CEBC · California Existing Building Code
When must a building be retrofitted and can retrofit be deferred?
If an evaluation under CEBC Section 317 finds your building does not meet required seismic performance, you must retrofit it — either as part of the current construction/repairs or by submitting an approved plan to finish the retrofit. Voluntary seismic improvements are allowed only under § 317.11 and the procedures in § 319.12, and state/school projects have specific documentation requirements.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
The owner must retrofit an existing building when an evaluation shows the structure does not meet the required seismic performance objectives — the owner must either perform the retrofit as part of the work (additions/alterations/repairs) or submit a plan, acceptable to the building official, to complete the retrofit in a timely manner (§ 317.6) .
Where an alteration is voluntary (not required by other parts of the chapter), voluntary changes to lateral‑force‑resisting systems are permitted only under the rules for voluntary modifications in § 319.12, and the allowance in § 317.11 ties those voluntary modifications to § 319.12 .
If an evaluation finds the building noncompliant for the seismic performance required by Section 317, the owner must either retrofit now or provide an approved plan to finish the retrofit — you cannot simply defer it without the building official’s acceptance. § 317.6
Requirements in detail
When retrofit is required (plain rule)
- If the building evaluation shows the building does not meet the seismic performance objectives of Section 317, the owner shall take appropriate steps to ensure retrofit is done in accordance with § 317.6. The code gives two acceptable steps:
- Undertake the seismic retrofit as part of the current additions/alterations/repairs; or
- Provide a plan, acceptable to the building official, that shows the retrofit will be completed in a timely manner (§ 317.6) .
- Relocation or moving of an existing building is treated as an alteration, and therefore requires filing plans and specs for approval by the building official (also in § 317.6) .
Voluntary modifications vs. required retrofit
- Voluntary lateral‑force‑resisting system modifications (work done to improve seismic performance that is not required by other code provisions) are permitted under § 317.11, but they must comply with the procedures and limitations of § 319.12 (see below) .
Who decides timing and acceptability?
- The building official must accept the owner’s plan to complete the retrofit in a timely manner; the code does not permit an unspecified indefinite deferral without that acceptance (§ 317.6) .
Decision dimensions (quick reference table)
| Decision question | Key values / triggers | Code reference |
|---|---|---|
| Did the evaluation find the building noncompliant with Section 317 seismic objectives? | If yes → retrofit required (now as part of work or via an approved plan) | § 317.6 |
| Is the change a voluntary improvement (not required by other code provisions)? | Voluntary lateral‑force modifications permitted but subject to § 319.12 procedures | § 317.11 / § 319.12 |
| Can relocation be done without retrofit? | Relocation = alteration; plans/specs must be filed and approved — retrofit requirements apply as for alterations | § 317.6 |
| Documentation requirement for voluntary mods (state-owned / schools) | Design documents must state the seismic requirements of CEBC were NOT checked and that the work is to a different standard (see required phrase) | § 319.12.1.1 |
Exceptions & special cases
- The allowance to do voluntary lateral‑force‑resisting system modifications only applies where the exception in § 317.2 applies; when it does, § 317.11 directs you to the procedural rules in § 319.12 for how voluntary modifications are handled .
- State‑owned buildings and public schools/community colleges have specific notes inside § 319.12: voluntary modifications are permitted (for state‑owned: § 319.12.1) but the approved documents must clearly state the scope and the explicit disclaimer about not meeting the full CEBC retrofit/evaluation requirements (see required wording in § 319.12.1.1) .
- If Section 317.3 (applicability triggers such as cost thresholds, percent changes in forces, damage, etc.) does not require an assessment or retrofit, then only the limited provisions of § 317.11 / § 319.12 may apply (i.e., voluntary work) — consult § 317.2–317.4 for those applicability rules .
Common mistakes
- Assuming “voluntary” equals “no oversight.” Voluntary modifications must still follow the procedures and documentation required by § 319.12, and for state/school projects the design documents must include the specific disclaimer language in § 319.12.1.1 .
- Thinking retrofit can be postponed without approval. § 317.6 requires either doing the retrofit as part of the work or submitting a plan acceptable to the building official — you cannot simply skip or indefinitely defer retrofit without that approved plan .
- Treating building relocation as a “non‑alteration.” The code explicitly treats relocation/moving as an alteration that requires plans and, where evaluation shows noncompliance, retrofit action under § 317.6 .
- Using voluntary retrofit language to avoid a required retrofit: if the evaluation shows noncompliance with Section 317, the retrofit requirement under § 317.6 applies regardless of whether the owner prefers to call the work “voluntary” .
Worked example — concrete scenario
Scenario: A university (state‑owned) plans an addition that increases the seismic demand on several existing frames. The cumulative increase in seismic force on a particular structural component since original construction is calculated at 12%.
- Applicability check: Section 317.3 identifies a change in seismic forces greater than 10% as an applicability trigger for evaluation under Section 317 (see the list of triggers in § 317.3) . Because the change is 12% (>10%), the project must follow Section 317 evaluation procedures.
- Evaluation outcome: A registered design professional evaluates the existing building and determines it does not meet the required seismic performance objectives. Under § 317.6, the owner must either:
- Perform the seismic retrofit as part of the alteration/construction now, or
- Submit a retrofit completion plan that is acceptable to the building official showing how and when the retrofit will be completed (§ 317.6) .
- If the university chooses voluntary improvements instead of full retrofit, § 317.11 allows voluntary lateral‑system modifications only under § 319.12; because the building is state‑owned, the design documents must include the explicit disclaimer language in § 319.12.1.1 indicating the CEBC seismic requirements were not checked to full Section 317–322 standards .
Outcome: The owner cannot defer retrofit indefinitely — they must either retrofit now with the work or get the building official to accept a concrete plan (per § 317.6) or follow the voluntary modification procedures of § 319.12 with the required documentation if the project truly qualifies as voluntary .
Related provisions
- § 317.2 — Scope: evaluation and when only § 317.11 applies (exception language)
- § 317.3 — Applicability triggers (cost thresholds, percent changes, damage thresholds such as the 10 percent values used in applicability)
- § 317.5 — Minimum seismic performance levels (performance levels and hazard levels used to judge compliance)
- § 321.1 — Method B evaluation/peer review acceptance when used to demonstrate adequacy (relevant to deciding whether retrofit is required)
- § 322 — Project peer review requirements where seismic isolation or passive energy systems are used (referenced by the retrofit provisions)
Code references
Grounded in the retrieved California Existing Building Code — click a citation to read the verbatim passage:
CEBC § 319.1 High relevance — show source text
Buildings complying with the requirements of the exception in Section 319.1 are deemed to meet the seismic performance requirements of this section._
4. State-owned and state-leased essential services buildings are subject to the regulatory authority of DSA-SS per Section 1.9.2.1.|317.6 Retrofit required. Where the evaluation indicates the building does not meet the required performance objectives of this section, the owner shall take appropriate steps to ensure that the building’s structural system is retrofitted in accordance with the provisions of Section 317. Appropriate steps are either: 1) undertake the seismic retrofit as part of the additions, alterations and/or repairs of the structure; or 2) provide a plan, acceptable to the building official, to complete the seismic retrofit in a timely manner. The relocation or moving of an existing building is considered to be an alteration requiring filing of the plans and specifications approved by the building official.
317.7 The additions, alteration or repair to any existing building are permitted to be prepared in accordance with the structural and nonstructural requirements for a new building as given in the California Building Code, applied to the entire building.
317.8 The requirements of ASCE 41 Chapters 14 and 15 are to apply to the use of seismic isolation and passive energy systems, respectively, for the repair, voluntary lateral-force-resisting system modification or retrofit of an existing structure. When seismic isolation or passive energy dissipation is used, the project must have project peer review as prescribed in Section 322.
317.9 Any construction required by this chapter shall include structural observation by the registered design professional who is responsible for the structural design in accordance with Section 319.10.
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317.10 Where Method B of Section 321 is used or is required by Section 319.7, the proposed method of building evaluation and design procedures must be accepted by the building official prior to the commencement of the work.
317.11 Voluntary lateral-force-resisting system modifications. Where the exception of Section 317.2 applies, modifications of existing structural components and additions of new structural components that are initiated for the purpose of improving the seismic performance of an existing structure and that are not required by other portions of this chapter are permitted under the requirements of Section 319.12.
SECTION 318 [BSC, DSA-SS & DSA-SS/CC]—DEFINITIONS
318.1 In addition to the definitions given in Section 202, for the purposes of Sections 317 through 323, certain terms are defined as follows:
[DSA-SS & DSA-SS/CC] For the purposes of Section 317 through 323, definitions of terms given in Section 4-207 or 4-314 of the California Administrative Code govern over those in Section 202.
ADDITION [BSC] means any work that increases the floor or roof area or the volume of enclosed space of an existing building, and is structurally attached to the existing building by connections that are required for transmitting vertical or horizontal loads between the addition and the existing structure.
CEBC § 2.3.2 High relevance — show source text
405 A .2.3.2 Extent of repair for compliant buildings. If the evaluation establishes that the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the damaged elements shall be permitted to be restored to their predamage condition.
405 A .2.3.3 Extent of repair for noncompliant buildings. If the evaluation does not establish that the lateral force-resisting system of the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the lateral forceresisting system, and its foundation, shall be retrofitted to comply with the provisions of this section. The wind loads for the repair and retrofit shall be those required by the building code in effect at the time of original construction, unless the damage was caused by wind, in which case the wind loads shall be in accordance with the California Building Code . The earthquake loads shall not be less than those required by the building code in effect at the time of original construction but not less than 75 percent of those prescribed in California Building Code Section 1613A. Alternatively, where the earthquake damage has not resulted in disproportionate earthquake damage or did not result in collapse, the retrofit shall be permitted to be performed in accordance with Section 304A.3.4.4 for SPC-2 buildings, Section 304A.3.4.5 for SPC-3, SPC-4D and SPC-4 buildings and Section 304A.3.4.6 for SPC-5 buildings. For SPC-5 buildings, the seismic hazard shall be permitted to be reduced to BSE-1E and BSE-2E. Use of Section 304A.3.4.5 to rehabilitate SPC-3, SPC-4D and SPC-4 buildings will result in re-classification of the building to SPC-4D. Noncompliant SPC-4 buildings may be rehabilitated to SPC-5 in accordance with Section 304A.3.4.6 using the reduced seismic hazard. New structural members and connections required by this rehabilitation design shall comply with the detailing provisions of this code for new buildings of similar structure, purpose and location.
405 A .2.4 Substantial structural damage to gravity load-carrying components. Gravity load-carrying components that have sustained substantial structural damage shall be retrofitted to comply with the applicable provisions for dead, live and snow loads in the California Building Code . Undamaged gravity load-carrying components, including undamaged foundation components, that receive dead, live or snow loads from retrofitted components shall also be retrofitted if required to comply with these design loads. New structural members and connections required by this rehabilitation design shall comply with the detailing provi- sions of this code for new buildings of similar structure, purpose and location.
405 A .2.4.1 Lateral force-resisting elements. Regardless of the level of damage to vertical elements of the lateral force-resisting system, if substantial structural damage to gravity load-carrying components was caused primarily by wind or seismic effects, then the building shall be evaluated in accordance with Section 405 A .2.3.1 and, if noncompliant, retrofitted in accordance with Section 405 A .2.3.3.
Exceptions:
CEBC § 1.9.2.1. High relevance — show source text
State-owned and state-leased essential services buildings are subject to the regulatory authority of DSA-SS per Section 1.9.2.1._|1. ASCE 41 provides acceptance criteria (e.g., m-factor, rotation) for Immediate Occupancy (S1), Life Safety (S3) and Collapse Prevention (S5), and specifies in Table 2-1 the method
to interpolate values for S-2 and S-4. When evaluating for the Hazards Reduced Nonstructural Performance Level, the requirements need not be greater than what would be
required by ASCE 7 nonstructural provisions for new construction.
2. Buildings evaluated and retrofitted to meet the structural and nonstructural requirements for a new building as given in the California Building Code as adopted by DSA or BSC, as
applicable, are deemed to meet the seismic performance requirements of this section.
3. Buildings complying with the requirements of the exception in Section 319.1 are deemed to meet the seismic performance requirements of this section.
4. State-owned and state-leased essential services buildings are subject to the regulatory authority of DSA-SS per Section 1.9.2.1.|1. ASCE 41 provides acceptance criteria (e.g., m-factor, rotation) for Immediate Occupancy (S1), Life Safety (S3) and Collapse Prevention (S5), and specifies in Table 2-1 the method
to interpolate values for S-2 and S-4. When evaluating for the Hazards Reduced Nonstructural Performance Level, the requirements need not be greater than what would be
required by ASCE 7 nonstructural provisions for new construction.
2. Buildings evaluated and retrofitted to meet the structural and nonstructural requirements for a new building as given in the California Building Code as adopted by DSA or BSC, as
applicable, are deemed to meet the seismic performance requirements of this section.
3. Buildings complying with the requirements of the exception in Section 319.1 are deemed to meet the seismic performance requirements of this section.
4. State-owned and state-leased essential services buildings are subject to the regulatory authority of DSA-SS per Section 1.9.2.1.|317.6 Retrofit required. Where the evaluation indicates the building does not meet the required performance objectives of this section, the owner shall take appropriate steps to ensure that the building’s structural system is retrofitted in accordance with the provisions of Section 317. Appropriate steps are either: 1) undertake the seismic retrofit as part of the additions, alterations and/or repairs of the structure; or 2) provide a plan, acceptable to the building official, to complete the seismic retrofit in a timely manner. The relocation or moving of an existing building is considered to be an alteration requiring filing of the plans and specifications approved by the building official.
317.7 The additions, alteration or repair to any existing building are permitted to be prepared in accordance with the structural and nonstructural requirements for a new building as given in the California Building Code, applied to the entire building.
317.8 The requirements of ASCE 41 Chapters 14 and 15 are to apply to the use of seismic isolation and passive energy systems, respectively, for the repair, voluntary lateral-force-resisting system modification or retrofit of an existing structure. When seismic isolation or passive energy dissipation is used, the project must have project peer review as prescribed in Section 322.
CEBC § 405.2.3.1 High relevance — show source text
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REPAIRS
- One- and two-family dwellings need not be evaluated or retrofitted for load combinations that include earthquake effects.
[BS] 405.2.3.1 Evaluation. The building shall be evaluated by a registered design professional, and the evaluation findings shall be submitted to the code official. The evaluation shall establish whether the lateral force-resisting system of the damaged building, including its foundation, if repaired to its predamage state, would comply with the provisions of the California Build- ing Code for load combinations that include wind effects, and with Section 304.3.2 of this code.
[BS] 405.2.3.2 Extent of repair for compliant buildings. If the evaluation establishes that the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the damaged elements shall be permitted to be restored to their predamage condition.
[BS] 405.2.3.3 Extent of repair for noncompliant buildings. If the evaluation does not establish that the lateral force-resisting system of the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the lateral forceresisting system, and its foundation, shall be retrofitted to comply with the provisions of this section. The wind loads for the repair and retrofit shall be those required by the building code in effect at the time of original construction, unless the damage was caused by wind, in which case the wind loads shall be in accordance with the California Building Code . The seismic retrofit shall comply with Section 304.3.2 of this code, but the earthquake loads shall not be less than those required by the building code in effect at the time of original construction.
[BS] 405.2.4 Substantial structural damage to gravity load-carrying components. Gravity load-carrying components that have sustained substantial structural damage shall be retrofitted to comply with the applicable provisions for dead, live and snow loads in the California Building Code . Undamaged gravity load-carrying components, including undamaged foundation components, that receive dead, live or snow loads from retrofitted components shall also be retrofitted if required to comply with these design loads.
[BS] 405.2.4.1 Lateral force-resisting elements. Regardless of the level of damage to vertical elements of the lateral forceresisting system, if substantial structural damage to gravity load-carrying components was caused primarily by wind or seismic effects, then the building shall be evaluated in accordance with Section 405.2.3.1 and, if noncompliant, retrofitted in accordance with Section 405.2.3.3.
Exceptions:
- Buildings assigned to Seismic Design Category A, B or C whose substantial structural damage was not caused by earthquake need not be evaluated or retrofitted for load combinations that include earthquake effects.
- One- and two-family dwellings need not be evaluated or retrofitted for load combinations that include earthquake effects.
[BS] 405.2.5 Substantial structural damage to snow load-carrying components. Where substantial structural damage to any snow load-carrying components is caused by or related to snow load effects, any components required to carry snow loads on roof framing of similar construction shall be repaired, replaced or retrofitted to satisfy the requirements of Section 1608 of the California Building Code .
CEBC § 25.4 Medium relevance — show source text
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.
For Condition 1, both the lower stud and the upper stud shall be retrofitted using the methods of Section C104.2. For Condition 2, the retrofit stud shall be connected to the lower studs using the methods of Section C104.2 and be continuous from the bottom horizontal brace to the top horizontal brace. Connection is not required between the retrofit stud and the upper stud. In both conditions the bottom chord of the piggyback truss section shall be fastened to each retrofit stud using a connector with minimum axial capacity of 175 pounds (778 N).
[BS] C104.3 Retrofit studs. Retrofit studs shall be installed in accordance with Section C104.3.1 using one of the five methods of Section C104.3.2, C104.3.3, C104.3.4, C104.3.5 or C104.3.6. Figure C104.3 shows these methods of installation. For the Retrofit Configuration obtained from Table C104.2, the size of retrofit studs shall be as indicated in Table C104.4.1 or Table C104.4.2. Retrofit studs shall extend from the top of the lower horizontal brace to the bottom of the upper horizontal brace except that a maximum gap of [1] / 8 inch (3.2 mm) is permitted at the bottom and [1] / 2 inch (12.7 mm) at the top. 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.
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CEBC § 317.2 Medium relevance — show source text
317.2 Scope. All alterations, structurally connected additions and/or repairs to existing structures or portions thereof shall, at a minimum, be designed and constructed to resist the effects of seismic ground motions as provided in this section. The structural system shall be evaluated by a registered design professional and, if not meeting or exceeding the minimum seismic design performance requirements of this section, shall be retrofitted in compliance with these requirements.
Exception: Those structures for which Section 317.3 determines that assessment is not required, or for which Section 317.4 determines that retrofit is not needed, then only the requirements of Section 317.11 apply.
317.3 Applicability.
317.3.1 Existing state-owned buildings. [BSC, DSA-SS] For existing state-owned structures including all buildings owned by the University of California and the California State University, the requirements of Section 317 apply whenever the structure is to be retrofitted, repaired or modified and any of the following apply: 1. Total construction cost, not including cost of furnishings, fixtures and equipment, or normal maintenance, for the building exceeds 25 percent of the construction cost for the replacement of the existing building. The changes are cumulative for past modifications to the building that occurred after adoption of the 1995 California Building Code and did not require seismic retrofit.
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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.
CEBC § 1.9.2.1 Medium relevance — show source text
SECTION 323 [DSA-SS, DSA-SS/CC]—ADDITIONAL REQUIREMENTS FOR PUBLIC SCHOOLS AND COMMUNITY COLLEGES
The requirements of Section 323 apply only to public schools under the jurisdiction of the Division of the State Architect-Structural Safety (DSA-SS, refer to Section 1.9.2.1) and community colleges under the jurisdiction of the Division of the State Architect—Structural Safety/Community Colleges (DSA-SS/CC, refer to Section 1.9.2.2).
323.1 Evaluation and design criteria report. During the schematic phase of the project, the owner or the registered design professional in charge of the design shall prepare and sign an Evaluation and Design Criteria Report in accordance with Sections 4-306 and 4-307(a) of the California Administrative Code. The report shall be submitted to the DSA for review and approval prior to proceeding with design development of the rehabilitation.
The Evaluation and Design Criteria Report shall: 1. Identify the building(s) structural and nonstructural systems, potential deficiencies in the elements or systems and the proposed method for retrofit.
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2. Identify geological and site-related hazards. 3. Propose the methodology for evaluation and retrofit design. 4. Propose the complete program for data collection (Section 319.2). 5. Include existing or “as-built” building plans, reports and associated documents of the existing construction.
323.2 Rehabilitation involving only portions of structures. Where only a portion(s) of a structure is to be rehabilitated, the public school or community college portion of the structure shall: 1. Be seismically separated from the unrehabilitated portion in accordance with Chapter 16 of the California Building Code, or the entire structure shall be rehabilitated in accordance with this section. For structures in which the unrehabilitated portion is above or below the school or community college portion, the entire structure shall be rehabilitated in accordance with this division.
2. Be retrofitted as necessary to protect the occupants from falling hazards of the unrehabilitated portion of the building, and; 3. Be retrofitted as necessary to protect required exitways being blocked by collapse or falling hazards of the unrehabilitated portion.
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CALIFORNIA EXISTING BUILDING CODE – MATRIX ADOPTION TABLE
CHAPTER 3A – PROVISIONS FOR ALL COMPLIANCE METHODS [OSHPD1]
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
CEBC § 405.2.1 Medium relevance — show source text
[BS] 405.2.1 Repairs for less than substantial structural damage. Unless otherwise required by this section, for damage less than substantial structural damage, the damaged elements shall be permitted to be restored to their predamage condition.
[BS] 405.2.1.1 Snow damage. Structural components whose damage was caused by or related to snow load effects shall be repaired, replaced or altered to satisfy the requirements of Section 1608 of the California Building Code .
[BS] 405.2.2 Disproportionate earthquake damage. A building assigned to Seismic Design Category D, E or F that has sustained disproportionate earthquake damage shall be subject to the requirements for buildings with substantial structural damage to vertical elements of the lateral force-resisting system.
[BS] 405.2.3 Substantial structural damage to vertical elements of the lateral force-resisting system. A building that has sustained substantial structural damage to the vertical elements of its lateral force-resisting system shall be evaluated in accordance with Section 405.2.3.1, and either repaired in accordance with Section 405.2.3.2 or repaired and retrofitted in accordance with Section 405.2.3.3, depending on the results of the evaluation.
Exceptions:
- Buildings assigned to Seismic Design Category A, B or C whose substantial structural damage was not caused by earthquake need not be evaluated or retrofitted for load combinations that include earthquake effects.
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REPAIRS
- One- and two-family dwellings need not be evaluated or retrofitted for load combinations that include earthquake effects.
[BS] 405.2.3.1 Evaluation. The building shall be evaluated by a registered design professional, and the evaluation findings shall be submitted to the code official. The evaluation shall establish whether the lateral force-resisting system of the damaged building, including its foundation, if repaired to its predamage state, would comply with the provisions of the California Build- ing Code for load combinations that include wind effects, and with Section 304.3.2 of this code.
[BS] 405.2.3.2 Extent of repair for compliant buildings. If the evaluation establishes that the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the damaged elements shall be permitted to be restored to their predamage condition.
[BS] 405.2.3.3 Extent of repair for noncompliant buildings. If the evaluation does not establish that the lateral force-resisting system of the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the lateral forceresisting system, and its foundation, shall be retrofitted to comply with the provisions of this section. The wind loads for the repair and retrofit shall be those required by the building code in effect at the time of original construction, unless the damage was caused by wind, in which case the wind loads shall be in accordance with the California Building Code . The seismic retrofit shall comply with Section 304.3.2 of this code, but the earthquake loads shall not be less than those required by the building code in effect at the time of original construction.
CEBC § 405.2.4 Medium relevance — show source text
[BS] 405.2.4 Substantial structural damage to gravity load-carrying components. Gravity load-carrying components that have sustained substantial structural damage shall be retrofitted to comply with the applicable provisions for dead, live and snow loads in the California Building Code . Undamaged gravity load-carrying components, including undamaged foundation components, that receive dead, live or snow loads from retrofitted components shall also be retrofitted if required to comply with these design loads.
[BS] 405.2.4.1 Lateral force-resisting elements. Regardless of the level of damage to vertical elements of the lateral forceresisting system, if substantial structural damage to gravity load-carrying components was caused primarily by wind or seismic effects, then the building shall be evaluated in accordance with Section 405.2.3.1 and, if noncompliant, retrofitted in accordance with Section 405.2.3.3.
Exceptions:
- Buildings assigned to Seismic Design Category A, B or C whose substantial structural damage was not caused by earthquake need not be evaluated or retrofitted for load combinations that include earthquake effects.
- One- and two-family dwellings need not be evaluated or retrofitted for load combinations that include earthquake effects.
[BS] 405.2.5 Substantial structural damage to snow load-carrying components. Where substantial structural damage to any snow load-carrying components is caused by or related to snow load effects, any components required to carry snow loads on roof framing of similar construction shall be repaired, replaced or retrofitted to satisfy the requirements of Section 1608 of the California Building Code .
[BS] 405.2.6 Flood hazard areas. In flood hazard areas, buildings that have sustained substantial damage shall be brought into compliance with Section 1612 of the California Building Code or Section R306 of the California Residential Code, as applicable.
SECTION 406—ELECTRICAL
[OSHPD 1R, 2, 4 & 5] Not adopted by OSHPD. Existing electrical wiring and equipment undergoing repair shall be in accordance with Title 24 Part 3 California Electrical Code (CEC).
406.1 General. Repairs to existing electrical wiring and equipment shall be in accordance with the California Electrical Code.
406.1.1 Reconditioned electrical equipment. Reconditioned electrical equipment shall comply with the California Electrical Code . Electrical equipment prohibited from being reconditioned by the applicable sections of the California Electrical Code shall not be reconditioned unless permitted by NFPA 99.
406.1.2 Health care facilities. Portions of electrical systems being repaired in Group I-2, ambulatory care facilities and outpatient clinics shall comply with NFPA 99 requirements for repairs.
SECTION 407—MECHANICAL
407.1 General. Existing mechanical systems undergoing repair shall not make the building less complying than it was before the damaged occurred. [HCD 1, HCD 2 & BSC] Existing mechanical systems undergoing repair shall comply with the California Mechanical Code.
SECTION 408—PLUMBING
408.1 Materials. Plumbing materials and supplies shall not be used for repairs that are prohibited in the California Plumbing Code .
CEBC § 12.3 Medium relevance — show source text
APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS
For structures assigned to Seismic Design Category C or D, values of R, Ω 0 and C d shall be permitted to be based on the seismic force-resisting system being used to achieve the required strengthening, provided that when the strengthening is complete, the strengthened structure will not have an extreme weak story irregularity defined as Type 5b in ASCE 7, Table 12.3-2.
For structures assigned to Seismic Design Category E, values of R, Ω 0 and C d shall be permitted to be based on the seismic force-resisting system being used to achieve the required strengthening, provided that when the strengthening is complete, the strengthened structure will not have an extreme soft story, a weak story, or an extreme weak story irregularity defined, respectively, as Types 1b, 5a and 5b in ASCE 7, Table 12.3-2.
For retrofit systems involving different seismic force-resisting systems in the same direction within the same story, resisting elements are permitted to be designed using the least value of R for the different structural systems found in each independent line of resistance if all of the following conditions are met: 4.1. The building is assigned to Risk Category I or II. 4.2. The building height is no more than four stories above grade plane. 4.3. The seismic force-resisting systems of the retrofitted building comprise only wood structural panel shear walls, steel moment-resisting frames, steel cantilever columns and steel-braced frames. Values for C and Ω 0 shall be consistent with the R value used.
With reference to ASCE 7, Table 12.2-1, ordinary, intermediate and special steel systems, and all light-frame systems shall be permitted without limitation where those systems are used only for retrofit to comply with the requirements of this chapter.
[BS] A403.3.1 Expected story strength. Despite any other requirement of Section A403.3 or A403.4, the total expected strength of retrofit elements added to any story need not exceed 1.7 times the expected strength of the story immediately above in a twostory building, or 1.3 times the expected strength of the story immediately above in a three-story or taller building, as long as the retrofit elements are located symmetrically about the center of mass of the story above, or so as to minimize torsion in the retrofitted story. Calculation of expected story strength and identification of irregularities in Section A403.3 shall be based on the expected strength of all wall lines, even if sheathed with nonconforming materials. The strength of a wall line above the retrofitted story shall be permitted to be reduced to account for inadequate load path or overturning resistance.
[BS] A403.3.2 Seismicity parameters, site class and geologic hazards. For any site designated as Site Class E, the value of F shall be taken as 1.2. Site-specific procedures are not required for compliance with this chapter. Mitigation of existing geologic site hazards such as liquefiable soil, fault rupture or landslide is not required for compliance with this chapter.
CEBC § 12.2 Medium relevance — show source text
Values for C and Ω 0 shall be consistent with the R value used.
- With reference to ASCE 7, Table 12.2-1, ordinary, intermediate and special steel systems, and all light-frame systems shall be permitted without limitation where those systems are used only for retrofit to comply with the requirements of this chapter.
[BS] A403.3.1 Expected story strength. Despite any other requirement of Section A403.3 or A403.4, the total expected strength of retrofit elements added to any story need not exceed 1.7 times the expected strength of the story immediately above in a twostory building, or 1.3 times the expected strength of the story immediately above in a three-story or taller building, as long as the retrofit elements are located symmetrically about the center of mass of the story above, or so as to minimize torsion in the retrofitted story. Calculation of expected story strength and identification of irregularities in Section A403.3 shall be based on the expected strength of all wall lines, even if sheathed with nonconforming materials. The strength of a wall line above the retrofitted story shall be permitted to be reduced to account for inadequate load path or overturning resistance.
[BS] A403.3.2 Seismicity parameters, site class and geologic hazards. For any site designated as Site Class E, the value of F shall be taken as 1.2. Site-specific procedures are not required for compliance with this chapter. Mitigation of existing geologic site hazards such as liquefiable soil, fault rupture or landslide is not required for compliance with this chapter.
[BS] A403.4 Story drift limitations. The calculated story drift for each retrofitted story shall not exceed the allowable deformation compatible with all vertical load-resisting elements and 0.025 times the story height. The calculated story drift shall not be reduced by the effects of horizontal diaphragm stiffness but shall be increased where these effects produce rotation. Drift calculations shall be in accordance with the building code.
[BS] A403.4.1 Pole structures. The effects of rotation and soil stiffness shall be included in the calculated story drift where lateral loads are resisted by vertical elements whose required depth of embedment is determined by pole formulas. The coefficient of subgrade reaction used in deflection calculations shall be based on a geotechnical investigation conducted in accordance with the building code.
[BS] A403.5 Deformation compatibility and P Δ effects. The requirements of the building code shall apply, except as modified herein. Structural framing elements and their connections not required by design to be part of the lateral force-resisting system shall be designed and detailed to be adequate to maintain support of expected gravity loads when subjected to the expected deformations caused by seismic forces. Increased demand caused by P Δ effects and story sidesway stability shall be considered in retrofit stories that rely on the strength and stiffness of cantilever columns for lateral resistance.
[BS] A403.6 Ties and continuity. All parts of the structure included in the scope of Section A403.2 shall be interconnected as required by the building code.
[BS] A403.7 Collector elements. Collector elements shall be provided to transfer the seismic forces between the elements within the scope of Section A403.2.
CEBC § 317.1.2.1 Medium relevance — show source text
The provisions of Section 317 through 323 also establish minimum standards for earthquake evaluation and design for rehabilitation of existing public buildings currently under the jurisdiction of DSA-SS.
317.1.2.1 Reference to other chapters. For public schools, where reference within this chapter is made to sections in Chapters 16, 17, 18, 19, 21 or 22 of the California Building Code, the provisions in Chapters 16A, 17A, 18A, 19A, 21A and 22A of the California Building Code, respectively, shall apply instead.
317.1.3 Community college buildings. [DSA-SS/CC] The provisions of Sections 317 through 323 establish minimum standards for earthquake evaluation and design for the rehabilitation of existing buildings for use as community college buildings under the jurisdiction of the Division of the State Architect—Structural Safety/Community Colleges [DSA-SS/CC], refer to Section 1.9.2.2.
The provisions of Section 317 through 323 also establish minimum standards for earthquake evaluation and design for rehabilitation of existing community college buildings currently under the jurisdiction of DSA-SS/CC.
317.1.3.1 Reference to other chapters. For community colleges, where reference within this chapter is made to sections in Chapters 17 or 18 of the California Building Code, the provisions in Chapters 17A and 18A of the California Building Code, respectively, shall apply instead.
317.2 Scope. All alterations, structurally connected additions and/or repairs to existing structures or portions thereof shall, at a minimum, be designed and constructed to resist the effects of seismic ground motions as provided in this section. The structural system shall be evaluated by a registered design professional and, if not meeting or exceeding the minimum seismic design performance requirements of this section, shall be retrofitted in compliance with these requirements.
Exception: Those structures for which Section 317.3 determines that assessment is not required, or for which Section 317.4 determines that retrofit is not needed, then only the requirements of Section 317.11 apply.
317.3 Applicability.
317.3.1 Existing state-owned buildings. [BSC, DSA-SS] For existing state-owned structures including all buildings owned by the University of California and the California State University, the requirements of Section 317 apply whenever the structure is to be retrofitted, repaired or modified and any of the following apply: 1. Total construction cost, not including cost of furnishings, fixtures and equipment, or normal maintenance, for the building exceeds 25 percent of the construction cost for the replacement of the existing building. The changes are cumulative for past modifications to the building that occurred after adoption of the 1995 California Building Code and did not require seismic retrofit.
3-16 2025 CALIFORNIA EXISTING BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
PROVISIONS FOR ALL COMPLIANCE METHODS
Frequently asked questions
Can I delay a retrofit by promising to do it “later” without filing any plan?
No. If an evaluation shows noncompliance, § 317.6 requires either doing the retrofit with the current work or submitting a retrofit plan that the building official accepts; an unfiled, unspecified promise is not sufficient .
What counts as a “voluntary” modification that escapes full retrofit rules?
A voluntary modification is one initiated solely to improve seismic performance and not required by other portions of the chapter; such voluntary lateral‑system modifications are governed by § 317.11 and must follow § 319.12 procedures and documentation .
If I move a building off its foundation, do I need to retrofit?
Yes — relocation/moving is treated as an alteration, which triggers the same filing and retrofit responsibilities described in § 317.6 .
For state‑owned buildings, are there extra paperwork requirements for voluntary work?
Yes. When § 319.12 is used for state‑owned buildings, design documents must clearly state scope and include the phrase required by § 319.12.1.1 that the CEBC seismic requirements have not been fully checked and that a different performance standard is being used .
Who decides whether a retrofit plan is “timely” or “acceptable”?
The building official must accept the owner’s plan to complete the retrofit in a timely manner as described in § 317.6 — it is not an owner‑only decision .
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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