CHBC · California Historical Building Code

When is a structural survey required and what must it include?

Q: Who must perform the structural survey?

A licensed architect or engineer knowledgeable in historical structures must perform the survey as required by § 8-703.1 .

Q: Where can I find numeric strength allowances for historic masonry?

Some allowances are stated in the CHBC (for example, 9 psi ultimate shear for certain existing solid masonry under qualifying conditions — § 8-805.1 ). The survey must support use of those allowances.

If you are assessing the structural capacity of a qualified historic building under the CHBC, you must hire an architect or engineer experienced with historic structures to perform a structural survey that documents deterioration, framing, load-resisting systems, and the details/reinforcement/anchorage relied on for lateral resistance; those survey results are required to evaluate capacity and to design any necessary modifications (see **§ 8-703.1**, **§ 8-703.2**, **§ 8-703.3**).

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

When a structure or a portion of a structure is being evaluated for structural capacity under the CHBC, the building must be given a structural survey performed by an architect or engineer knowledgeable in historical structures per § 8-703.1. The survey must document deterioration or signs of distress, determine the structural framing and the system that resists gravity and lateral loads, and document details, reinforcement and anchorage where those elements are relied on for seismic lateral resistance (see § 8-703.1). The survey’s findings are used to evaluate capacity and to design any modifications needed to meet the CHBC requirements (see § 8-703.2 and § 8-703.3) .

If you are evaluating structural capacity under the CHBC, hire an architect or engineer experienced with historic structures to document damage, framing, load paths and anchorage — that record is the basis for capacity assessment and any required strengthening (per § 8-703.1).

Requirements in detail

Who must do the survey

The survey must be done by an architect or engineer knowledgeable in historical structures (bolded above) — § 8-703.1.

What the survey must evaluate and document

Deterioration or signs of distress (rot, cracking, settlement, corrosion, etc.).
Details of the structural framing (member sizes, spans, connections, species/grade if wood, presence and extent of reinforcement if masonry/concrete).
The system for resistance of gravity and lateral loads (how loads flow to foundations; whether a complete load path exists).
Details, reinforcement and anchorage of structural systems and veneers where those elements are relied upon for seismic lateral resistance (for example, veneer anchors, wall-to-floor ties, bond beams).
These items are required by § 8-703.1 and are the basis for evaluation and design under § 8-703.2.

How the survey is used

The survey results must be utilized for evaluating structural capacity and for designing modifications to bring the structure into compliance with the CHBC when work is undertaken — § 8-703.2.

Use of historical records

Past historical records of the structure or similar structures may be used as part of the evaluation, including any effects of subsequent alterations — § 8-703.3. Use of records does not eliminate the need for a physical survey where the CHBC requires one.

Decision-relevant dimensions and values (quick reference)

Decision dimension	What to look for / required value	Code Reference
Trigger for a survey	Any evaluation for structural capacity under the CHBC (i.e., when you are assessing structural safety or proposing structural work on a qualified historic building)	§ 8-703.1
Qualified professional	Architect or engineer knowledgeable in historical structures	§ 8-703.1
Survey scope — condition	Deterioration, signs of distress (document condition)	§ 8-703.1
Survey scope — systems	Structural framing; gravity and lateral load-resisting systems; details/reinforcement/anchorage where relied on for lateral resistance	§ 8-703.1
Use of results	Required for capacity evaluation and for design of modifications	§ 8-703.2
Use of records	Historical records may supplement the survey (including changes and past alterations)	§ 8-703.3
Archaic materials	Survey must document existing conditions, reinforcement, anchorage, deterioration for assigning allowable stresses	§ 8-804
Masonry shear allowance (where applicable)	Existing solid masonry may be allowed maximum ultimate shear strength of 9 psi with a qualifying professional statement (conditions apply)	§ 8-805.1

Exceptions & special cases

The CHBC text in § 8-703 does not list specific exemptions to the requirement that a survey be performed when evaluating structural capacity; the requirement applies whenever such an evaluation is made under the CHBC (§ 8-703.1) .
Historical records may be used to support the survey and fill gaps where original construction documentation exists, but records supplement rather than replace required field documentation (§ 8-703.3) .
For archaic materials (e.g., adobe, unreinforced rubble concrete, historic timber), the CHBC explicitly requires the structural survey to document conditions, reinforcement and anchorage because allowable stresses will be assigned from that information (§ 8-804) .
New nonhistorical additions that impose loads on the historic structure require evaluation of the affected supporting elements — see § 8-704.2 (the CHBC requires evaluation and strengthening if necessary) .

If you need to know whether a particular small repair or purely nonstructural work requires a formal survey under CHBC, that depends on whether the work requires an evaluation of structural capacity; the CHBC language ties the survey requirement to the evaluation for structural capacity rather than every permit submittal — refer to § 8-703.1 for scope.

Common mistakes

Hiring a professional without specific experience in historical structures. The CHBC requires an architect or engineer knowledgeable in historical structures — § 8-703.1.
Treating historical records as a substitute for a field survey. Records may be used, but they are supplemental — § 8-703.3.
Not documenting anchorage and reinforcement for veneers or decorative features that are relied on for lateral resistance; those items must be determined and documented per § 8-703.1.
Forgetting to use the survey for design. The CHBC requires the survey results to be the basis for capacity evaluation and design of modifications — § 8-703.2.
Assuming default strength values without inspection or testing for archaic materials — the CHBC requires testing or documentation from the survey to assign allowable stresses for such materials (see § 8-802 and § 8-804) .

Worked example — concrete scenario with numbers

Scenario: You are renovating a 2-story historic brick building with solid masonry exterior bearing walls. You need to evaluate whether the existing brick walls can resist the seismic shear demand after a proposed alteration.

Steps under the CHBC:

Engage an engineer knowledgeable in historical structures to perform the structural survey required by § 8-703.1. The survey documents condition, mortar quality, wall thickness and any existing ties/anchors.
The survey notes the wall is solid brick, mortar joints appear filled, and the wall is in reasonably good condition. Under § 8-805.1, such existing solid masonry may be allowed a maximum ultimate shear strength of 9 psi where a qualifying statement by the architect or engineer is provided (conditions in the section apply). Use that 9 psi as a starting allowable ultimate shear in the evaluation.

Quick numeric check (illustrative):

Wall thickness = 8 in (0.667 ft) and wall height between lateral supports = 12 ft. Tributary wall area for shear = thickness × height = 8 in × 144 in = 1,152 in².
Allowable ultimate shear at 9 psi: 9 lb/in² × 1,152 in² = 10,368 lb (≈ 10.4 kips) total shear capacity for that wall segment (ultimate).
If the engineer’s seismic analysis (using CHBC lateral provisions and appropriate methods) produces an estimated seismic shear demand on that wall of 6.0 kips, the wall’s ultimate capacity (10.4 kips) would exceed the demand; the engineer can then determine if this provides acceptable performance or if additional factors (ductility, reserve strength, partial factors, anchorage) require strengthening. The CHBC requires that the survey results be utilized for the evaluation and design of modifications — § 8-703.2.

Notes and caveats:

The CHBC’s allowance of 9 psi in § 8-805.1 is conditional — the engineer must make the appropriate inspection and statement; higher values require testing or justification. Do not assume the 9 psi universally applies without verifying the qualifying conditions and local enforcing agency concurrence.

Related provisions

§ 8-704.1–8-704.2 — Nonhistorical additions and alterations (when additions impose loads, the supporting historic structure must be evaluated and strengthened if necessary).
§ 8-705.1–8-705.2 — Structural regulations for gravity, wind and seismic loads; evaluation and strengthening objectives.
§ 8-706.3–8-706.5 — Lateral load regulations (load path, parapets, nonstructural features and their anchorage).
§ 8-802 — General engineering approaches for archaic materials (testing and assignment of strength values).
§ 8-804 — Requirement that surveys document existing conditions, reinforcement, anchorage and deterioration for archaic materials.
§ 8-805 and § 8-806 — Specific allowable conditions and strength values for masonry and adobe referenced to what the survey must document (e.g., 9 psi for certain solid masonry; 12 psi for some adobe shear limits where specified).

Code references

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

CHBC § 8-702.2 High relevance — show source text
8-702.2 Nothing in these regulations shall prevent voluntary and partial seismic upgrades when it is demonstrated that such upgrades will improve life safety and when a full upgrade would not otherwise be required.

SECTION 8-703 — STRUCTURAL SURVEY

8-703.1 Scope. When a structure or portion of a structure is to be evaluated for structural capacity under the CHBC, it shall be surveyed for structural conditions by an architect or engineer knowledgeable in historical structures. The survey shall evaluate deterioration or signs of distress. The survey shall determine the details of the structural framing and the system for resistance of gravity and lateral loads. Details, reinforcement and anchorage of structural systems and veneers shall be determined and documented where these members are relied on for seismic lateral resistance.

8-703.2 The results of the survey shall be utilized for evaluating the structural capacity and for designing modifications to the structural system to reach compliance with this code.

8-703.3 Historical records. Past historical records of the structure or similar structures may be used in the evaluation, including the effects of subsequent alterations.

SECTION 8-704 — NONHISTORICAL ADDITIONS AND NONHISTORICAL ALTERATIONS

8-704.1 New nonhistorical additions and nonhistorical alterations which are structurally separated from an existing historical building or structure shall comply with regular code requirements.

8-704.2 New nonhistorical additions which impose vertical or lateral loads on an existing structure shall not be permitted unless the affected part of the supporting structure is evaluated and strengthened, if necessary, to meet regular code requirements.

Note: For use of archaic materials, see Chapter 8-8.

SECTION 8-705 — STRUCTURAL REGULATIONS

8-705.1 Gravity loads. The capacity of the structure to resist gravity loads shall be evaluated and the structure strengthened as necessary. The evaluation shall include all parts of the load path. Where no distress is evident, and a complete load path is present, the structure may be assumed adequate by having withstood the test of time if anticipated dead and live loads will not exceed those historically present.

8-705.2 Wind and seismic loads. The ability of the structure to resist wind and seismic loads shall be evaluated. Wind loads shall be considered when appropriate, but need not exceed 75 percent of the wind loads prescribed by the regular code. The evaluation shall be based on the requirements of Section 8-706.

8.705.2.1 Any unsafe conditions in the lateral-load-resisting system shall be corrected, or alternative resistance shall be provided. When strengthening is required, additional resistance shall be provided to meet the minimum requirements of the CHBC. The strengthening measures shall be selected with the intent of meeting the performance objectives set forth in Section 8-701.2. The evaluation of structural members and structural systems for seismic loads shall consider the inelastic performance of structural members and their ability to maintain load-carrying capacity during the seismic loadings prescribed by the regular code.

8.705.2.2 The architect or engineer shall consider additional measures with minimal loss of, and impact to, historical materials which will reduce damage and needed repairs in future earthquakes to better preserve the historical structure in perpetuity. These additional measures shall be presented to the owner for consideration as part of the rehabilitation or restoration.

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STRUCTURAL REGULATIONS
CHBC § 8-7 High relevance — show source text
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8-7 STRUCTURAL REGULATIONS

SECTION 8-701 — PURPOSE, INTENT AND SCOPE

8-701.1 Purpose. The purpose of the CHBC is to provide alternative regulations to the regular code for the structural safety of buildings designated as qualified historical buildings or properties. The CHBC requires enforcing agencies to accept any reasonably equivalent alternatives to the regular code when dealing with qualified historical buildings or properties.

8-701.2 Intent. The intent of this chapter is to encourage the preservation of qualified historical buildings or structures while providing standards for a minimum level of building performance with the objective of preventing partial or total structural collapse such that the overall risk of life-threatening injury as a result of structural collapse is low.

8-701.3 Application. The alternative structural regulations provided by Section 8-705 are to be applied in conjunction with the regular code whenever a structural upgrade or reconstruction is undertaken for qualified historical buildings or properties.

SECTION 8-702 — GENERAL

8-702.1 The CHBC shall not be construed to allow the enforcing agency to approve or permit a lower level of safety of structural design and construction than that which is reasonably equivalent to the regular code provisions in occupancies which are critical to the safety and welfare of the public at large, including, but not limited to, public and private schools, hospitals, municipal police and fire stations and essential services facilities.

8-702.2 Nothing in these regulations shall prevent voluntary and partial seismic upgrades when it is demonstrated that such upgrades will improve life safety and when a full upgrade would not otherwise be required.

SECTION 8-703 — STRUCTURAL SURVEY

8-703.1 Scope. When a structure or portion of a structure is to be evaluated for structural capacity under the CHBC, it shall be surveyed for structural conditions by an architect or engineer knowledgeable in historical structures. The survey shall evaluate deterioration or signs of distress. The survey shall determine the details of the structural framing and the system for resistance of gravity and lateral loads. Details, reinforcement and anchorage of structural systems and veneers shall be determined and documented where these members are relied on for seismic lateral resistance.

8-703.2 The results of the survey shall be utilized for evaluating the structural capacity and for designing modifications to the structural system to reach compliance with this code.

8-703.3 Historical records. Past historical records of the structure or similar structures may be used in the evaluation, including the effects of subsequent alterations.

SECTION 8-704 — NONHISTORICAL ADDITIONS AND NONHISTORICAL ALTERATIONS

8-704.1 New nonhistorical additions and nonhistorical alterations which are structurally separated from an existing historical building or structure shall comply with regular code requirements.

8-704.2 New nonhistorical additions which impose vertical or lateral loads on an existing structure shall not be permitted unless the affected part of the supporting structure is evaluated and strengthened, if necessary, to meet regular code requirements.

Note: For use of archaic materials, see Chapter 8-8.

SECTION 8-705 — STRUCTURAL REGULATIONS
CHBC § 8-804 High relevance — show source text
SECTION 8-804 — ALLOWABLE CONDITIONS FOR SPECIFIC MATERIALS

Archaic materials which exist and are to remain in qualified historical buildings or structures shall be evaluated for their condition and for loads required by this code. The structural survey required in Section 8-703 of the CHBC shall document existing conditions, reinforcement, anchorage, deterioration and other factors pertinent to establishing allowable stresses, strength levels and adequacy of the archaic materials. The remaining portion of this chapter provides additional specific requirements for commonly encountered archaic materials.

SECTION 8-805 — MASONRY

For adobe, see Section 8-806.

8-805.1 Existing solid masonry. Existing solid masonry walls of any type, except adobe, may be allowed, without testing, a maximum ultimate strength of 9 pounds per square inch (62.1 kPa) in shear where there is a qualifying statement by the architect or engineer that an inspection has been made, that mortar joints are filled and that both brick and mortar are reasonably good. The shear stress above applies to unreinforced masonry, except adobe, where the maximum ratio of unsupported height or length to thickness does not exceed 13, and where minimum quality mortar is used or exists. Wall height or length is measured to supporting or resisting elements that are at least twice as stiff as the tributary wall. Stiffness is based on the gross section. Shear stress may be increased by the addition of 10 percent of the axial direct stress due to the weight of the wall directly above. Higher-quality mortar may provide a greater shear value and shall be tested in accordance with Appendix A, Chapter A1 of the California Existing Building Code (CEBC) 2010 edition, and as modified by the CHBC.

8-805.2 Stone masonry.

8-805.2.1 Solid-backed stone masonry. Stone masonry solidly backed with brick masonry shall be treated as solid brick masonry as described in Section 8-805.1 and in the 2009 International Existing Building Code [®] (IEBC [®] ), provided representative testing and inspection verifies solid collar joints between stone and brick and that a reasonable number of stones lap with the brick wythes as headers or that steel anchors are present. Solid stone masonry where the wythes of stone effectively overlap to provide the equivalent header courses may also be treated as solid brick masonry.

8-805.2.2 Independent wythe stone masonry. Stone masonry with independent face wythes may be treated as solid brick masonry as described in Section 8-805.1 and the CEBC, provided representative testing and inspection verify that the core is essentially solid in the masonry wall and that steel ties are epoxied in drilled holes between outer stone wythes at floors, roof and not to exceed 4 feet (1219 mm) on center in each direction, between floors and roof. A reinforcing element shall exist or be provided at or near the top of all stone masonry walls.

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ARCHAIC MATERIALS AND METHODS OF CONSTRUCTION

8-805.2.3 Testing of stone masonry. Testing of stone masonry shall be similar to the 2010 CEBC requirements for brick masonry, except that representative stones which are not interlocked shall be pulled outward from the wall and shear area appropriately calculated after the test.
CHBC § 8-6 High relevance — show source text
CHAPTER 8-6 ACCESSIBILITY . . . . . . . . . . . . . . . . . . . . . . . . 11

Section

8-601 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 11

8-602 Basic Provisions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8-603 Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8-604 Equivalent Facilitation. . . . . . . . . . . . . . . . . . . . . . . . . . 12

CHAPTER 8-7 STRUCTURAL REGULATIONS. . . . . . . . . . . . . 13

Section

8-701 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 13 8-702 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

8-703 Structural Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8-704 Nonhistorical Additions and

Nonhistorical Alterations . . . . . . . . . . . . . . . . . . . . . . . 13

8-705 Structural Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8-706 Lateral Load Regulations. . . . . . . . . . . . . . . . . . . . . . . . 14

CHAPTER 8-8 ARCHAIC MATERIALS AND METHODS OF

CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . 15

Section

8-801 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 15 8-802 General Engineering Approaches. . . . . . . . . . . . . . . . . 15 8-803 Nonstructural Archaic Materials. . . . . . . . . . . . . . . . . . 15

8-804 Allowable Conditions for Specific Materials . . . . . . . 15 8-805 Masonry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 8-806 Adobe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

8-807 Wood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

8-808 Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
CHBC § 4.3. Medium relevance — show source text
4.3. Ground stabilization.

4.4. Any combination of these measures and how they shall be considered in the design of the structure.

1803.6 Reporting. Where geotechnical investigations are required, a written report of the investigations shall be submitted to the building official by the permit applicant at the time of permit application. This geotechnical report shall include, but need not be limited to, the following information:
1. A plot showing the location of the soil investigations.
2. A complete record of the soil boring and penetration test logs and soil samples.
3. A record of the soil profile.
4. Elevation of the water table, if encountered.
5. Recommendations for foundation type and design criteria, including but not limited to: bearing capacity of natural or compacted soil; provisions to mitigate the effects of expansive soils; mitigation of the effects of liquefaction, differential settlement and varying soil strength; and the effects of adjacent loads.
6. Expected total and differential settlement.
7. Deep foundation information in accordance with Section 1803.5.5.
8. Special design and construction provisions for foundations of structures founded on expansive soils, as necessary.
9. Compacted fill material properties and testing in accordance with Section 1803.5.8.
10. Controlled low-strength material properties and testing in accordance with Section 1803.5.9. 11. [OSHPD 1R, 2 & 5] The report shall consider the effects of seismic hazard in accordance with Section 1803.7.
1803.7 Geohazard reports. [OSHPD 1R, 2 & 5] Geohazard reports shall be required for all proposed construction.

Exceptions: 1. Reports are not required for one-story, wood-frame and light-steel-frame buildings of Type V skilled nursing or intermediate care facilities construction and 4,000 square feet (371 m [2] ) or less in floor area, not located within Earthquake Fault Zones or Seismic Hazard Zones as shown in the most recently published maps from the California Geological Survey (CGS); 2. Reports are not required for the following scopes of work in existing buildings:

Nonstructural alterations, voluntary structural alterations without foundation work, and incidental structural additions or alterations, and structural repairs for other than earthquake damage. 3. A previous report for a specific site may be resubmitted, provided that a reevaluation is made and the report is found to be currently appropriate.

The purpose of the geohazard report shall be to identify geologic and seismic conditions that may require project mitigations. The reports shall contain data which provide an assessment of the nature of the site and potential for earthquake damage based on appropriate investigations of the regional and site geology, project foundation conditions and the potential seismic shaking at the site. The report shall be prepared by a California-certified engineering geologist in consultation with a California-registered geotech- nical engineer.

The preparation of the geohazard report shall consider the most recent CGS Note 48; Checklist for the Review of Engineering Geol- ogy and Seismology Reports for California Public School, Hospitals and Essential Services Buildings. In addition, the most recent version of CGS Special Publication 42: Earthquake Fault Zones, A Guide for Government Agencies, Property Owners / Developers, and Geoscience Practitioners for Assessing Fault Rupture Hazards in California, shall be considered for project sites proposed within an _Alquist-Priolo Earthquake Fault Zone.
CHBC § 8-801 Medium relevance — show source text
SECTION 8-801 — PURPOSE, INTENT AND SCOPE

8-801.1 Purpose. The purpose of the CHBC is to provide regulations for the use of historical methods and materials of construction that are at variance with regular code requirements or are not otherwise codified, in buildings or structures designated as qualified historical buildings or properties. The CHBC require enforcing agencies to accept any reasonably equivalent alternatives to the regular code when dealing with qualified historical buildings or properties.

8-801.2 Intent. It is the intent of the CHBC to provide for the use of historical methods and materials of construction that are at variance with specific code requirements or are not otherwise codified.

8-801.3 Scope. Any construction type or material that is, or was, part of the historical fabric of a structure is covered by this chapter. Archaic materials and methods of construction present in a historical structure may remain or be reinstalled or be installed with new materials of the same class to match existing conditions.

SECTION 8-802 — GENERAL ENGINEERING APPROACHES

Strength values for archaic materials shall be assigned based upon similar conventional codified materials, or on tests as hereinafter indicated. The archaic materials and methods of construction shall be thoroughly investigated for their details of construction in accordance with Section 8-703. Testing shall be performed when applicable to evaluate existing conditions. The architect or structural engineer in responsible charge of the project shall assign allowable stresses or strength levels to archaic materials. Such assigned strength values shall not be greater than those provided for in the following sections without adequate testing, and shall be subject to the concurrence of the enforcing agency.

SECTION 8-803 — NONSTRUCTURAL ARCHAIC MATERIALS

Where nonstructural historical materials exist in uses which do not meet the requirements of the regular code, their continued use is allowed by this code, provided that any public health and life safety hazards are mitigated subject to the concurrence of the enforcing agency.

SECTION 8-804 — ALLOWABLE CONDITIONS FOR SPECIFIC MATERIALS

Archaic materials which exist and are to remain in qualified historical buildings or structures shall be evaluated for their condition and for loads required by this code. The structural survey required in Section 8-703 of the CHBC shall document existing conditions, reinforcement, anchorage, deterioration and other factors pertinent to establishing allowable stresses, strength levels and adequacy of the archaic materials. The remaining portion of this chapter provides additional specific requirements for commonly encountered archaic materials.

SECTION 8-805 — MASONRY

For adobe, see Section 8-806.

8-805.1 Existing solid masonry. Existing solid masonry walls of any type, except adobe, may be allowed, without testing, a maximum ultimate strength of 9 pounds per square inch (62.1 kPa) in shear where there is a qualifying statement by the architect or engineer that an inspection has been made, that mortar joints are filled and that both brick and mortar are reasonably good. The shear stress above applies to unreinforced masonry, except adobe, where the maximum ratio of unsupported height or length to thickness does not exceed 13, and where minimum quality mortar is used or exists. Wall height or length is measured to supporting or resisting elements that are at least twice as stiff as the tributary wall. Stiffness is based on the gross section. Shear stress may be increased by the addition of 10 percent of the axial direct stress due to the weight of the wall directly above.
CHBC § 8-604 Medium relevance — show source text
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ACCESSIBILITY

SECTION 8-604 — EQUIVALENT FACILITATION

Use of other designs and technologies, or deviation from particular technical and scoping requirements, are permitted if the application of the alternative provisions contained in Section 8-603 would threaten or destroy the historical significance or characterdefining features of the historical building or property.
1. Such alternatives shall be applied only on an item-by- item or a case-by-case basis.
2. Access provided by experiences, services, functions, materials and resources through methods including, but not limited to, maps, plans, videos, virtual reality and related equipment, at accessible levels. The alternative design and/or technologies used will provide substantially equivalent or greater accessibility to, and usability of, the facility.
3. The official charged with the enforcement of the standards shall document the reasons for the application of the design and/or technologies and their effect on the historical significance or character-defining features. Such documentation shall be in accordance with Section 8-602.2, Item 2, and shall include the opinion and comments of state or local accessibility officials, and the opinion and comments of representative local groups of people with disabilities. Such documentation shall be retained in the permanent file of the enforcing agency. Copies of the required documentation should be available at the facility upon request.
Note: For commercial facilities and places of public accommodation (Title III entities).

Equivalent facilitation for an element of a building or property when applied as a waiver of an ADA accessibility requirement will not be entitled to the Federal Department of Justice certification of this code as rebuttable evidence of compliance for that element.

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8-7 STRUCTURAL REGULATIONS

SECTION 8-701 — PURPOSE, INTENT AND SCOPE

8-701.1 Purpose. The purpose of the CHBC is to provide alternative regulations to the regular code for the structural safety of buildings designated as qualified historical buildings or properties. The CHBC requires enforcing agencies to accept any reasonably equivalent alternatives to the regular code when dealing with qualified historical buildings or properties.

8-701.2 Intent. The intent of this chapter is to encourage the preservation of qualified historical buildings or structures while providing standards for a minimum level of building performance with the objective of preventing partial or total structural collapse such that the overall risk of life-threatening injury as a result of structural collapse is low.

8-701.3 Application. The alternative structural regulations provided by Section 8-705 are to be applied in conjunction with the regular code whenever a structural upgrade or reconstruction is undertaken for qualified historical buildings or properties.

SECTION 8-702 — GENERAL

8-702.1 The CHBC shall not be construed to allow the enforcing agency to approve or permit a lower level of safety of structural design and construction than that which is reasonably equivalent to the regular code provisions in occupancies which are critical to the safety and welfare of the public at large, including, but not limited to, public and private schools, hospitals, municipal police and fire stations and essential services facilities.

8-702.2 Nothing in these regulations shall prevent voluntary and partial seismic upgrades when it is demonstrated that such upgrades will improve life safety and when a full upgrade would not otherwise be required.
CHBC § 8-408 Medium relevance — show source text
8-408 Roof Covering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8-409 Fire Alarm Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 8-410 Automatic Sprinkler Systems. . . . . . . . . . . . . . . . . . . . . 8 8-411 Other Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 8-412 High-rise Buildings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

CHAPTER 8-5 MEANS OF EGRESS . . . . . . . . . . . . . . . . . . . . . . 9

Section

8-501 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . . 9 8-502 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

8-503 Escape or Rescue Windows and Doors. . . . . . . . . . . . 10 8-504 Railings and Guardrails . . . . . . . . . . . . . . . . . . . . . . . . . 10

CHAPTER 8-6 ACCESSIBILITY . . . . . . . . . . . . . . . . . . . . . . . . 11

Section

8-601 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 11

8-602 Basic Provisions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8-603 Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8-604 Equivalent Facilitation. . . . . . . . . . . . . . . . . . . . . . . . . . 12

CHAPTER 8-7 STRUCTURAL REGULATIONS. . . . . . . . . . . . . 13

Section

8-701 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 13 8-702 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

8-703 Structural Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8-704 Nonhistorical Additions and

Nonhistorical Alterations . . . . . . . . . . . . . . . . . . . . . . . 13
CHBC § 323-9843 Medium relevance — show source text
State Librarian [SL]

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

2025 CALIFORNIA HISTORICAL BUILDING CODE v

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

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vi 2025 CALIFORNIA HISTORICAL BUILDING CODE

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

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 § 2.5. Medium relevance — show source text
1705 A .10 Structural integrity of deep foundation elements. Whenever there is a reasonable doubt as to the structural integrity of a deep foundation element, an engineering assessment shall be required. The engineering assessment shall include tests for defects performed in accordance with ASTM D4945, ASTM D5882, ASTM D6760 or ASTM D7949, or other approved method.

1705 A .11 Fabricated items. Special inspections of fabricated items shall be performed in accordance with Section 1704 A .2.5.

1705 A .12 Special inspections for wind resistance. Special inspections for wind resistance specified in Sections 1705 A .12.1 through 1705 A .12.3, unless exempted by the exceptions to Section 1704 A .2, are required for buildings and structures constructed in the following areas:
1. In wind Exposure Category B, where basic wind speed, V, is 150 mph (67 m/sec) or greater.
2. In wind Exposure Category C or D, where basic wind speed, V, is 140 mph (62.6 m/sec) or greater.
1705 A .12.1 Structural wood. Continuous special inspection is required during field gluing operations of elements of the main windforce-resisting system. Periodic special inspection is required for nailing, bolting, anchoring and other fastening of elements of the main windforce-resisting system, including wood shear walls, wood diaphragms, drag struts, braces and hold-downs.

1705 A .12.2 Cold-formed steel light-frame construction. Periodic special inspection is required for welding operations of elements of the main windforce-resisting system. Periodic special inspection is required for screw attachment, bolting, anchoring and other fastening of elements of the main windforce-resisting system, including shear walls, braces, diaphragms, collectors (drag struts) and hold-downs. [DSA-SS, DSA-SS/CC] Requirements specified in Section 1705A.2.9 shall also apply.

1705 A .12.3 Wind-resisting components. Periodic special inspection is required for fastening of the following systems and components:
1. Roof covering, roof deck and roof framing connections.
2. Exterior wall covering and wall connections to roof and floor diaphragms and framing.
1705 A .13 Special inspections for seismic resistance. Special inspections for seismic resistance shall be required as specified in Sections 1705 A .13.1 through 1705 A .13.9, unless exempted by the exceptions of Section 1704 A .2.

1705 A .13.1 Structural steel. Special inspections for seismic resistance shall be in accordance with Section 1705 A .13.1.1 or 1705 A .13.1.2, as applicable.

1705 A .13.1.1 Seismic force-resisting systems. Special inspections of structural steel in the seismic force-resisting systems in buildings and structures assigned to Seismic Design Category D, E or F shall be performed in accordance with the quality assurance requirements of AISC 341 and this code.
CHBC § 1705.10 Medium relevance — show source text
1705.10 Structural integrity of deep foundation elements. Whenever there is a reasonable doubt as to the structural integrity of a deep foundation element, an engineering assessment shall be required. The engineering assessment shall include tests for defects performed in accordance with ASTM D4945, ASTM D5882, ASTM D6760 or ASTM D7949, or other approved method.

1705.11 Fabricated items. Special inspections of fabricated items shall be performed in accordance with Section 1704.2.5.

1705.12 Special inspections for wind resistance. Special inspections for wind resistance specified in Sections 1705.12.1 through 1705.12.3, unless exempted by the exceptions to Section 1704.2, are required for buildings and structures constructed in the following areas:
1. In wind Exposure Category B, where basic wind speed, V, is 150 mph (67 m/sec) or greater.
2. In wind Exposure Category C or D, where basic wind speed, V, is 140 mph (62.6 m/sec) or greater.
1705.12.1 Structural wood. Continuous special inspection is required during field gluing operations of elements of the main windforce-resisting system. Periodic special inspection is required for nailing, bolting, anchoring and other fastening of elements of the main windforce-resisting system, including wood shear walls, wood diaphragms, drag struts, braces and hold-downs.

Exception: Special inspections are not required for wood shear walls, shear panels and diaphragms, including nailing, bolting, anchoring and other fastening to other elements of the main windforce-resisting system, where the lateral resistance is provided by structural sheathing and the specified fastener spacing at panel edges is more than 4 inches (102 mm) on center.

1705.12.2 Cold-formed steel light-frame construction. Periodic special inspection is required for welding operations of elements of the main windforce-resisting system. Periodic special inspection is required for screw attachment, bolting, anchoring and other fastening of elements of the main windforce-resisting system, including shear walls, braces, diaphragms, collectors (drag struts) and hold-downs.

Exception: Special inspections are not required for cold-formed steel light-frame shear walls and diaphragms, including screwing, bolting, anchoring and other fastening to components of the windforce-resisting system, where either of the following applies:
1. The sheathing is gypsum board or fiberboard.
2. The sheathing is wood structural panel or steel sheets on only one side of the shear wall, shear panel or diaphragm assembly and the specified fastener spacing at the panel or sheet edges is more than 4 inches (102 mm) on center (o.c.).
1705.12.3 Wind-resisting components. Periodic special inspection is required for fastening of the following systems and components:
1. Roof covering, roof deck and roof framing connections.
2. Exterior wall covering and wall connections to roof and floor diaphragms and framing.
1705.13 Special inspections for seismic resistance. Special inspections for seismic resistance shall be required as specified in Sections 1705.13.1 through 1705.13.9, unless exempted by the exceptions of Section 1704.2.

Exception: The special inspections specified in Sections 1705.13.1 through 1705.13.9 are not required for structures designed and constructed in accordance with one of the following: 1.

CHBC § 2.1 Medium relevance — show source text

Roofs. The preliminary field survey of the roof system is initially concerned with watertightness. However, once it is apparent that the roof is sound for ordinary use and can be retained in the rehabilitated building, it becomes necessary to evaluate the fire performance. The field investigator must measure the thickness and identify the types of materials which have been used. Be aware that there may be several layers of roof materials.

Doors. Doors to stairways and hallways represent some of the most important fire elements to be considered within a building. The uses of the spaces separated largely controls the level of fire performance necessary. Walls and doors enclosing stairways or elevator shafts would normally require a higher level of performance than between the bedroom and bath. The various uses are differentiated in Table 2.1(1).

Careful measurements of the thickness of door panels must be made, and the type of core material within each door must be determined. It should be noted whether doors have self-closing devices; the general operation of the doors should be checked. The latch should engage and the door should fit tightly in the frame. The hinges should be in good condition. If glass is used in the doors, it should be identified as either plain glass or wired glass mounted in either a wood or steel frame.

Materials. The field investigator should be able to identify ordinary building materials. In situations where an unfamiliar material is found, a sample should be obtained. This sample should measure at least 10 cubic inches so that an ASTM E136 fire test can be conducted to determine if it is combustible.

Thickness. The thickness of all materials should be measured accurately since, under certain circumstances, the level of fire resistance is very sensitive to the material thickness.

Condition. The method of attaching the various layers and facings to one another or to the supporting structural element should be noted under the appropriate building element. The “secureness” of the attachment and the general condition of the layers and facings should be noted here.

Notes. The “Notes” column can be used for many purposes, but it might be a good idea to make specific references to other field notes or drawings.

After the building survey is completed, the data collected must be analyzed. A suggested work sheet for organizing this information is given as Table 2.1(2).

RESOURCE A-6 2025 CALIFORNIA EXISTING BUILDING CODE

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

RESOURCE A—GUIDELINES ON FIRE RATINGS OF ARCHAIC MATERIALS AND ASSEMBLIES

TABLE 2.1(1) PRELIMINARY EVALUATION FIELD NOTES	Col2	Col3	Col4	Col5	Col6
BUILDING ELEMENT	BUILDING ELEMENT	MATERIALS	THICKNESS	CONDITION	NOTES
Exterior Bearing Walls	Exterior Bearing Walls
Interior Bearing Walls	Interior Bearing Walls
Exterior Nonbearing Walls	Exterior Nonbearing Walls
Interior Nonbearing Walls or Partitions	A
Interior Nonbearing Walls or Partitions	B
Structural Frame: Columns	Structural Frame: Columns
Beams	Beams
Other	Other
Floor/Ceiling Structural System: Spanning	Floor/Ceiling Structural System: Spanning
Roofs	Roofs
Doors (including frame and

Frequently asked questions

Who must perform the structural survey?

A licensed architect or engineer knowledgeable in historical structures must perform the survey as required by § 8-703.1.

Is a field inspection always required if I have original drawings?

Historical records can be used to supplement the evaluation, but the CHBC requires a survey documenting current conditions when evaluating structural capacity — records do not automatically replace field observation (§ 8-703.3).

What if my building uses archaic materials like adobe?

The structural survey must specifically document existing conditions, reinforcement, anchorage and deterioration for archaic materials so allowable stresses can be assigned (see § 8-804 and related archaic material sections).

Can the survey results be used to avoid strengthening?

The survey is the basis for the capacity evaluation and design. If the documented condition and calculated capacity meet CHBC performance objectives, strengthening may not be required; otherwise the survey will guide required modifications per § 8-703.2.

Where can I find numeric strength allowances for historic masonry?

Some allowances are stated in the CHBC (for example, 9 psi ultimate shear for certain existing solid masonry under qualifying conditions — § 8-805.1). The survey must support use of those allowances.

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Related in the CHBC

How should deterioration, framing details and the load path be documented?

When can historical records or material testing be used to establish capacity?

Structural survey & assessment

California Historical Building Code