CEBC · California Existing Building Code
Appendix A & C — seismic and wind retrofit guidelines (practical lookups)
Appendix A and C in the CEBC provide practical prescriptive guidelines for seismic and wind retrofits—see §A101/§A105 and §C101/§C104 for fast lookups.
Last reviewed: July 6, 2026
Overview
Appendix A contains the CEBC's guidelines for seismic retrofit of existing buildings, organized by building type (for example: unreinforced masonry, reinforced concrete/masonry walls, and light‑frame wood buildings) and including prescriptive and referenced‑standard options to upgrade lateral resistance. See the Appendix A table of contents and chapter entries, including §A101 (Purpose) and the general requirements in §A105, for quick orientation.
Appendix C provides voluntary, prescriptive wind‑retrofit measures targeted at high‑wind vulnerabilities — notably gable‑end framing and roof‑deck attachments. Chapter C1 (see §C101) sets eligibility and intent; Chapter C1 §C104 contains the practical retrofit methods, figures, fastening schedules and retrofit configurations for gable ends, and Chapter C2 (§C201–§C202) covers roof‑deck fastening. These sections are written for fast lookups and field application.
Both appendices are intended as practical supplements to the CEBC compliance paths: use them for prescriptive fixes, voluntary mitigations, or as starting points before triggering more detailed evaluation (for example when ASCE 41 procedures are required by Chapter 317). For the wind appendix note that the provisions are not mandatory unless adopted by the enforcing authority.
In this section
Code references
Grounded in the retrieved California Existing Building Code — click a citation to read the verbatim passage:
CEBC § 102.4 High relevance — show source text
Chapter 14 is applicable to any building that is moved or relocated. This chapter is independent of any of the three compliance methods and focuses on the structural loads where the building is being relocated.
Chapter 15 Construction Safeguards.
Chapter 15 establishes specific regulations in order to minimize the risk to the public and adjacent property during construction. Additionally, this chapter addresses fire and life safety and means of egress during the construction process. This includes requirements for a site safety plan. This chapter is also consistent with Chapter 33 of the CBC and Chapter 33 of the California Fire Code (CFC).
Chapter 16 Referenced Standards.
Chapter 16 lists all of the product and installation standards and codes that are referenced throughout Chapters 1 through 15 and includes identification of the promulgators and the section numbers in which the standards and codes are referenced. As stated in Section 102.4, these standards and codes become an enforceable part of the code (to the prescribed extent of the reference) as if printed in the body of the code.
Appendix A Guidelines for the Seismic Retrofit of Existing Buildings.
Appendix A provides guidelines for upgrading the seismic resistance capacity of different types of existing buildings. It is organized into separate chapters which deal with buildings of different types, including unreinforced masonry buildings, reinforced concrete and reinforced masonry wall buildings, and lightframe wood buildings. This appendix includes its own referenced standards.
Appendix B Supplementary Accessibility Requirements for Existing Buildings and Facilities.
Chapters 11A and 11B of the CBC contain provisions that set forth requirements for accessibility to buildings and their associated sites and facilities for people with physical disabilities. Appendix B was added to address accessibility in construction for items that are not typically enforceable through the traditional building code enforcement process.
Appendix C Guidelines for the Wind Retrofit of Existing Buildings.
The purpose of Appendix C is to provide voluntary prescriptive alternatives for addressing the retrofit of buildings in high-wind areas. Currently, there are two chapters which deal with the retrofit of gable ends and the fastening of roof decks, Appendix Chapters C1 and C2, respectively. This appendix includes its own referenced standards.
Appendix D Board of Appeals.
Appendix D contains the provisions for appeal and the establishment of a board of appeals. The provisions include the application for an appeal, the makeup of the board of appeals and the conduct of the appeal process.
Appendix E Temporary Emergency Uses.
Appendix E is intended to provide guidance for designers, engineers, architects and fire and building officials on allowing temporary emergency uses of existing buildings with respect to the minimum code requirements. This appendix is a template or checklist that references the relevant code requirement of concerns.
Resource A Guidelines on Fire Ratings of Archaic Materials and Assemblies.
In the process of repair and alteration of existing buildings, based on the nature and the extent of the work, the CEBC might require certain upgrades in the fire-resistance rating of building elements, at which time it becomes critical for the designers and the code
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officials to be able to determine the fire-resistance rating of the existing building elements as part of the overall evaluation for the assessment of the need for improvements. These guidelines are based upon the Guideline on Fire Ratings of Archaic Materials published by the National Institute of Building Sciences (NIBS).
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CEBC § 25.4 High relevance — show source text
BENT TO ‘L’ SHAPE AND SECURED TO BACK OF RETR
MINIMUM THICKNESS 20 GAUGE FASTENED WITH MINIMUM 6 EA
MINIMUM THICKNESS 20 GAUGE FASTENED WITH MINIMUM 9 EA
MINIMUM THICKNESS 18 GAUGE FASTENED WITH MINIMUM 12 E
MINIMUM THICKNESS 18 GAUGE FASTENED WITH MINIMUM 8 EA
COMPRESSION BLOCK, MINIMUM 2X4. COMPRESSION B
SECURED TO HORIZONTAL BRACE WITH MINIMUM 6
SECURED TO HORIZONTAL BRACE WITH MINIMUM 8
SECURED TO HORIZONTAL BRACE WITH MINIMUM 10
SECURED TO HORIZONTAL BRACE WITH MINIMUM 12
HORIZONTAL BRACE, MINIMUM 2X4 SECURE
1 HORIZONTAL BRACE FOR RETROFIT CO
2 HORIZONTAL BRACES FOR RETROFIT C
ATTIC FRA|||||| ||||||| |WALL BELOW|WALL BELOW|WALL BELOW||||FASTENERS SHALL NOT BE PLACED CLOSER TO ENDS OF LUMBER THAN 2FASTENERS SHALL NOT BE PLACED CLOSER TO EDGES OF LUMBER THAN [1][1] // 22 ″.″ EXCEPT WHERE STRAPS DICTATE OTHERWISE. THE NUMBER OF FASTENERS SHOWN IS NOT NECESSARILY THE NUMBER REQUIRED.
PLAN VIEWS
RETROFIT CONFIGURATIONS A, B AND C
For SI: 1 inch = 25.4 mm.
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APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
[BS] FIGURE C104.2(2)—CONVENTIONALLY FRAMED GABLE END L-BENT STRAP
For SI: 1 inch = 25.4 mm.
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APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
[BS] FIGURE C104.2(3)—TRUSS FRAMED GABLE END U-BENT STRAP
For SI: 1 inch = 25.4 mm.
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APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
[BS] FIGURE C104.2(4)—CONVENTIONALLY FRAMED GABLE END U-BENT STRAP
For SI: 1 inch = 25.4 mm.
[BS] C104.2.1 Existing gable end studs. If the spacing of existing vertical gable end studs is greater than 24 inches (64 mm), a new stud and corresponding horizontal braces shall be installed such that the maximum spacing between existing and added studs shall be not greater than 24 inches (64 mm). Additional gable end wall studs shall not be required at locations where their length would be 3 feet (914 mm) or less.
CEBC § 1.11. High relevance — show source text
Adopting Agency BSC BSC-
CGSFM HCD Col6 Col7 DSA Col9 Col10 OSHPD Col12 Col13 Col14 Col15 Col16 Col17 BSCC DPH AGR DWR CEC CA SL SLC Adopting Agency BSC BSC-
CGSFM 1 2 1/AC AC SS SS/CC 1 1R 2 3 4 5 6 6 6 6 6 6 6 6 6 Adopt Entire Chapter Adopt Entire Chapter as
amended (amended
sections listed below)Adopt only those sections
that are listed belowChapter / Section 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.
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C GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
The provisions contained in this appendix are not mandatory unless specifically referenced in the adopting ordinance.
User notes:
About this appendix: Appendix C is intended to provide guidance for retrofitting existing structures to strengthen their resistance to wind forces. This appendix is similar in scope to Appendix A, which addresses seismic retrofits for existing buildings, except that the subject matter is related to wind retrofits. These retrofits are voluntary measures that serve to better protect the public and reduce damage from high-wind events for existing buildings.
The purpose of this appendix is to provide prescriptive alternatives for addressing retrofit of buildings in high-wind areas. Currently there are two chapters that deal with the retrofit of gable ends and the fastening of roof decks, Appendix Chapters C1 and C2, respectively.
ICC code development note: Code change proposals to this appendix will be considered by the IBC—Structural Code Development Committee during the
2025 (Group B) Code Development Cycle.
CHAPTER C1 GABLE END RETROFIT FOR HIGH-WIND AREAS
SECTION C101—GENERAL
CEBC § 1.11. High relevance — show source text
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.
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C GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
The provisions contained in this appendix are not mandatory unless specifically referenced in the adopting ordinance.
User notes:
About this appendix: Appendix C is intended to provide guidance for retrofitting existing structures to strengthen their resistance to wind forces. This appendix is similar in scope to Appendix A, which addresses seismic retrofits for existing buildings, except that the subject matter is related to wind retrofits. These retrofits are voluntary measures that serve to better protect the public and reduce damage from high-wind events for existing buildings.
The purpose of this appendix is to provide prescriptive alternatives for addressing retrofit of buildings in high-wind areas. Currently there are two chapters that deal with the retrofit of gable ends and the fastening of roof decks, Appendix Chapters C1 and C2, respectively.
ICC code development note: Code change proposals to this appendix will be considered by the IBC—Structural Code Development Committee during the
2025 (Group B) Code Development Cycle.
CHAPTER C1 GABLE END RETROFIT FOR HIGH-WIND AREAS
SECTION C101—GENERAL
[BS] C101.1 Purpose. This chapter provides prescriptive methods for partial structural retrofit of an existing building to increase its resistance to out-of-plane wind loads. It is intended for voluntary use and for reference by mitigation programs. The provisions of this chapter do not necessarily satisfy requirements for new construction. Unless specifically cited, the provisions of this chapter do not necessarily satisfy requirements for structural improvements triggered by addition, alteration, repair, change of occupancy, building relocation or other circumstances.
[BS] C101.2 Eligible buildings and gable end walls. The provisions of this chapter are applicable only to buildings that meet the following eligibility requirements:
- The building is not more than three stories tall, from adjacent grade to the bottom plate of each gable end wall being retrofitted with this chapter.
- The building is classified as Occupancy Group R3 or is within the scope of the California Residential Code .
- The structure includes one or more wood-framed gable end walls, either conventionally framed or metal-plate-connected.
In addition, the provisions of this chapter are applicable only to gable end walls that meet the following eligibility requirements:
- Each gable end wall has or shall be provided with studs or vertical webs spaced 24 inches (610 mm) on center maximum.
- Each gable end wall has a maximum height of 16 feet (4877 mm).
[BS] C101.3 Compliance Eligible gable end walls in eligible buildings may be retrofitted in accordance with this chapter. Other modifications required for compliance with this chapter shall be designed and constructed in accordance with the California Building Code or California Residential Code provisions for new construction, except as specifically provided for by this chapter.
SECTION C102—DEFINITIONS
CEBC § 2.7 High relevance — show source text
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APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
[BS] FIGURE C104.2.7—DETAIL OF RETROFIT TIE INSTALLATION
WHEN ADDITIONAL SUPPORTS ARE NEEDED FOR HORIZONTAL BRACE NEAR RIDGE, MIN. 2x4 RAFTER TIE, ATTACH TO EACH INTERSECTING MEMBER
REQUIRED 2x RETROFIT STUD, ATTACH TO EXISTING STUD IN ACCORDANCE WITH SECTION C104.2.7
FLAT 2x4 HORIZONTAL BRACES
Col1 Col2 Col3 Col4 Col5 INSTALL 2x4 COMPRESSION BLOCK (TIGHT FIT) BETWEEN CENTER EXISTING GABLE END STUD OR RETROFIT STUD (TOP AND BOTTOM)
2x4 COMPRESSION BLOCK OF REQUIRED LENGTH, ATTACH TO HORIZONTAL BRACE W/ REQUIRED NUMBER OF 3″ LONG FASTENERS
CENTER FLAT 2x4 HORIZONTAL BRACES @ SIDE OF CENTER EXISTING GABLE END
STUD AND LINE WITH RETROFIT STUD
ELEVATION VIEW
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
[BS] C104.2.8 Interrupted horizontal braces. Where conditions exist that prevent the installation of a continuous horizontal brace then horizontal braces shall be permitted to be interrupted using the methods shown in Figures C104.2.8(1), C104.2.8(2), and C104.2.8(3). For interruptions that occur in the attic framing space closest to the gable end, nine 3-inch (76 mm) fasteners shall be used to connect each section of the interrupted horizontal braces. For interruptions that occur in the second attic space from the gable end, six 3-inch (76 mm) fasteners shall be used to connect each section of the interrupted horizontal braces. For interruptions that occur in the attic framing space farthest from the gable end, three 3-inch (76 mm) fasteners shall be used to connect each section of the interrupted horizontal braces. Horizontal braces shall be continued far enough to allow connections to three existing roof framing members as shown in Figure C104.2.8(1), C104.2.8(2) or C104.2.8(3). Fasteners shall be spaced in accordance with Section C103.5.3. Horizontal braces shall be the same width and depth as required for an uninterrupted member.
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APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
[BS] FIGURE C104.2.8(1)—SPLICED HORIZONTAL BRACES
For SI: 1 inch = 25.4 mm.
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APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
CBC § 2025 High relevance — show source text
A403 Analysis and Design. . . . . . . . . . . . . . . . . . APPENDIX A-45
A404 Prescriptive Measures for Weak Story. . APPENDIX A-47
A405 Materials of Construction . . . . . . . . . . . . APPENDIX A-48
A406 Construction Documents. . . . . . . . . . . . . APPENDIX A-48
A407 Quality Control. . . . . . . . . . . . . . . . . . . . . . APPENDIX A-49
CHAPTER A5 REFERENCED STANDARDS . . . . APPENDIX A-53
A501 Referenced Standards . . . . . . . . . . . . . . . APPENDIX A-53
APPENDIX B SUPPLEMENTARY ACCESSIBILITY
REQUIREMENTS FOR EXISTING BUILDINGS
AND FACILITIES. . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX B-3
B101 Qualified Historic Buildings and Facilities. . . . . . . . . . . . . . . . . . . . . . . APPENDIX B-3
B102 Fixed Transportation Facilities and Stations . . . . . . . . . . . . . . . . . . . . . . . APPENDIX B-3
B103 Dwelling Units and Sleeping Units. . . . . . APPENDIX B-4
B104 Referenced Standards . . . . . . . . . . . . . . . . APPENDIX B-4
APPENDIX C GUIDELINES FOR THE WIND RETROFIT
OF EXISTING BUILDINGS . . . . . . . . . . . . . . . . . APPENDIX C-3
CHAPTER C1 GABLE END RETROFIT FOR
HIGH-WIND AREAS . . . . . . . . . . . . . . . . . . . . . . APPENDIX C-3
C101 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX C-3
C102 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX C-3
C103 Materials of Construction . . . . . . . . . . . . . APPENDIX C-4
C104 Retrofitting Gable End Walls to Enhance Wind Resistance . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX C-5
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CONTENTS
CHAPTER C2 ROOF DECK FASTENING FOR
HIGH-WIND AREAS . . . . . . . . . . . . . . . . . . . . . APPENDIX C-27
C201 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX C-27
C202 Roof Deck Attachment for
Wood Roofs. . . . . . . . . . . . . . . . . . . . . . . APPENDIX C-27
CEBC § 2.8 High relevance — show source text
For interruptions that occur in the attic framing space closest to the gable end, nine 3-inch (76 mm) fasteners shall be used to connect each section of the interrupted horizontal braces. For interruptions that occur in the second attic space from the gable end, six 3-inch (76 mm) fasteners shall be used to connect each section of the interrupted horizontal braces. For interruptions that occur in the attic framing space farthest from the gable end, three 3-inch (76 mm) fasteners shall be used to connect each section of the interrupted horizontal braces. Horizontal braces shall be continued far enough to allow connections to three existing roof framing members as shown in Figure C104.2.8(1), C104.2.8(2) or C104.2.8(3). Fasteners shall be spaced in accordance with Section C103.5.3. Horizontal braces shall be the same width and depth as required for an uninterrupted member.
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APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
[BS] FIGURE C104.2.8(1)—SPLICED HORIZONTAL BRACES
For SI: 1 inch = 25.4 mm.
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APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
[BS] FIGURE C104.2.8(2)—SPLICED HORIZONTAL BRACES
For SI: 1 inch = 25.4 mm.
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APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
[BS] FIGURE C104.2.8(3)—SPLICED HORIZONTAL BRACES
For SI: 1 inch = 25.4 mm.
[BS] C104.2.9 Piggyback gable end frames. Piggyback gable end frames (gable end frames built in two sections one above the other) shall be permitted to be retrofitted if either of the following cases is true:
- The existing studs in both the upper gable end frames and the lower gable end frames to which wall sheathing, panel siding, or other wall covering are attached are sufficiently in line that retrofit studs can be installed and connections made between the two with retrofit stud(s).
- Existing studs in the upper frame are not sufficiently in line with the studs in the frame below and the existing studs in the upper frame are 3 feet (91 cm) or shorter.
CEBC § 317.3.2 High relevance — show source text
2. There are changes in risk category. 3. The modification to the structural components increases the seismic forces in or strength requirements of any structural component of the existing structure by more than 10 percent cumulative since the original construction, unless the component has the capacity to resist the increased forces determined in accordance with Section 319. If the building’s seismic base shear capacity has been increased since the original construction, the percent change in base shear may be calculated relative to the increased value.
4. Structural elements need repair where the damage has reduced the lateral-load-resisting capacity of the structural system by more than 10 percent. 5. Changes in live or dead load increase story shear by more than 10 percent.
317.3.2 Public school buildings. [DSA-SS] For public schools, the provisions of Section 317 apply when required in accordance with Sections 4-307 and 4-309(c) of the California Administrative Code.
317.3.3 Community college buildings. [DSA-SS/CC] For community colleges, the provisions of Section 317 apply when required in accordance with Sections 4-307 and 4-309(c) of the California Administrative Code.
317.4 Evaluation required. If the criteria in Section 317.3 apply to the project under consideration, the design professional of record shall provide an evaluation in accordance with Section 317 to determine the seismic performance of the building in its current configuration and condition. If the structure's seismic performance as required by Section 317.5 is evaluated as satisfactory and the peer reviewer(s), when Method B of Section 321 is used, concur, then no structural retrofit is required.
317.5 Minimum seismic design performance levels for structural and nonstructural components. Following the notations of ASCE 41, the seismic requirements for design and assessment are based upon a prescribed Seismic Hazard Level (BSE-1N, BSE-2N, BSE-1E, BSE-R or BSE-C), a specified structural performance level (S-1 through S-5) and a nonstructural performance level (N-A through N-E). The minimum seismic performance criteria are given in Table 317.5 according to the Building Regulatory Authority and the Risk Category as determined in Chapter 16 of the California Building Code or by the regulatory authority. The building shall be evaluated in accordance with a Tier 3 Systematic Evaluation and Retrofit per ASCE 41 Chapter 6 for both the Level 1 and Level 2 performance levels, and the more restrictive requirements shall apply.
Exception: If the floor area of an addition is greater than the larger of 50 percent of the floor area of the original building or 1,000 square feet (93 m [2] ), then the Table 317.5 entries for BSE-R (or BSE-1E) and BSE-C are replaced by BSE-1N and BSE-2N, respectively.
|TABLE 317.5—SEISMIC PERFORMANCE REQUIREMENTS2,
CEBC § 1.10.1 High relevance — show source text
CHAPTER TOPICS Col2 CHAPTER SUBJECTS 1, 2 Administrative Requirements and Definitions 3 Provisions for all Compliance Methods 4 Repairs 5 Prescriptive Compliance Method for Existing Buildings 6–11 Work Area Compliance Method for Existing Buildings 13 Performance Compliance Method for Existing Buildings 14 Relocated Buildings 15 Construction Safeguards 16 Referenced Standards Appendix A Guidelines for Seismic Retrofit of Existing Buildings Appendix B Supplementary Accessibility Requirements for Existing Buildings Appendix C Guidelines for Wind Retrofit of Existing Buildings Appendix D Board of Appeals Appendix E Temporary Emergency Uses Resource A Guidelines on Fire Ratings of Archaic Materials and Assemblies CALIFORNIA BUILDING CODE CORRELATED TOPICS
The CEBC requirements for construction safeguards are directly correlated to the requirements of the CBC. The following table shows chapters of the CBC that are correlated with the CEBC:
CEBC/CBC CORRELATED TOPICS Col2 Col3 CEBC CHAPTER/SECTION CBC CHAPTER/SECTION SUBJECT Chapter 15 Chapter 33 Construction safeguards Chapter 1 Scope and Administration.
Chapter 1 establishes the limits of applicability of the code and describes how the code is to be applied and enforced. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the design professional, contractor and property owner.
Chapter 2 Definitions.
Chapter 2 is the repository of the definitions of terms used in the body of the code. The user of the code should be familiar with and consult this chapter because the definitions are essential to the correct interpretation of the code and because the user may not be aware that a term is defined.
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Chapter 3 Provisions for All Compliance Methods.
Chapter 3 guides the use of the three compliance methods of the CEBC and provides requirements that apply globally. The globally applicable requirement include general requirements related to buildings materials and other applicable codes, storm shelters, structural loads, in-situ load tests, accessibility, smoke alarms, carbon monoxide detection and exterior wall coverings.
Chapter 3A Provisions for All Compliance Methods.
Chapter 3A controls the compliance options for alteration, repair, addition, evaluation and change of occupancy of existing structures regulated by the Department of Health Care Access and Information/Office of Statewide Hospital Planning and Development, which include hospitals and correctional treatment centers (applications listed in Sections 1.10.1 (OSHPD 1).
Chapter 4 Repairs.
Chapter 4, a chapter independent of the three compliance methods, governs the repair of existing buildings. The provisions define conditions under which repairs may be made using materials and methods like those of the original construction or the extent to which repairs must comply with requirements for new buildings.
Chapter 4A Repairs.
Chapter 4A governs the repair of existing buildings regulated by the Department of Health Care Access and Information/Office of State- wide Hospital Planning and Development, which include hospitals and correctional treatment centers (applications listed in Sections 1.10.1 (OSHPD 1).
CEBC § 0.35 High relevance — show source text
RSRS is a Roof Sheathing Ring Shank nail meeting the specifications in ASTM F1667.
e. Tabulated fastener requirements apply where the basic wind speed,V, is less than 140 mph. For wood structural panel roof sheathing attached to gable-end roof framing and
to intermediate supports within 48 inches of roof edges and ridges, nails shall be spaced at 4 inches on center where the basic wind speed,V, is greater than 130 mph in Expo-
sure B or greater than 110 mph in Exposure C. Spacing exceeding 6 inches on center at intermediate supports shall be permitted where the fastening is designed per the AWC
NDS. Where the specific gravity of the wood species used for roof framing is greater than or equal to 0.35 but less than 0.42 in accordance with AWC NDS, fastening of roof
sheathing shall be with RSRS-03 (21/2″ × 0.131″ × 0.281″ head) nails unless alternative fastening is designed in accordance with AWC NDS. Where the specific gravity of the wood
species used for roof framing is less than 0.35, fastening of the roof sheathing shall be designed in accordance with AWC NDS.
f. Fastening is only permitted where the basic wind speed,V, is less than or equal to 110 mph and where fastening is to wood framing of a species with specific gravity greater
than or equal to 0.42 in accordance with AWC NDS.
g. Nails and staples are carbon steel meeting the specifications of ASTM F1667. Connections using nails and staples of other materials, such as stainless steel, shall be designed
by acceptable engineering practice or approved under Section 104.2.3.|For SI: 1 inch = 25.4 mm.
a. Nails spaced at 6 inches at intermediate supports where spans are 48 inches or more. For nailing of wood structural panel and particleboard diaphragms and shear walls, refer
to Section 2305. Nails for wall sheathing are permitted to be common, box or casing.
b. Spacing shall be 6 inches on center on the edges and 12 inches on center at intermediate supports for nonstructural applications. Panel supports at 16 inches (20 inches if
strength axis in the long direction of the panel, unless otherwise marked).
c. Where a rafter is fastened to an adjacent parallel ceiling joist in accordance with this schedule and the ceiling joist is fastened to the top plate in accordance with this schedule,
the number of toenails in the rafter shall be permitted to be reduced by one nail.
d. RSRS is a Roof Sheathing Ring Shank nail meeting the specifications in ASTM F1667.
e. Tabulated fastener requirements apply where the basic wind speed,V, is less than 140 mph. For wood structural panel roof sheathing attached to gable-end roof framing and
to intermediate supports within 48 inches of roof edges and ridges, nails shall be spaced at 4 inches on center where the basic wind speed,V, is greater than 130 mph in Expo-
sure B or greater than 110 mph in Exposure C. Spacing exceeding 6 inches on center at intermediate supports shall be permitted where the fastening is designed per the AWC
NDS.CEBC § 1402.6 Medium relevance — show source text
1402.6
Glass 402.1, 406, 804.7.1, 804.7.2, 1011.8.2, 1305.2.10.1, Resource A Gravity Loads (see Structural Loads/Forces) Guards 802.5, 802.5.1, 802.5.2, 804.12, 804.12.1, 804.12.2 Guidelines for Structural Retrofit
Seismic Appendix A Wind Appendix C
Handrails 503.1, 804.4, 1011.5.1, 1011.5.4 Hazard Categories 1011.5, Table 1011.5, 1011.6, Table 1011.6, Table 1011.7 Height (see Building, Height) High-Rise Building 1011.6.1, 1305.2.17, 1305.2.19 Historic Building (see Building, Historic)
Incidental Use Areas 1002.2 Inspection 104.7.2, 104.4, 104.7, 105.2, 106.1, 106.3.1, 106.6, 109, 1402.7, A105.3, A105.4, A107.1, A107.4, A113.7, A205.3.1, A205.4, A304.4.3, A304.5, A406.3.4, A407.3 Interior Finishes 702.1, 702.2, 1011.3 Interior Trim 702.3
Live Load (see Structural Loads/Forces) Load-Bearing Element 105.2.2, 202, Resource A
CEBC § 2.1. Medium relevance — show source text
Where wall sheathing, panel siding or other wall covering is fastened to a conventionally framed gable end, retrofit studs shall be applied in accordance with Section C104.2.1.
APPENDIX C-18 2025 CALIFORNIA EXISTING BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
[BS] FIGURE C104.3—METHOD OF INSTALLING RETROFIT STUDS
Col1 Col2 SECTION C104.3.2 SECTION C104.3.3 SECTION C104.3.4 SECTION C104.3.5 SECTION C104.3.6 For SI: 1 inch = 25.4 mm.
[BS] C104.3.1 Fastening. Where nail plates are not used, retrofit studs shall be attached to existing studs using 3-inch (76 mm) fasteners at not greater than 6 inches (152 mm) on center but not closer than 2 [1] / 2 inches (64 mm) on center with fasteners not closer to ends of members than 2 [1] / 2 inches (64 mm).
[BS] C104.3.2 Method #1: Face-to-edge or face-to-face method. Retrofit studs shall be installed immediately adjacent to existing gable end wall studs as indicated in Figure C104.3(a). The retrofit studs shall overlap the edge or side of the existing stud by not less than 1 [1] / 4 inches (32 mm). Fasteners shall be installed as specified in Section C104.3.1.
[BS] C104.3.3 Method #2: Face-to-face offset method. Retrofit studs shall be installed against the face of existing studs as indicated in Figure C104.3(b) such that the faces overlap not less than 1 [1] / 2 inches (38 mm) and the edge distance to fasteners is not less than [3] / 4 inch (19.1 mm). Fasteners shall be installed as specified in Section C104.3.1.
2025 CALIFORNIA EXISTING BUILDING CODE APPENDIX C-19
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
APPENDIX C—GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUILDINGS
[BS] C104.3.4 Method #3: Butted retrofit stud method. Provided that all of the following fastening conditions are met, retrofit studs shall be permitted to be butted by their edge to existing studs with the addition of nail plates as indicated in Figure C104.3(c) and Figure C104.3.4.
- The narrow edge of retrofit studs shall be installed against the narrow or the wide face of existing studs.
- Not fewer than two nail plates shall be used.
- Fasteners used to secure nail plates to studs shall be a minimum 1 [1] / 4 inches (32 mm) long (#8 wood screws or 8d nails).
- Fasteners placed in nail plates shall have a minimum end distance of 2 [1] / 2 inches (64 mm) for both studs and a maximum end distance of 6 inches (152 mm) from the ends of the shorter stud.
Frequently asked questions
Are Appendix A and Appendix C mandatory?
No — they are guidance appendices. Appendix C explicitly states its provisions are not mandatory unless referenced by the adopting ordinance; Appendix A likewise provides guidelines and referenced standards to be used as voluntary or supplemental retrofit measures.
Where in the appendices do I find quick prescriptive fixes for gable‑end failure?
Use Appendix C Chapter C1 — see §C101 for scope/eligibility and §C104 for the prescriptive retrofit methods, installation options, figures and fastening schedules for gable‑end studs and horizontal bracing.
When should I move from the appendix guidance to a full engineering evaluation?
If the project triggers CEBC evaluation or alteration thresholds (for example work that affects more than a threshold of the building, seismic performance concerns, or requirements in Chapter 317), a full engineering evaluation or ASCE 41 systematic assessment is appropriate rather than relying solely on appendix prescriptive measures. Check Chapter 317 and related sections for evaluation triggers.
More in California Existing Building Code
- Administration and Definitions (Scope, enforcement, code official duties, definitions)
- Provisions for All Compliance Methods (general requirements that apply to all compliance options; Chapter 3 / 3A)
- Seismic retrofit and evaluation (Appendix A and seismic provisions/sections for evaluation and retrofit)
- Referenced Standards and Appendices (Chapter 16 and Appendices A–E, Resource A)
- Repairs (Chapter 4 — repair-specific rules for materials, means of egress, structural, MEP, etc.)
- Alterations — Level 1, Level 2, Level 3 (technical requirements for each alteration level; Chapters 7–9)
- Change of Occupancy and Additions (requirements for occupancy changes and additions; Chapters 10–11)
- Compliance Methods — Prescriptive, Work Area, Performance (Chapters 5, 6–11, 13)
- Relocated Buildings (requirements for buildings moved or relocated; Chapter 14)
- Construction Safeguards (site safety, means of egress and life-safety during construction; Chapter 15)
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Appendices B, D, E and Resource A — accessibility, appeals, emergency uses and fire ratings
Using Referenced Standards (how they become part of the code)
Chapter 16 — common standards cited and where to find them
Referenced Standards and Appendices (Chapter 16 and Appendices A–E, Resource A)
California Existing Building Code