-inch solid or fully grouted masonry|**8-inch solid or fully grouted

CEBC § 304.3.2 High relevance — show source text

[BS] 304.3.2 Reduced seismic criteria. Where required, seismic evaluation or design shall comply with one of the following methodologies, which shall not be applied in combination with each other:

Section 1613 of the California Building Code using 75 percent of the prescribed forces. Values of R, Ω 0 and C d used for analysis shall be as specified in Section 304.3.1 of this code.

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PROVISIONS FOR ALL COMPLIANCE METHODS

Applicable chapters of Appendix A of this code, for structures or portions of structures specified in Items 2.1 through 2.4 subject to the limitations of the respective chapter. 2.1. Chapter A1 for unreinforced masonry bearing wall buildings assigned to Risk Category I or II. 2.2. Chapter A2 for the wall anchorage system in reinforced concrete and reinforced masonry wall buildings with flexible diaphragms assigned to Risk Category I or II. 2.3. Chapter A3 for cripple walls and sill plate anchorage in residential buildings of light-frame wood construction assigned to Risk Category I or II. 2.4. Chapter A4 for soft, weak or open-front wall conditions in multiple-unit residential buildings of wood construction assigned to Risk Category I or II.
ASCE 41, using the performance objective in Table 304.3.2 for the applicable risk category.

[BS] TABLE 304.3.2—PERFORMANCE OBJECTIVES FOR USE IN ASCE 41 FOR COMPLIANCE WITH REDUCED CRITERIA FORCES	Col2	Col3
RISK CATEGORY (Based on IBC Table 1604.5)	STRUCTURAL PERFORMANCE LEVEL FOR USE WITH BSE-1E EARTHQUAKE HAZARD LEVEL	STRUCTURAL PERFORMANCE LEVEL FOR USE WITH BSE-2E EARTHQUAKE HAZARD LEVEL
I	Life Safety (S-3). See Note a	Collapse Prevention (S-5)
II	Life Safety (S-3). See Note a	Collapse Prevention (S-5)
III	Damage Control (S-2). See Note a	Limited Safety (S-4). See Note b
IV	Immediate Occupancy (S-1)	Life Safety (S-3). See Note c
a. For Risk Categories I, II and III, the Tier 1 and Tier 2 procedures need not be considered for the BSE-1E earthquake hazard level. b. For Risk Category III, the Tier 1 screening checklists shall be based on the Collapse Prevention, except that checklist statements using the Quick Check provisions shall be based on_MS_-factors that are the average of the values for Collapse Prevention and Life Safety. c. For Risk Category IV, the Tier 1 screening checklists shall be based on Collapse Prevention, except that checklist statements using the Quick Check provisions shall be based on_MS_-factors for Life Safety.	a. For Risk Categories I, II and III, the Tier 1 and Tier 2 procedures need not be considered for the BSE-1E earthquake hazard level. b.

CEBC § 1617.12.1 High relevance — show source text
1617.12.1 ASCE 7, Section 1.3. Modify ASCE 7, Section 1.3 by adding Section 1.3.8 as follows:

1.3.8 Structural design criteria. Where design is based on ASCE 7, Chapters 16, 17, 18 or 31, the seismic ground motion, wind tunnel test based design recommendations, analysis and design methods, material assumptions, testing requirements and acceptance criteria shall be submitted to the enforcement agency as an alternative system.

Peer review requirements in Section 322 of the California Existing Buildings Code shall apply to design reviews required by ASCE 7, Chapters 17, 18, 31 and ASCE 49.

1617.12.2 ASCE 7, Table 12.2-1. Modify ASCE 7, Table 12.2-1 as follows:

A. BEARING WALL SYSTEMS
1. Light-framed walls with shear panels of all other materials —Not permitted by DSA-SS/CC.
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STRUCTURAL DESIGN

B. BUILDING FRAME SYSTEMS
1. Light-framed walls with shear panels of all other materials —Not permitted by DSA-SS/CC.
C. MOMENT RESISTING FRAME SYSTEMS
1. Cold-formed steel — special bolted moment frame— Not permitted by DSA-SS/CC.
Exceptions: 1. Systems listed in this section can be used as an alternative system when pre-approved by the enforcement

agency. 2. Rooftop or other supported structures not exceeding two stories in height and 10 percent of the total struc- ture weight can use the systems in this section when designed as components per ASCE 7, Chapter 13. 3. Systems listed in this section can be used for seismically isolated buildings when permitted by ASCE 7, Section 17.2.5.4.

1617.12.3 ASCE 7, Section 12.2.5.6.1. The exception in Item a is not permitted by DSA-SS/CC.

1617.12.4 ASCE 7, Section 12.2.5.7.1. The exception in Item a is not permitted by DSA-SS/CC.

1617.12.5 ASCE 7, Section 12.2.5.7.2. The exception in Item a is not permitted by DSA-SS/CC.

1617.12.6 ASCE 7, Section 12.3.3.1. Replace ASCE 7, Section 12.3.3.1 by the following:

12.3.3.1 Prohibited vertical irregularities for Seismic Design Categories D through F. Structures assigned to Seismic Design Category E or F that have vertical irregularities Type 1b, 4a or 4b of Table 12.3-2 shall not be permitted. Structures assigned to Seismic Design Category D having vertical irregularity Type 1b or 4b of Table 12.3-2 shall not be permitted.
CEBC § 2205.1 High relevance — show source text
Cold-Formed Steel 2204

Cold-formed Stainless Steel 2205.1 Cutting and notching 2206.3 Light-frame construction 2206 Special inspection 1705.12.2, 1705.13.3, 1705.2.3, 1705.2.7 Combustible Dusts 307.4, 414.5.1, 426.1 Combustible Liquids 307.1, 307.4, 307.5, 414.2.5, 414.5.3, 415.9.2, 415.10.1, 418.6

Combustible Material

Concealed spaces 413.2, 718.5 Exterior side of exterior wall 1405 High-pile stock or rack storage 413.1, 910.2.2 Type I and Type II 603, 805 Combustible Projections 705.2, 705.2.3.1 Combustible Storage 413, 910.2.2 Common Path of Egress Travel 1006.2.1 Compartmentation Ambulatory care facilities 422.2, 422.3 Group I-2 407.5, 407.6 Group I-3 408.6 Laboratory suites 428.3 Underground buildings 405.4, 405.5.2 Compressed Gas 307.2, 415.11.8 Concealed Spaces 413.2, 718 Concrete Chapters 19 and 19A Anchorage 1901.3 Calculated fire resistance 722.2

Cellular 721.2

Construction documents 1603.1,

1901.5 Durability 1904 Footings 1809, 1906 Foundation walls 1807.1.5, 1808.8 Materials 1705.3.2, 1901, 1903 Plain, structural 1906 Reinforced gypsum concrete 2514 Rodentproofing Appendix F Roof tile 1504.3, 1507.3, 1513 Shotcrete 1908 Slabs-on-ground 1907 Special inspections 1705.3, Table 1705.3 Specifications 1903 Strength testing 1705.3.2 Structural concrete with GFRP

reinforcement 1901.2.1 Wood support 2304.13 Concrete Masonry Calculated fire resistance 722.3

Construction 2104

Design 2101.2, 2108, 2109 Materials 2103.1 Surface bonding 2103.2.2, 2109.2 Wood support 2304.13 Concrete Roof Tile 1504.3, 1507.3, 1513 Wind Resistance 1504.3, 1609.6.3.1 Condominium (see Apartment Houses) Conduit, Penetration Protection 713.3,

1023.5 Conflicts in Code 102, 104.2.4.1 Congregate Living Facilities 310.2, 310.3, 310.4

Construction (See Safeguards During Construction) Construction Documents 107, 1603 Alarms and detection 907.1.1

Balconies 107.2.5
CEBC § 2.3.9 High relevance — show source text
Σ W d = Total dead load of all the diaphragms at and above the level under consideration, pounds (N).

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APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS

SECTION A105—GENERAL REQUIREMENTS

[BS] A105.1 General. The seismic force-resisting system specified in this chapter shall comply with the California Building Code and referenced standards, except as modified herein.

[BS] A105.2 Alterations and repairs. Alterations and repairs required to meet the provisions of this chapter shall comply with applicable structural requirements of the building code unless specifically provided for in this chapter.

[BS] A105.3 Requirements for plans. The following construction information shall be included in the plans required by this chapter:
1. Dimensioned floor and roof plans showing existing walls and the size and spacing of floor and roof-framing members and sheathing materials. The plans shall indicate all existing URM walls, and new crosswalls and shear walls, and their materials of construction. The location of these walls and their openings shall be fully dimensioned and drawn to scale on the plans.
2. Dimensioned URM wall elevations showing openings, piers, wall classes as defined in Section A106.2.3.9, thickness, heights, wall shear test locations, cracks or damaged portions requiring repairs, the general condition of the mortar joints, and if and where pointing is required. Where the exterior face is veneer, the type of veneer, its thickness and its bonding and/or ties to the structural wall masonry shall be noted.
3. The type of interior wall and ceiling materials, and framing.
4. The extent and type of existing wall anchorage to floors and roof where used in the design.
5. The extent and type of parapet corrections that were previously performed, if any.
6. Repair details, if any, of cracked or damaged unreinforced masonry walls required to resist forces specified in this chapter.
7. All other plans, sections and details necessary to delineate required retrofit construction.
8. The design procedure used shall be stated on both the plans and the permit application.
9. Details of the anchor prequalification program required by Section A107.5.3, if used, including location and results of all tests.
10. Quality assurance requirements of special inspection for all new construction materials and for retrofit construction including: anchor tests, pointing or repointing of mortar joints, installation of adhesive or mechanical anchors, and other elements as deemed necessary to ensure compliance with this chapter.
[BS] A105.4 Structural observation, testing and inspection. Structural observation, in accordance with Section 1704.6 of the Cali- fornia Building Code, shall be required for all structures in which seismic retrofit is being performed in accordance with this chapter. Structural observation shall include visual observation of work for compliance with the approved construction documents and confirmation of existing conditions assumed during design. Structural testing and inspection for new and existing construction materials shall be in accordance with the building code, except as modified by this chapter. Special inspection as described in Section A105.3, Item 10, shall be provided equivalent to Level 3 as prescribed in TMS 402, Table 3.1(2).

SECTION A106—MATERIALS REQUIREMENTS
CEBC § 4.2. High relevance — show source text
[BS] RIGID DIAPHRAGM. A diaphragm of concrete construction or concrete-filled metal deck construction.

[BS] TUCKPOINTING. See “Pointing.”

[BS] UNREINFORCED MASONRY (URM). Includes burned clay, concrete or sand-lime brick; hollow clay or concrete block; plain concrete; and hollow clay tile. These materials shall comply with the requirements of Section A106 as applicable.

[BS] UNREINFORCED MASONRY BEARING WALL. A URM wall that provides the vertical support for the reaction of floor or roof-framing members for which the total superimposed vertical load exceeds 100 pounds per linear foot (1459 N/m) of wall length.

[BS] UNREINFORCED MASONRY WALL. A masonry wall that relies on the tensile strength of masonry units, mortar and grout in resisting design loads, and in which the area of reinforcement is less than the minimum amounts as defined for reinforced masonry walls.

[BS] YIELD STORY DRIFT. The lateral displacement of one level relative to the level above or below at which yield stress is first developed in a frame member.

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APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS

SECTION A104—SYMBOLS AND NOTATIONS

[BS] A104.1 Symbols and notations. For the purpose of this chapter, the following notations supplement the applicable symbols and notations in the building code.

a n = Diameter of core multiplied by its length or the area of the side of a square prism. A = Cross-sectional area of unreinforced masonry pier or wall, square inches (10 [-6] m [2] ). A b = Total area of the bed joints above and below the test specimen for each in-place shear test, square inches (10 [-6] m [2] ). A n = Area of net mortared or grouted section of a wall or wall pier. D = In-plane width dimension of pier, inches (10 [-3] m), or depth of diaphragm, feet (m).

DCR = Demand-capacity ratio specified in Section A111.4.2.

f ′ m = Lower bound masonry compressive strength. f sp = Splitting-tensile strength of masonry. F wx = Force applied to a wall at level x, pounds (N). H = Least clear height of opening on either side of a pier, inches (10 [-3] m).

h/t = Height-to-thickness ratio of URM wall. Height, h, is measured between wall anchorage levels and/or slab-on-grade.

L = Span of diaphragm between shear walls, or span between shear wall and open front, feet (m). L c = Length of crosswall, feet (m). L i = Effective diaphragm span for an open-front building specified in Section A111.8, feet (m). P = Applied force as determined by standard test method of ASTM C496 or ASTM E519, pounds (N).

P D = Superimposed dead load at the location under consideration, pounds (N). For determination of the rocking shear capacity, dead load at the top of the pier under consideration shall be used.
California Existing Building Code High relevance — show source text
8**|** 10**|** 12**|** 8**|** 10**|** 12**| |Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction|Conventional light-frame construction| |1-story|1,100 plf|D|4|4|4|4|4|4|4|4|4|4|4|4|4|4|4|4|4|4| |1-story|1,100 plf|W|13|15|17|13|15|17|13|15|17|13|15|17|13|15|17|13|15|17| |2-story|1,800 plf|D|6|4|4|4|4|4|4|4|4|4|4|4|4|4|4|4|4|4| |2-story|1,800 plf|W|15|15|17|13|15|17|13|15|17|13|15|17|13|15|17|13|15|17| |3-story|2,900 plf|D|14|12|10|9|7|5|6|4|4|4|4|4|4|4|4|4|4|4| |3-story|2,900 plf|W|25|24|24|19|19|18|15|15|17|13|15|17|13|15|17|13|15|17| |4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|4-inch brick veneer over light-frame or 8-inch hollow concrete masonry|**4-inch brick veneer over light-frame
CEBC § 3.2.1. High relevance — show source text
where:

w = As defined in Section 1616 A .3.2.1.

β T = A coefficient with a value of 16,000 pounds (7200 kN) for structures with masonry bearing walls and a value of 4,000 pounds (1300 kN) for structures with bearing walls of cold-formed steel light-frame construction.

1616 A .3.2.4 Vertical ties. Vertical ties shall consist of continuous or spliced reinforcing, continuous or spliced members, wall sheathing or other engineered systems. Vertical tension ties shall be provided in bearing walls and shall be continuous over the height of the building. The minimum nominal tensile strength for vertical ties within a bearing wall shall be equal to the weight of the wall within that story plus the weight of the diaphragm tributary to the wall in the story below. Not fewer than two ties shall be provided for each wall. The strength of each tie need not exceed 3,000 pounds per foot (450 kN/m) of wall tributary to the tie for walls of masonry construction or 750 pounds per foot (140 kN/m) of wall tributary to the tie for walls of cold-formed steel light-frame construction.

SECTION 1617A—MODIFICATIONS TO ASCE 7

1617A.1 General. The text of ASCE 7 shall be modified as indicated in Sections 1617A.1.1 through 1617A.1.41.

1617A.1.1 ASCE 7, Section 1.3. Modify ASCE 7, Section 1.3 by adding Section 1.3.8 as follows:

1.3.8 Structural design criteria. Where design is based on ASCE 7, Chapters 16, 17, 18 or 31, the seismic ground motion, wind tunnel test-based design recommendations, analysis and design methods, material assumptions, testing requirements and acceptance criteria shall be submitted to the enforcement agency as an alternative system.

[DSA-SS] Peer review requirements in Section 322 of the California Existing Building Code shall apply to design reviews required by ASCE 7, Chapters 17, 18, 31 and ASCE 49.

[OSHPD 1 & 4] Peer review requirements in Section 1617A.1.41 of this code shall apply to design reviews required by ASCE 7, Chap- ters 17 and 18.

1617A.1.2 ASCE 7, Section 11.1.3. Replace last paragraph of ASCE 7, Section 11.1.3, by the following:

Non-building structures similar to buildings shall be designed and detailed in accordance with Chapter 12.

1617A.1.3 Reserved.

1617A.1.4 ASCE 7, Table 12.2-1. Modify ASCE 7, Table 12.2-1 as follows:

A. BEARING WALL SYSTEMS

6. Intermediate Precast Shear Walls —Not permitted by OSHPD.

18 . Light-framed walls with shear panels of all other materials —Not permitted by OSHPD and DSA-SS.

B. BUILDING FRAME SYSTEMS
1. Steel ordinary concentrically braced frames— Not permitted by OSHPD.
CBC § A111.3 High relevance — show source text
[BS] COLLAR JOINT. The vertical space between adjacent wythes. A collar joint may contain mortar or grout.

[BS] CROSSWALL. A new or existing wall that meets the requirements of Section A111.3. A crosswall is not a shear wall.

[BS] CROSSWALL SHEAR CAPACITY. The unit shear value times the length of the crosswall, ν c L c .

[BS] DETAILED BUILDING SYSTEM ELEMENTS. The localized elements and the interconnections of these elements that define the design of the building.

[BS] DIAPHRAGM EDGE. The intersection of the horizontal diaphragm and a shear wall.

[BS] DIAPHRAGM SHEAR CAPACITY. The unit shear value times the depth of the diaphragm, ν u D .

[BS] FLEXIBLE DIAPHRAGM. A diaphragm of wood or untopped metal deck construction in which the horizontal deformation along its length is at least two times the average story drift.

HEAD JOINT. The vertical mortar joint placed between masonry units within the wythe.

[BS] NORMAL WALL. A wall perpendicular to the direction of seismic forces.

[BS] OPEN FRONT. An exterior building wall line on one side only without vertical elements of the seismic force-resisting system in one or more stories.

[BS] POINTING. The process of removal of deteriorated mortar from between masonry units and placement of new mortar. Also known as repointing or tuckpointing for purposes of this chapter.

[BS] REPOINTING. See “Pointing.”

[BS] RIGID DIAPHRAGM. A diaphragm of concrete construction or concrete-filled metal deck construction.

[BS] TUCKPOINTING. See “Pointing.”

[BS] UNREINFORCED MASONRY (URM). Includes burned clay, concrete or sand-lime brick; hollow clay or concrete block; plain concrete; and hollow clay tile. These materials shall comply with the requirements of Section A106 as applicable.

[BS] UNREINFORCED MASONRY BEARING WALL. A URM wall that provides the vertical support for the reaction of floor or roof-framing members for which the total superimposed vertical load exceeds 100 pounds per linear foot (1459 N/m) of wall length.

[BS] UNREINFORCED MASONRY WALL. A masonry wall that relies on the tensile strength of masonry units, mortar and grout in resisting design loads, and in which the area of reinforcement is less than the minimum amounts as defined for reinforced masonry walls.

[BS] YIELD STORY DRIFT. The lateral displacement of one level relative to the level above or below at which yield stress is first developed in a frame member.

APPENDIX A-4 2025 CALIFORNIA EXISTING BUILDING CODE

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

APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS

SECTION A104—SYMBOLS AND NOTATIONS

[BS] A104.1 Symbols and notations. For the purpose of this chapter, the following notations supplement the applicable symbols and notations in the building code.
CEBC § 722.3.2.4 High relevance — show source text
Exception: For exterior walls with a fire separation distance greater than 5 feet (1524 mm), the fire shall be assumed to occur on the interior side only.

722.3.2.4 Minimum concrete masonry fire-resistance rating. Where the finish applied to a concrete masonry wall contributes to its fire-resistance rating, the masonry alone shall provide not less than one-half the total required fire-resistance rating.

722.3.2.5 Attachment of finishes. Installation of finishes shall be as follows:
1. Gypsum wallboard and gypsum lath applied to concrete masonry or concrete walls shall be secured to wood or steel furring members spaced not more than 16 inches (406 mm) on center (o.c.).
2. Gypsum wallboard shall be installed with the long dimension parallel to the furring members and shall have all joints finished.
3. Other aspects of the installation of finishes shall comply with the applicable provisions of Chapters 7 and 25.
722.3.3 Multiwythe masonry walls. The fire-resistance rating of wall assemblies constructed of multiple wythes of masonry materials shall be permitted to be based on the fire-resistance rating period of each wythe and the continuous airspace between each wythe in accordance with the following formula: Equation 7-7 R A = ( R 10.59 + R 20.59 + ... + R n 0.59 + A 1 + A 2 + ... + A n ) 1.7

where:

R A = F ire-resistance rating of the assembly (hours).

R 1, R 2, ..., R n = Fire-resistance rating of wythes for 1, 2, n (hours), respectively. A 1, A 2, ..., A n = 0.30, factor for each continuous airspace for 1, 2, ... n, respectively, having a depth of [1] / 2 inch (12.7 mm) or more between wythes.

722.3.4 Concrete masonry lintels. Fire-resistance ratings for concrete masonry lintels shall be determined based on the nominal thickness of the lintel and the minimum thickness of concrete masonry or concrete, or any combination thereof, covering the main reinforcing bars, as determined in accordance with Table 722.3.4, or by approved alternate methods.

Frequently asked questions

Do Appendix A chapters apply to all buildings with those materials?

No. Appendix A chapters are a compliance option in the CEBC but are explicitly mapped for use with buildings assigned to Risk Category I or II; check § 304.3.2 and agency adoption under § A100.1. file

How do I know if a masonry wall is a "bearing" wall under Appendix A?

If the wall is URM and the superimposed vertical load it supports exceeds 100 plf, it is an Unreinforced Masonry Bearing Wall under the Appendix definitions (see § A103).

My building is RC with plywood diaphragms — can I use Chapter A2?

Chapter A2 is intended for reinforced concrete or reinforced masonry wall buildings with flexible diaphragms. You must confirm the diaphragm classification (flexible vs rigid) per the Appendix definitions before selecting A2. See § A202 and Appendix definitions. file

If my jurisdiction adopted Appendix A partially, does that matter?

Yes. State or local adoption can limit which sections are enforceable. Check the adoption/vesting language in § A100.1 and the Appendix A adoption matrix. file

What plan content and inspections does Appendix A require if I use it?

Appendix A requires dimensioned plans showing existing URM walls, wall classes, anchor test locations, and repair details (see § A105.3), plus structural observation and special inspection for retrofit work (see § A105.4).

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Retrofit design procedures, ASCE 41 modifications, and Appendix A guidance

California Existing Building Code