CHBC · California Historical Building Code

Can I change a historical building’s occupancy and what triggers CHBC requirements?

If you own a qualified historical building and apply for a permit to change its use, the CHBC lets you make that change so long as the building meets the CHBC rules for the new occupancy; the code explicitly says such a change does not automatically require compliance with regular new‑construction requirements, though CHBC life‑safety, accessibility and unsafe‑condition rules still apply (see **§ 8-302.2** and **§ 8-102.1.3**).

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

The California Historical Building Code allows a qualified historical building or property to change or return to a different use so long as the building conforms to the CHBC requirements for the new use; such a change is not required to meet regular new‑construction rules. See § 8-302.2 for the change‑of‑occupancy rule and § 8-102.1.3 directing change‑of‑use matters to Chapter 8‑3 of the CHBC.

If your building is a qualified historical building and you seek a permit to change its use, the CHBC lets you make that change provided the building meets the CHBC requirements for the new occupancy — it does not automatically force full new‑construction compliance. § 8-302.2

Requirements in detail

When the CHBC applies (the trigger)

  • The CHBC applies to a structure that is a qualified historical building or property and when a permit or approval is requested for work that affects its use or occupancy. See § 8-102.1 and § 8-301.2.
  • For a change of use or occupancy, the CHBC directs you to Chapter 8‑3 (Use and Occupancy); this is the procedural trigger for application of the CHBC rules on occupancy change. See § 8-102.1.3.

What “conforms to the CHBC requirements for the new use” means

  • The building must meet the CHBC provisions that apply to the new occupancy or character of use (for example, CHBC egress, fire‑safety and occupancy separation provisions), not the regular code’s new‑construction requirements. See § 8-302.2.
  • The CHBC contains specific related rules that may apply as part of conformity (examples: occupancy separations, maximum floor area, means of egress and accessibility alternatives). See § 8-302.3, § 8-302.4, § 8-503, and accessibility chapters.

Decision table — key dimensions to check

Decision question Relevant values / thresholds What to do Code Reference
Is the building a qualified historical building or property? Yes / No If Yes, CHBC may apply; if No, use regular code. § 8-101.1 / § 8-102.1
Is a permit or approval requested for the change? Permit requested = trigger Use CHBC classification procedures before permit issuance. § 8-301.2
Is the work a change of use or occupancy? Change of use / occupancy = Chapter 8‑3 applies Apply CHBC Chapter 8‑3 requirements; conformity required. § 8-102.1.3
Must the building meet regular new‑construction code? No (permitted exception) CHBC change does not mandate new‑construction conformance. § 8-302.2
Are there specific CHBC conditions that apply to the new use? Fire separations, sprinkler exceptions, floor area limits, egress Review CHBC sections (e.g., § 8-302.3, § 8-302.4, egress, accessibility). § 8-302.3, § 8-302.4, § 8-503

Administrative and policy notes

  • The enforcing agency must classify the qualified historical building according to its use prior to permit issuance. § 8-301.2 requires classification before permits.
  • The CHBC is intended to provide alternative solutions and allow reasonable equivalencies to the regular code when preserving historical character. See CHBC intent and purpose.

Exceptions & special cases

  • The CHBC explicitly states a change in occupancy shall not mandate conformance with new‑construction requirements of the regular code — i.e., you are not automatically required to rebuild to current new‑construction standards when changing occupancy under the CHBC. § 8-302.2
  • If the building is determined unsafe, the CHBC applies to the work necessary to correct the unsafe conditions and does not require bringing the entire building into regular‑code compliance; see § 8-102.1.5.
  • Accessibility and other mandated corrections: CHBC limits additional work to that required to complete the work undertaken, but notes certain accessibility obligations and distinct hazards may require specific action even under CHBC—see § 8-102.1.6. If strict compliance would destroy historic character, CHBC provides alternative provisions for access on an item‑by‑item basis (documentation required).
  • Specific CHBC provisions can ease or modify fire separations and area limits where, for example, an automatic sprinkler system is installed (see § 8-302.3 and the referenced Section 8-410.2). Review those sections when sprinklering is part of the upgrade.

Common mistakes

  • Mistaking CHBC allowance for a blanket exemption from safety upgrades. The CHBC relaxes new‑construction mandates but still requires conformity to CHBC requirements for the new use (§ 8-302.2).
  • Assuming no permit or classification is needed. The CHBC requires classification and application of CHBC provisions when a permit/approval is requested for a qualified historical building (§ 8-301.2, § 8-102.1).
  • Confusing “change of occupancy” under CHBC with detailed technical thresholds found in the regular Existing Building Code (CBC/CEBC). The CHBC directs you to its Chapter 8‑3 for occupancy matters; technical details not covered there may require coordination with the enforcing agency. § 8-102.1.3.

Worked example — concrete scenario with numbers

Scenario: You own a qualified historical one‑story former warehouse (historic use: Group S) of 12,000 sq ft you want to convert to a mixed use with a small museum and offices (new use: Group B/A mixed use). You will submit plans and a permit request.

Steps and how the CHBC applies:

  1. Confirm qualification and file for permit. CHBC applies because the building is a qualified historical building and you requested a permit — see § 8-102.1 and § 8-301.2.
  2. Because this is a change of use/occupancy, Chapter 8‑3 applies per § 8-102.1.3; the building must conform to CHBC requirements applicable to the new occupancy.
  3. You do NOT automatically have to rebuild to current new‑construction standards simply because of the change (CHBC exception in § 8-302.2). However, you must meet CHBC provisions that apply to the new use (for example, egress and life‑safety aspects). § 8-302.2.
  4. If you choose to add an automatic sprinkler system, you may be eligible for reduced occupancy separation requirements or unlimited floor area exceptions described in CHBC § 8-302.3 and § 8-302.4 (note: CHBC lists a 15,000 sq ft floor‑area threshold relevant to one‑story buildings). In this case, your 12,000 sq ft is below the 15,000 sq ft limit but reviewing § 8-302.4 is required if you later expand.
  5. The enforcing agency will review classification and approve the permit once the submitted work conforms to the CHBC solutions for the intended new occupancy (coordinate documentation, especially where CHBC allows alternatives to preserve historic features). See § 8-301.2 and the CHBC intent sections.

Related provisions (CHBC sections to review)

  • § 8-102.1 — Application (CHBC applicability and agency authority).
  • § 8-102.1.3 — Change of occupancy (points to Chapter 8‑3).
  • § 8-301.2 — Classification required prior to permit issuance.
  • § 8-302.1 — Continued existing use allowed (where appropriate).
  • § 8-302.2 — Change in occupancy rule (controlling provision).
  • § 8-302.3 — Occupancy separations and sprinkler interactions.
  • § 8-302.4 — Maximum floor area (15,000 sq ft threshold for one‑story).
  • § 8-503 — Escape or rescue windows and related egress provisions.
  • § 8-601 et seq. — Accessibility: scope and alternatives for historic buildings.
  • § 8-102.1.5 & § 8-102.1.6 — Unsafe buildings and limits on additional work required by regular code.

If you need, I can:

  • Map the specific CHBC chapters and sections that will apply to your exact proposed occupancy (given building type, area and scope of work), or
  • Draft a short checklist you can bring to the enforcing agency to speed up the permit review.

Code references

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

  • CHBC § 8-3 High relevance — show source text

    TREATMENT. An act of work to carry out preservation, restoration, stabilization, rehabilitation or reconstruction.

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    8-3 USE AND OCCUPANCY

    SECTION 8-301 — PURPOSE AND SCOPE

    8-301.1 Purpose. The purpose of the CHBC is to provide regulations for the determination of occupancy classifications and conditions of use for qualified historical buildings or properties.

    8-301.2 Scope. Every qualified historical building or property for which a permit or approval has been requested shall be classified prior to permit issuance according to its use or the character of its occupancy in accordance with the regular code and applicable provisions of this chapter.

    SECTION 8-302 — GENERAL

    8-302.1 Existing use. The use or character of occupancy of a qualified historical building or property, or portion thereof, shall be permitted to continue in use regardless of any period of time in which it may have remained unoccupied or in other uses, provided such building or property otherwise conforms to all applicable requirements of the CHBC.

    8-302.2 Change in occupancy. The use or character of the occupancy of a qualified historical building or property may be changed from or returned to its historical use or character, provided the qualified historical building or property conforms to the requirements applicable to the new use or character of occupancy as set forth in the CHBC. Such change in occupancy shall not mandate conformance with new construction requirements as set forth in regular code.

    8-302.3 Occupancy separations. Required occupancy separations of more than one hour may be reduced to one-hour fire-resistive construction with all openings protected by not less than three-fourths-hour fire-resistive assemblies of the self-closing or automatic-closing type when the building is provided with an automatic sprinkler system throughout the entire building in accordance with Section 8-410.2. Doors equipped with automatic-closing devices shall be of a type which will function upon activation of a device which responds to products of combustion other than heat.

    Required occupancy separations of one hour may be omitted when the building is provided with an automatic sprinkler system throughout.

    8-302.4 Maximum floor area. Regardless of the use or character of occupancy, the area of a one-story qualified historical building or property may have, but shall not exceed, a floor area of 15,000 square feet (1393.5 m [2] ) unless such an increase is otherwise permitted in regular code. Multistory qualified historical buildings (including basements and cellars) shall be in accordance with regular code requirements.

    Exception: Historical buildings may be unlimited in floor area without fire-resistive area separation walls:

    1. When provided with an automatic sprinkler, or
    2. Residential occupancies of two stories or less when provided with a complete fire alarm and annunciation system and where the exiting system conforms to regular code.

    8-302.5 Maximum height. The maximum height and number of stories of a qualified historical building or property shall not be limited because of construction type, provided such height or number of stories does not exceed that of its historical design.

  • CHBC § 8-3 High relevance — show source text

    This shall include historical buildings or properties on, or determined eligible for, national, state or local historical registers or inventories, such as the National Register of Historic Places, California Register of Historical Resources, State Historical Landmarks, State Points of Historical Interest, and city or county registers, inventories or surveys of historical or architecturally significant sites, places or landmarks.

    RECONSTRUCTION. The act or process of depicting, by means of new construction, the form, features and detailing of a nonsurviving site, landscape, building, property or object for the purpose of replicating its appearance at a specific period of time.

    REGULAR CODE. The adopted regulations that govern the design and construction or alteration of nonhistorical buildings and properties within the jurisdiction of the enforcing agency.

    REHABILITATION. The act or process of making possible a compatible use for qualified historical building or property through repair, alterations and additions while preserving those portions or features which convey its qualified historical, cultural or architectural values.

    RELOCATION. The act or process of moving any qualified historical building or property or a portion of a qualified historical building or property to a new site, or a different location on the same site.

    REPAIR. Renewal, reconstruction or renovation of any portion of an existing property, site or building for the purpose of its continued use.

    RESTORATION. The act or process of accurately depicting the form, features and character of a qualified building or property as it appeared at a particular period of time by the means of the removal of features from other periods in its history and reconstruction of missing features from the restoration period. The limited and sensitive upgrading of mechanical, electrical and plumbing systems and other code-required work to make properties functional is appropriate within a restoration project.

    STRUCTURE. That which is built or constructed, an edifice or a building of any kind, or any piece of work artificially built up or composed of parts joined together in some definite manner.

    TREATMENT. An act of work to carry out preservation, restoration, stabilization, rehabilitation or reconstruction.

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    8-3 USE AND OCCUPANCY

    SECTION 8-301 — PURPOSE AND SCOPE

    8-301.1 Purpose. The purpose of the CHBC is to provide regulations for the determination of occupancy classifications and conditions of use for qualified historical buildings or properties.

    8-301.2 Scope. Every qualified historical building or property for which a permit or approval has been requested shall be classified prior to permit issuance according to its use or the character of its occupancy in accordance with the regular code and applicable provisions of this chapter.

    SECTION 8-302 — GENERAL

    8-302.1 Existing use. The use or character of occupancy of a qualified historical building or property, or portion thereof, shall be permitted to continue in use regardless of any period of time in which it may have remained unoccupied or in other uses, provided such building or property otherwise conforms to all applicable requirements of the CHBC.

    8-302.2 Change in occupancy. The use or character of the occupancy of a qualified historical building or property may be changed from or returned to its historical use or character, provided the qualified historical building or property conforms to the requirements applicable to the new use or character of occupancy as set forth in the CHBC. Such change in occupancy shall not mandate conformance with new construction requirements as set forth in regular code.

  • CHBC § 8-102.1.1 High relevance — show source text
    1. State agencies. All state agencies shall apply the provisions of the CHBC in permitting repairs, alterations and additions necessary for the preservation, restoration, rehabilitation, safety, relocation, reconstruction or continued use of qualified historical buildings or properties.

    8-102.1.1 Additions, alterations and repairs. It is the intent of the CHBC to allow nonhistorical expansion or addition to a qualified historical building or property, provided nonhistorical additions shall conform to the requirements of the regular code (as defined in Chapter 8-2).

    8-102.1.2 Relocation. Relocated qualified historical buildings or properties shall be sited to comply with the regular code or with the solutions listed in the CHBC. Nonhistorical new construction related to relocation shall comply with the regular code. Reconstruction and restoration related to relocation is permitted to comply with the provisions in the CHBC.

    8-102.1.3 Change of occupancy. For change of use or occupancy, see Chapter 8-3, Use and Occupancy.

    8-102.1.4 Continued use. Qualified historical buildings or properties may have their existing use or occupancy continued if such use or occupancy conformed to the code or to the standards of construction in effect at the time of construction, and such use or occupancy does not constitute a distinct hazard to life safety as defined in the CHBC.

    8-102.1.5 Unsafe buildings or properties. When a qualified historical building or property is determined to be unsafe as defined in the regular code, the requirements of the CHBC are applicable to the work necessary to correct the unsafe conditions. Work to remediate the buildings or properties need only address the correction of the unsafe conditions, and it shall not be required to bring the entire qualified historical building or property into compliance with regular code.

    8-102.1.6 Additional work. Qualified historical buildings or properties shall not be subject to additional work required by the regular code, regulation or ordinance beyond that required to complete the work undertaken. Certain exceptions for accessibility and for distinct hazards exist by mandate and may require specific action, within the parameters of the CHBC.

    SECTION 8-103 — ORGANIZATION AND ENFORCEMENT

    8-103.1 Authority. The state or local enforcing agency, pursuant to authority provided under Section 18954 of the Health and Safety Code, shall administer and enforce the provisions of the CHBC in permitting repairs, alterations and additions necessary for the preservation, restoration, reconstruction, rehabilitation, relocation or continued use of a qualified historical building or property.

    8-103.2 State enforcement. All state agencies pursuant to authority provided under Section 18954 and Section 18961 of the Health and Safety Code shall administer and enforce the CHBC with respect to qualified historical buildings or properties under their respective jurisdiction.

    8-103.3 Liability. Prevailing law regarding immunity of building officials is unaffected by the use and enforcement of the CHBC.

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    ADMINISTRATION

    SECTION 8-104 — REVIEW AND APPEALS

    8-104.1 State Historical Building Safety Board (SHBSB or Board). In order to provide for interpretation of the provisions of the CHBC and to hear appeals, the SHBSB shall act as an appeal and review body to state and local agencies or any affected party.

    **8-104.2 SHBSB review.

  • CHBC § 8-101.1 High relevance — show source text

    8-101.1 Title. These regulations shall be known as the California Historical Building Code and will be referred to herein as “the CHBC.”

    8-101.2 Purpose. The purpose of the CHBC is to provide regulations for the preservation, restoration, rehabilitation, relocation or reconstruction of buildings or properties designated as qualified historical buildings or properties (as defined in Chapter 8-2). The CHBC is intended to provide solutions for the preservation of qualified historical buildings or properties, to promote sustainability, to provide access for persons with disabilities, to provide a cost-effective approach to preservation, and to provide for the reasonable safety of the occupants or users. The CHBC requires enforcing agencies to accept solutions that are reasonably equivalent to the regular code (as defined in Chapter 8-2) when dealing with qualified historical buildings or properties.

    8-101.3 Intent. The intent of the CHBC is to facilitate the preservation and continuing use of qualified historical buildings or properties while providing reasonable safety for the building occupants and access for persons with disabilities.

    SECTION 8-102 — APPLICATION

    8-102.1 Application. The CHBC is applicable to all issues regarding code compliance for qualified historical buildings or properties. The CHBC may be used in conjunction with the regular code to provide solutions to facilitate the preservation of qualified historical buildings or properties. The CHBC shall be used by any agency with jurisdiction and whenever compliance with the code is required for qualified historical buildings or properties.

    1. State or local enforcing agency. The state or local enforcing agency shall apply the provisions of the CHBC in permitting repairs, alterations and additions necessary for the preservation, restoration, reconstruction, rehabilitation, relocation or continued use of a qualified historical building or property when so elected by the private property owner.
    2. State agencies. All state agencies shall apply the provisions of the CHBC in permitting repairs, alterations and additions necessary for the preservation, restoration, rehabilitation, safety, relocation, reconstruction or continued use of qualified historical buildings or properties.

    8-102.1.1 Additions, alterations and repairs. It is the intent of the CHBC to allow nonhistorical expansion or addition to a qualified historical building or property, provided nonhistorical additions shall conform to the requirements of the regular code (as defined in Chapter 8-2).

    8-102.1.2 Relocation. Relocated qualified historical buildings or properties shall be sited to comply with the regular code or with the solutions listed in the CHBC. Nonhistorical new construction related to relocation shall comply with the regular code. Reconstruction and restoration related to relocation is permitted to comply with the provisions in the CHBC.

    8-102.1.3 Change of occupancy. For change of use or occupancy, see Chapter 8-3, Use and Occupancy.

    8-102.1.4 Continued use. Qualified historical buildings or properties may have their existing use or occupancy continued if such use or occupancy conformed to the code or to the standards of construction in effect at the time of construction, and such use or occupancy does not constitute a distinct hazard to life safety as defined in the CHBC.

    8-102.1.5 Unsafe buildings or properties. When a qualified historical building or property is determined to be unsafe as defined in the regular code, the requirements of the CHBC are applicable to the work necessary to correct the unsafe conditions. Work to remediate the buildings or properties need only address the correction of the unsafe conditions, and it shall not be required to bring the entire qualified historical building or property into compliance with regular code.

  • CHBC § 1001.1 High relevance — show source text

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    10 CHANGE OF OCCUPANCY

    User notes:

    About this chapter : The purpose of this chapter is to provide regulations for the circumstances where an existing building is subject to a change of occupancy or a change of occupancy classification. A change of occupancy is not to be confused with a change of occupancy classification. The California Building Code defines different occupancy classifications in Chapter 3 and special occupancy requirements in Chapter 4. Within specific occupancy classifications there can be many different types of actual activities that can take place. For instance, a Group A-3 occupancy classification deals with a wide variation of different types of activities, including bowling alleys and courtrooms, indoor tennis courts and dance halls. When a facility changes use from, for example, a bowling alley to a dance hall, the occupancy classification remains A-3, but the different uses could lead to drastically different code requirements. Therefore, this chapter deals with the special circumstances that are associated with a change in the use of a building within the same occupancy classification as well as a change of occupancy classification.

    SECTION 1001—GENERAL

    1001.1 Scope. The provisions of this chapter shalle a change of occupancy occurs, as defined in Section 202.

    1001.2 Certificate of occupancy. A change of occupancy or a change of occupancy within a space where there is a different fire protection system threshold requirement in Chapter 9 of th apply where current California Building Code than exists in the current building or space shall not be made to any structure without the approval of the code official. A certificate of occupancy shall be issued where it has been determined that the requirements for the change of occupancy have been met.

    1001.2.1 Change of use. Any work undertaken in connection with a change in use shall conform to the applicable requirements for the work as classified in Chapter 6 and to the requirements of Sections 1002 through 1010.

    1001.2.2 Change of occupancy classification. Where a building undergoes a change of occupancy classification, the provisions of Sections 1002 through 1011 shall apply.

    1001.2.2.1 Partial change of occupancy. Where a portion of an existing building undergoes a change of occupancy classification, Section 1011 shall apply.

    1001.3 Certificate of occupancy required. A certificate of occupancy shall be issued where a change of occupancy occurs that results in a different occupancy classification as determined by the California Building Code .

    SECTION 1002—SPECIAL USE AND OCCUPANCY

    1002.1 Compliance with the building code. Where an existing building or part of an existing building undergoes a change of occupancy to one of the special use or occupancy categories as described in Chapter 4 in the California Building Code, the building shall comply with all of the requirements of Chapter 4 of the California Building Code applicable to the special use or occupancy.

    1002.2 Incidental uses. Where a portion of a building undergoes a change of occupancy to one of the incidental uses listed in Table 509.1 of the California Building Code, the incidental use shall comply with Section 509 of the California Building Code applicable to the incidental use.

    SECTION 1003—BUILDING ELEMENTS AND MATERIALS

    1003.1 General. Building elements and materials in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.

    SECTION 1004—FIRE PROTECTION

  • CHBC § 8-302.3 High relevance — show source text

    8-302.3 Occupancy separations. Required occupancy separations of more than one hour may be reduced to one-hour fire-resistive construction with all openings protected by not less than three-fourths-hour fire-resistive assemblies of the self-closing or automatic-closing type when the building is provided with an automatic sprinkler system throughout the entire building in accordance with Section 8-410.2. Doors equipped with automatic-closing devices shall be of a type which will function upon activation of a device which responds to products of combustion other than heat.

    Required occupancy separations of one hour may be omitted when the building is provided with an automatic sprinkler system throughout.

    8-302.4 Maximum floor area. Regardless of the use or character of occupancy, the area of a one-story qualified historical building or property may have, but shall not exceed, a floor area of 15,000 square feet (1393.5 m [2] ) unless such an increase is otherwise permitted in regular code. Multistory qualified historical buildings (including basements and cellars) shall be in accordance with regular code requirements.

    Exception: Historical buildings may be unlimited in floor area without fire-resistive area separation walls:

    1. When provided with an automatic sprinkler, or
    2. Residential occupancies of two stories or less when provided with a complete fire alarm and annunciation system and where the exiting system conforms to regular code.

    8-302.5 Maximum height. The maximum height and number of stories of a qualified historical building or property shall not be limited because of construction type, provided such height or number of stories does not exceed that of its historical design.

    8-302.5.1 High-rise buildings. Occupancies B, F-1, F-2 or S in high-rise buildings with floors located more than 75 feet above the lowest floor level having building access may be permitted with only the stories over 75 feet provided with an automatic fire sprinkler system if:

    1. The building construction type and the exits conform to regular code, and
    2. A complete building fire alarm and annunciation system is installed, and
    3. A fire barrier is provided between the sprinklered and nonsprinklered floors.

    8-302.6 Fire-resistive construction. See Chapter 8-4.

    8-302.7 Light and ventilation. Existing provisions for light and ventilation which do not, in the opinion of the enforcing agency, constitute a safety hazard may remain. See Section 8-303.6 for residential requirements. See Section 8-503 for Escape or Rescue Windows and Doors.

    SECTION 8-303 — RESIDENTIAL OCCUPANCIES

    8-303.1 Purpose. The purpose of this section is to provide regulations for those buildings designated as qualified historical buildings or properties and classified as residential occupancies. The CHBC requires enforcing agencies to accept any reasonably equivalent alternative to the regular code when dealing with qualified historical buildings and properties.

    8-303.2 Intent. The intent of the CHBC is to preserve the integrity of qualified historical buildings and properties while maintaining a reasonable degree of protection of life, health and safety for the occupants.

    8-303.3 Application and scope. The provisions of this section shall apply to all qualified historical buildings used for human habitation. Those dwelling units intended only for display, or public use with no residential use involved, need not comply with the requirements of this section.

    8-303.4 Fire escapes. See Chapter 8-5.

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  • CHBC § 323-9843 High relevance — show source text

    State Librarian [SL]

    library.ca.gov csllaw@library.ca.gov (916) 323-9843 Public Library Construction & Renovation

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    HOW TO DETERMINE WHERE CHANGES HAVE BEEN MADE

    Symbols in the margins indicate where changes have been made or language has been deleted.

    This symbol indicates that a change has been made.

    • This symbol indicates deletion of language.

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    PART 8 CONTAINS ALTERNATIVE REGULATIONS

    FOR QUALIFIED HISTORICAL BUILDINGS

    The California Historical Building Code (CHBC) is unique among state regulations. The authoring of the original CHBC required state agencies promulgating regulations for building construction to work in harmony with representatives of other design and construction disciplines. The result was a totally new approach to building codes for historical structures, which maintains currently acceptable life safety standards. These regulations are also unique in that they are performance oriented rather than prescriptive. The provisions of the CHBC are to be applied by the enforcing authority of every city, county, city and county, or state agency in permitting repairs, alterations and additions necessary for the preservation, rehabilitation, relocation, related construction, change of use or continued use of a qualified historical building. The authority for use of the CHBC is vested in Sections 18950 through 18961 of the Health and Safety Code. Section 18954 states, “The building department of every city or county or other local agency that has jurisdiction over the enforcement of code within its legal authority shall apply the alternative standards and regulations adopted pursuant to Section 18959.5 in permitting repairs, alterations, and additions necessary for the preservation, restoration, rehabilitation, safety, moving, or continued use of a qualified historical building or structure. A state agency shall apply the alternative regulations adopted pursuant to Section 18959.5 in permitting repairs, alterations, and additions necessary for the preservation, restoration, rehabilitation, safety, moving, or continued use of a qualified historical building or structure.” However, be aware that in order to use the CHBC, the structure under consideration must be qualified by being designated as an historical building or structure. Section 18955 states, “For the purposes of this part, a qualified historical building or structure is any structure or property, collection of structures, and their related sites deemed of importance to the history, architecture, or culture of an area by an appropriate local or state governmental jurisdiction. This shall include historical buildings or structures on existing or future national, state or local historical registers or official inventories, such as the National Register of Historic Places, State Historical Landmarks, State Points of Historical Interest, and city or county registers or inventories of historical or architecturally significant sites, places, historic districts, or landmarks. This shall also include places, locations, or sites identified on these historical registers or official inventories and deemed of importance to the history, architecture, or culture of an area by an appropriate local or state governmental jurisdiction.” The regulations of the CHBC have the same authority as state law and are to be considered as such. Liability is the same as for prevailing law. The intent of the CHBC is to save California’s architectural heritage by recognizing the unique construction problems inherent in historical buildings and by providing a code to deal with these problems.

  • CHBC § 1001.2.1 High relevance — show source text

    1001.2.1 Change of use. Any work undertaken in connection with a change in use shall conform to the applicable requirements for the work as classified in Chapter 6 and to the requirements of Sections 1002 through 1010.

    1001.2.2 Change of occupancy classification. Where a building undergoes a change of occupancy classification, the provisions of Sections 1002 through 1011 shall apply.

    1001.2.2.1 Partial change of occupancy. Where a portion of an existing building undergoes a change of occupancy classification, Section 1011 shall apply.

    1001.3 Certificate of occupancy required. A certificate of occupancy shall be issued where a change of occupancy occurs that results in a different occupancy classification as determined by the California Building Code .

    SECTION 1002—SPECIAL USE AND OCCUPANCY

    1002.1 Compliance with the building code. Where an existing building or part of an existing building undergoes a change of occupancy to one of the special use or occupancy categories as described in Chapter 4 in the California Building Code, the building shall comply with all of the requirements of Chapter 4 of the California Building Code applicable to the special use or occupancy.

    1002.2 Incidental uses. Where a portion of a building undergoes a change of occupancy to one of the incidental uses listed in Table 509.1 of the California Building Code, the incidental use shall comply with Section 509 of the California Building Code applicable to the incidental use.

    SECTION 1003—BUILDING ELEMENTS AND MATERIALS

    1003.1 General. Building elements and materials in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.

    SECTION 1004—FIRE PROTECTION

    1004.1 General. Fire protection requirements in Section 1011 shall apply where either of the following occur:

    1. A building or portion thereof undergoes a change of occupancy.
    2. A building or portion thereof undergoes a change of occupancy and there is a different fire protection system threshold requirement in Chapter 9 of the current California Building Code than exists in the current building or portion thereof.

    SECTION 1005—MEANS OF EGRESS

    1005.1 General. Means of egress in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.

    SECTION 1006—STRUCTURAL

    [BS] 1006.1 Live loads. Structural elements carrying tributary live loads from an area with a change of occupancy shall satisfy the requirements of Section 1607 of the California Building Code . Design live loads for areas of new occupancy shall be based on Section 1607 of the California Building Code . Design live loads for other areas shall be permitted to use previously approved design live loads.

    Exception: Structural elements whose demand-capacity ratio considering the change of occupancy is not more than 5 percent greater than the demand-capacity ratio based on previously approved live loads.

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    CHANGE OF OCCUPANCY

    [BS] 1006.2 Snow and wind loads. Where a change of occupancy results in a structure being assigned to a higher risk category, the structure shall satisfy the requirements of Sections 1608 and 1609 of the California Building Code for the new risk category.

  • CHBC § 1.10.1 High relevance — show source text

    Chapter 5A Prescriptive Compliance Method.

    Chapter 5A provides details for the prescriptive compliance method for alteration, addition and change of occupancy of existing build- ings and 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 6 Classification of Work.

    Chapter 6 provides an overview of the Work Area Method and defines the different classifications of work including alterations, change of occupancy, additions and historic buildings. Detailed requirements for all of these are given in subsequent Chapters 7 through 11.

    Chapter 7 Alterations—Level 1.

    Chapter 7 provides the technical requirements for those existing buildings that undergo Level 1 alterations as described in Section 602, which includes replacement or covering of existing materials, elements, equipment or fixtures using new materials for the same purpose. This chapter is distinguished from Chapters 8 and 9 by only involving replacement of building components with new components with no reconfiguration of space.

    Chapter 8 Alterations—Level 2.

    A Level 2 alteration is an alteration involving space reconfiguration that could be up to and including 50 percent of the area of the building or addition of a new building system. Level 2 alterations also include the extension or addition of any system or equipment. The purpose of Chapter 8 is to provide detailed requirements and provisions to identify the required improvements in the existing building elements, means of egress, fire protection, structural systems, energy efficiency, and other building systems include electrical, mechanical and plumbing when a building is being altered.

    Chapter 9 Alterations—Level 3.

    Chapter 9 provides the technical requirements for those existing buildings that undergo Level 3 alterations. Level 3 alterations are those involving alterations that cover 50 percent of the aggregate area of the building. Under certain situations, this chapter also intends to improve the safety of certain building features beyond the work area and in other parts of the building where no alteration work might be taking place.

    Chapter 10 Change of Occupancy.

    The purpose of Chapter 10 is to address existing buildings that are subject to a change of occupancy. This chapter is an assembly of requirements to upgrade safety without having to comply fully as a new building. A change of occupancy classification is considered a change of occupancy, however, it will involve a higher level of regulation since the use of the building has made a more significant change.

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    Chapter 11 Additions.

    Chapter 11 provides the requirements for additions, which are considered new construction. The requirements focus on safely integrating the addition with the existing building. This includes issues such as limiting the overall height and area of the building where the addition is not separated by a fire wall.

    Chapter 12 Historic Buildings —Reserved

    Chapter 12 is not adopted by the State of California. Historic buildings and structures shall comply with Part 8, Title 24, California Code of Regulations.

    Chapter 13 Performance Compliance Methods.

    Chapter 13 allows for existing buildings to be evaluated to show that alterations or a change of occupancy, while not meeting new construction requirements, will provide a level of safety to demonstrate compliance. Provisions are based on a numerical scoring system involving 21 safety parameters where, when evaluated, such buildings must meet a minimum overall safety score.

  • CHBC § 1011.6.2 High relevance — show source text

    1011.6.2 Height and area for change to an equal or lesser-hazard category. Where a change of occupancy classification is made to an equal or lesser-hazard category as shown in Table 1011.6, the height and area of the existing buildingshall be deemed acceptable.

    1011.6.3 Fire barriers. Where a change of occupancy classification is made to a higher-hazard category as shown in Table 1011.6, fire barriers in separated mixed use buildings shall comply with the fire-resistance requirements of the California Building Code .

    Exception: Where the fire barriers are required to have a 1-hour fire-resistance rating, existing wood lath and plaster in good condition or existing [1] / 2 -inch-thick (12.7 mm) gypsum wallboard shall be permitted.

    1011.7 Exterior wall fire-resistance ratings. Hazard categories in regard to fire-resistance ratings of exterior walls shall be in accordance with Table 1011.7.

    TABLE 1011.7—EXPOSURE OF EXTERIOR WALLS HAZARD CATEGORIES Col2
    RELATIVE HAZARD OCCUPANCY CLASSIFICATION
    1 (Highest Hazard) H
    2 F-1; M; S-1
    3 A; B; E; I; R
    4 (Lowest Hazard) F-2; S-2; U

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    CHANGE OF OCCUPANCY

    1011.7.1 Exterior wall rating for change of occupancy classification to a higher-hazard category. Where a change of occupancy classification is made to a higher hazard category as shown in Table 1011.7, exterior walls shall have fire-resistance, exterior opening areas and opening protectives as required by the California Building Code .

    Exception: A 2-hour fire-resistance rating shall be allowed where the building does not exceed three stories in height and is classified as one of the following groups: A-2 and A-3 with an occupant load of less than 300, B, F, M or S.

    1011.7.2 Exterior wall rating for change of occupancy classification to an equal or lesser-hazard category. Where a change of occupancy classification is made to an equal or lesser-hazard category as shown in Table 1011.7, existing exterior walls, including openings, shall be accepted.

    1011.7.3 Opening protectives. Openings in exterior walls shall be protected as required by the California Building Code . Where openings in the exterior walls are required to be protected because of their distance from the lot line, the sum of the area of such openings shall not exceed 50 percent of the total area of the wall in each story.

    Exceptions:

    1. Where the California Building Code permits openings in excess of 50 percent.

    2. Protected openings shall not be required in buildings of Group R occupancy that do not exceed three stories in height and that are located not less than 3 feet (914 mm) from the lot line.

    3. Exterior opening protectives are not required where an automatic sprinkler system has been installed throughout.

    4. Exterior opening protectives are not required where the change of occupancy group is to an equal or lower hazard classification in accordance with Table 1011.7.

  • CHBC § 0.33 Medium relevance — show source text

    Exceptions:

    1. Where the area of the new occupancy is less than 10 percent of the building area, the occupancy is not changing from a Group S or Group U occupancy, and the new occupancy is not assigned to Risk Category IV, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
    2. Where a change of use results in a building being reclassified from Risk Category I or II to Risk Category III and the seismic coefficient, S DS, is less than 0.33, compliance with this section is not required.
    3. Unreinforced masonry bearing wall buildings assigned to Risk Category III and to Seismic Design Category A or B, shall be permitted to use Appendix Chapter A1 of this code.
    4. Where the change is from a Group S or Group U occupancy and there is no change of risk category, compliance with Section 304.3.2 shall be permitted.

    [BS] 506.5.4 Access to Risk Category IV. Any structure that provides operational access to an adjacent structure assigned to Risk Category IV as the result of a change of occupancy shall itself comply with Sections 1608 and 1609 of the California Building Code and Section 304.3.1 of this code. Where operational access to the Risk Category IV structure is less than 10 feet (3048 mm) from either an interior lot line or from another structure, access protection from potential falling debris shall be provided.

    506.6 Enhanced classroom acoustics. In Group E occupancies, where the work area exceeds 50 percent of the building area, enhanced classroom acoustics shall be provided in all classrooms with a volume of 20,000 cubic feet (565 m [3] ) or less. Enhanced classroom acoustics shall comply with the reverberation time in Section 808 of ICC A117.1.

    SECTION 507—HISTORIC BUILDINGS

    507.1 Historic buildings. The provisions of the California Historical Building Code (Part 8, Title 24, C.C.R), shall apply to qualified historical buildings or properties.

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    CALIFORNIA EXISTING BUILDING CODE – MATRIX ADOPTION TABLE

    CHAPTER 5A – PRESCRIPTIVE COMPLIANCE METHOD [OSHPD 1]

    (Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

  • CHBC § 1009.3 Medium relevance — show source text

    1009.3 Interceptor required. If the new occupancy will produce grease or oil-laden wastes, interceptors shall be provided as required in the California Plumbing Code .

    1009.4 Chemical wastes. If the new occupancy will produce chemical wastes, the following shall apply:

    1. If the existing piping is not compatible with the chemical waste, the waste shall be neutralized prior to entering the drainage system or the piping shall be changed to a compatible material.
    2. Chemical waste shall not discharge to a public sewer system without the approval of the sewage authority.

    SECTION 1010—OTHER REQUIREMENTS

    1010.1 Light and ventilation. Light and ventilation shall comply with the requirements of the California Building Code for the new

    occupancy.

    SECTION 1011—CHANGE OF OCCUPANCY CLASSIFICATION

    1011.1 General. The provisions of this section shall apply to buildings or portions thereof undergoing a change of occupancy classification. This includes a change of occupancy classification within a group as well as a change of occupancy classification from one group to a different group. The provisions of this section shall also apply where there is a change of occupancy within a building or portion thereof and there is a different fire protection system threshold requirement in Chapter 9 of the current California Building Code than exists in the current building or space. Such buildings shall also comply with Sections 1002 through 1010 of this code.

    1011.2 Fire protection systems. Fire protection systems shall be provided in accordance with Sections 1011.2.1 and 1011.2.2.

    1011.2.1 Automatic sprinkler system. The installation of an automatic sprinkler system shall be required where there is a change of occupancy classification and Chapter 9 of the current California Building Code requires an automatic sprinkler system based on the new occupancy or where there is a change of occupancy within the space where there is a different fire protection system threshold requirement in Chapter 9 of the current California Building Code than exists in the current building or space . The installation of the automatic sprinkler system shall be required within the area of the change of occupancy and areas of the building not separated by a fire wall from the change of occupancy.

    1011.2.1.1 Nonrequired automatic sprinkler systems. The code official is authorized to permit the removal of an existing automatic sprinkler system where all of the following conditions exist:

    1. The system is not required for new construction.
    2. Portions of the system that are exposed to the public are removed.
    3. The system was not installed as part of any special construction features, including fire-resistance-rated assemblies and smoke-resistive assemblies, conditions of occupancy, means of egress conditions, fire code deficiencies, approved modifications or approved alternative materials, design and methods of construction, and equipment applying to the building.

    1011.2.1.1.1 Approval. Plans, investigation and evaluation reports, and other data shall be submitted documenting compliance with Section 1011.2.1.1 for review and approval in support of a determination authorizing the removal of the automatic sprinkler system by the code official.

    1011.2.2 Fire alarm and detection system. Where a change in occupancy classification occurs or where there is a change of occupancy within a space where there is a different fire protection system threshold requirement in Chapter 9 of the current Cali- fornia Building Code than exists in the current building or space that requires a fire alarm and detection system to be provided based on the new occupancy, such system shall be in accordance with Chapter 11 and Section 907 of the California Fire Code.

Frequently asked questions

Can I always avoid regular new‑construction requirements when changing occupancy in a historic building?

Not always. The CHBC says a change of occupancy for a qualified historical building does not mandate full new‑construction compliance, but the building must conform to the CHBC requirements for the new use. Distinct hazards, unsafe conditions, and statutorily required accessibility measures may still require specific corrective work. § 8-302.2, § 8-102.1.5, § 8-102.1.6.

What triggers CHBC review for an occupancy change?

A permit or approval request for work on a qualified historical building triggers CHBC review; for change of occupancy specifically see Chapter 8‑3 per § 8-102.1.3 and classification prior to permit issuance under § 8-301.2.

If I install sprinklers, will that change what CHBC requires?

Yes — the CHBC contains provisions allowing certain occupancy separations to be reduced or area limitations to be relaxed when the building is provided with an automatic sprinkler system; see § 8-302.3 and the cross reference to § 8-410.2.

Who decides whether my building qualifies as a historic building under the CHBC?

A building must be designated or determined eligible by an appropriate local or state governmental jurisdiction (registers, inventories, landmark lists). The CHBC applies only to qualified historical buildings or properties; see CHBC definitions and introductory material.

Do I need to bring the entire building up to current accessibility standards if I change occupancy?

Not necessarily. CHBC provides for alternative accessibility solutions where strict compliance would threaten historical significance; such alternatives are applied case‑by‑case with documentation (see accessibility chapter). However, some accessibility obligations are mandated and may require action. See § 8-601 and related accessibility provisions.

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