CEBC · California Existing Building Code
What structural (live load, risk category) checks are required for a change of occupancy?
If you change how space is used, the CEBC requires re-checking the structure: recalculate live loads for the changed area using the California Building Code tables, and if the building’s assigned risk category goes up, apply the higher snow and wind load rules — small increases (≤5% demand‑capacity) or small areas (<10% of the building) have limited exceptions but cumulative changes count.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
A change of occupancy triggers structural checks for both live loads and for increases in risk category. The California Existing Building Code requires that areas undergoing a change of occupancy have structural elements carrying the changed tributary live loads evaluated per the California Building Code, § 1607, as invoked by § 1006.1 of the CEBC. If the change of occupancy assigns the building to a higher risk category, the structure must satisfy the snow and wind provisions of the California Building Code for that higher risk category (Sections 1608 and 1609) as required by § 1006.2 of the CEBC.
The single most important rule: when occupancy changes, re-evaluate the live-load demands for the affected areas and, if the building’s risk category goes up, apply the higher snow/wind load requirements called up by the CEBC.
Requirements in detail
Live-load checks (what to check)
- The CEBC requires that structural elements carrying tributary live loads from the area with a change of occupancy be made to satisfy the requirements of CBC § 1607, and that design live loads for areas of new occupancy be based on CBC § 1607, per § 1006.1.
- Existing areas not part of the change may continue to use previously approved design live loads unless the affected elements are carrying tributary loads from the changed area. Defined term: tributary live load refers to the portion of live load attributed to a structural element by the area it supports.
Risk-category and snow/wind checks (when they apply)
- If the change of occupancy results in assignment to a higher risk category, the structure must comply with the CBC provisions for snow and wind for the new risk category (CBC §§ 1608, 1609), as required by § 1006.2.
- The CEBC explicitly ties the risk-category trigger to performing the higher risk-category load checks; it is not automatic for all occupancy changes — it applies when the building’s assigned risk category increases.
Key thresholds and exceptions (decision table)
| Decision dimension | Threshold / value | Action required | Code Reference |
|---|---|---|---|
| Change-of-area proportion exempt from risk-category snow/wind check | Less than 10 percent of the building area | Snow/wind check not required for the change (but cumulative changes still considered) | § 1006.2 |
| Live-load demand increase tolerance (demand-capacity ratio) | Not more than 5 percent increase | No live-load upgrade required for that element | § 1006.1 |
| New-occupancy live-load basis | Use CBC § 1607 design values | Apply CBC § 1607 live-load values to areas of new occupancy | § 1006.1 |
| Risk-category increase | Any assignment to a higher risk category | Apply CBC §§ 1608, 1609 (snow & wind) for new risk category | § 1006.2 |
| Cumulative small changes | Multiple small changes over time | Consider cumulative effect before applying exemptions | § 1006.2 (exception language) |
(Notes: the CEBC invokes the CBC for the specific load tables and values; the CEBC sections themselves set the triggers, tolerances, and exceptions summarized above.)
Exceptions & special cases
- Small-area exception: If the new occupancy area is less than 10 percent of the building area, the snow/wind requirement of § 1006.2 is not required — but the CEBC says the cumulative effect of occupancy changes must be considered (don’t repeatedly rely on many small changes to avoid triggers).
- Small-demand increase exception: If an element’s demand‑to‑capacity ratio increases by no more than 5 percent when accounting for the new occupancy live load, that element need not be upgraded per § 1006.1.
- The CEBC text here invokes other CBC sections (e.g., § 1607, § 1608, § 1609) for numeric load values and methods; consult those CBC sections for the exact live‑load psf values and wind/snow determination procedures referenced by § 1006.1 and § 1006.2. The CEBC sections themselves do not restate those numeric tables.
Common mistakes
- Treating the 10 percent area exception as a per‑project allowance without checking prior changes (ignoring cumulative changes). The CEBC explicitly requires considering cumulative effect. § 1006.2.
- Forgetting to base the new-occupancy live-load on CBC § 1607; some practitioners incorrectly re-use older “approved” loads even for newly assigned occupancies where the CEBC directs use of CBC § 1607 (see § 1006.1).
- Misapplying the 5 percent tolerance: it is a comparison of the demand-capacity ratio (not merely a percentage increase in applied load). Verify structural capacity versus new demand, then compute the ratio change per § 1006.1.
- Overlooking that risk-category increases also implicate other load systems (seismic, nonstructural) elsewhere in the CEBC — risk-category change is a broad trigger beyond just snow/wind. See Related Provisions below.
Worked example — concrete scenario
Scenario: An existing office area (current assumed design live load: 50 psf for example purposes) is being converted to an assembly use where the (example) design live load for the new use would be 100 psf. A single floor beam currently supports a tributary area that imposes 1,000 ft² of live-load on that beam.
Step 1 — Compute previous demand (example numbers)
- Previous live load = 50 psf × 1,000 ft² = 50,000 lb (this is an assumed example; actual code values must come from CBC § 1607).
Step 2 — Compute new demand - New live load = 100 psf × 1,000 ft² = 100,000 lb.
Step 3 — Compare demand-capacity ratio change - Suppose the beam’s rated capacity under prior design resulted in a demand/capacity ratio of 0.60 (i.e., demand was 60% of capacity). Under the new demand that ratio becomes 100,000 / capacity. If capacity = 83,333 lb, prior ratio = 50,000/83,333 = 0.60; new ratio = 100,000/83,333 = 1.20 — a (1.20 − 0.60)/0.60 = 100% increase in the demand/capacity ratio, which is far greater than 5 percent.
Conclusion: The 5 percent tolerance in § 1006.1 is exceeded, so the beam must be evaluated and upgraded as necessary, and the new occupancy live loads must be taken from CBC § 1607.
Worked-example notes:
- The numeric live‑load psf values above are illustrative; the CEBC mandates using CBC § 1607 for the official design live loads when applying § 1006.1. Always pull the actual live‑load values and combinations from CBC § 1607.
Related provisions (CEBC sections)
- § 1006.1 — Live loads: requires use of CBC § 1607 and provides the 5 percent demand‑capacity tolerance.
- § 1006.2 — Snow and wind loads: requires applying CBC §§ 1608 and 1609 when the risk category increases; includes the 10 percent area exception and cumulative-change language.
- § 1006.3 — Seismic loads: change-of-occupancy triggers for lateral force-resisting system upgrades when risk category increases (see CEBC § 1006.3).
- § 506.5.1 — (Chapter 5 prescriptive method) Live loads for change of occupancy, including the 5% demand‑capacity exception in that chapter’s language.
- § 506.5.2 — (Chapter 5 prescriptive method) Snow and wind load triggers and the less-than-10-percent area exception.
- CBC § 1607, § 1608, § 1609 — These California Building Code sections provide the numeric live‑load tables and methods for snow and wind that are called up by CEBC §§ 1006.1–1006.2 (consult the CBC for the exact load values and procedures).
(If you need the CBC tables and the exact psf values or wind/snow calculation methods, I can fetch the relevant CBC sections and show the specific numbers and load maps.)
Code references
Grounded in the retrieved California Existing Building Code — click a citation to read the verbatim passage:
CEBC § 506.5.1 High relevance — show source text
[BS] 506.5.1 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 need not comply with this section.
[BS] 506.5.2 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.
Exception: Where the area of the new occupancy is less than 10 percent of the building area, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
[BS] 506.5.3 Seismic loads (seismic force-resisting system). Where a change of occupancy results in a building being assigned to a higher risk category, or where the change is from a Group S or Group U occupancy to any occupancy other than Group S or
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Group U, the lateral force-resisting system of the building shall comply with Section 304.3.1 for the new risk category. Where a change of occupancy results in a building being assigned to Risk Category IV and Seismic Design Category D or F, nonstructural components serving any portion of the building changed to Risk Category IV shall comply with the requirements of Section 1613 of the California Building Code or shall comply with ASCE 41 using an objective of Operational nonstructural performance with the BSE-1N earthquake hazard level.
Exceptions:
- 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.
- 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.
- 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.
- 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.
CEBC § 1006.3 High relevance — show source text
Exception: Where the area of the new occupancy is less than 10 percent of the building area. The cumulative effect of occupancy changes over time shall be considered.
[BS] 1006.3 Seismic loads. Where a change of occupancy results in a building being assigned to a higher risk category, or where the change is from a Group S or Group U occupancy to any occupancy other than Group S or Group U, the lateral force-resisting system of the building shall comply with Section 304.3.1 for the new risk category. Where a change of occupancy results in a building being assigned to Risk Category IV and Seismic Design Category D or F, nonstructural components serving any portion of the building changed to Risk Category IV shall comply with the requirements of Section 1613 of the California Building Code or shall comply with ASCE 41 using an objective of operational nonstructural performance with the BSE-1N earthquake hazard level.
Exceptions:
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.
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.
Reserved.
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] 1006.4 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 Risk Category IV 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.
SECTION 1007—ELECTRICAL
1007.1 Special occupancies. Where the occupancy of an existing building or part of an existing building is changed to one of the following special occupancies as described in the California Electrical Code, the electrical wiring and equipment of the building or portion thereof that contains the proposed occupancy shall comply with the applicable requirements of the California Electrical Code :
Hazardous locations.
Commercial garages, repair and storage.
Aircraft hangars.
Gasoline dispensing and service stations.
Bulk storage plants.
Spray application, dipping and coating processes.
Reserved.
Places of assembly.
Theaters, audience areas of motion picture and television studios, and similar locations.
Motion picture and television studios and similar locations.
Motion picture projectors.
Agricultural buildings.
1007.2 Unsafe conditions. Where the occupancy of an existing building or part of an existing building is changed, all unsafe conditions shall be corrected without requiring that all parts of the electrical system comply with the California Electrical Code .
1007.3 Service upgrade. Where the occupancy of an existing building or part of an existing building is changed, electrical service shall be upgraded to meet the requirements of the California Electrical Code for the new occupancy.
CEBC § 1.1 High relevance — show source text
Exception: The building need not be made to comply with Chapter 16 A of the California Building Code unless required by Section 506 A .5.
506 A .1.1 Change in function . A change in function shall require compliance with all the functional requirements for new construc- tion in the California Building Code, including requirements in California Building Code Section 1224. Compliance shall be only as necessary to meet the specific provisions and is not intended to require the entire building be brought into compliance.
Exception: Minimum room clearances, areas and dimensions may meet the requirements of the 2001 California Building Code for existing rooms re-used for a similar purpose, subject to the approval of OSHPD.
506 A .2 Certificate of occupancy. A certificate of occupancy shall be issued where it has been determined that the requirements for the new occupancy classification have been met.
506 A .3 Stairways. An existing stairway shall not be required to comply with the requirements of Section 1011 of the California Build- ing Code where the existing space and construction does not allow a reduction in pitch or slope.
506 A .4 Existing emergency escape and rescue openings. Where a change of occupancy would require an emergency escape and rescue opening in accordance with Section 1031.1 of the California Building Code, operable windows serving as the emergency escape and rescue opening shall comply with the following:
- An existing operable window shall provide a minimum net clear opening of 4 square feet (0.38 m [2] ) with a minimum net clear opening height of 22 inches (559 mm) and a minimum net clear opening width of 20 inches (508 mm).
- A replacement window where such window complies with both of the following: 2.1. The replacement window meets the size requirements in Item 1. 2.2. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
506 A .5 Structural. Any building undergoing a change of occupancy shall satisfy the requirements of this section.
506 A .5.1 Live loads. Structural elements carrying tributary live loads from an area with a change of occupancy shall satisfy the requirements of Section 1607 A of the California Building Code . Design live loads for areas of new occupancy shall be based on Section 1607 A 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 need not comply with this section.
506 A .5.2 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 A and 1609 A of the California Building Code for the new risk category.
Exception: Where the area of the new occupancy is less than 10 percent of the building area, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
CEBC § 2.1. High relevance — show source text
- A replacement window where such window complies with both of the following: 2.1. The replacement window meets the size requirements in Item 1. 2.2. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
506 A .5 Structural. Any building undergoing a change of occupancy shall satisfy the requirements of this section.
506 A .5.1 Live loads. Structural elements carrying tributary live loads from an area with a change of occupancy shall satisfy the requirements of Section 1607 A of the California Building Code . Design live loads for areas of new occupancy shall be based on Section 1607 A 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 need not comply with this section.
506 A .5.2 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 A and 1609 A of the California Building Code for the new risk category.
Exception: Where the area of the new occupancy is less than 10 percent of the building area, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
506 A .5.3 Seismic loads (seismic force-resisting system). Where a change of occupancy results in a building being assigned to a higher risk category, the lateral force-resisting system of the building shall comply with the California Building Code Section 1613A or Section 304A.3.4 of this code for the new risk category. Where a change of occupancy results in a building being assigned to Risk Category IV and Seismic Design Category D or F, nonstructural components serving any portion of the building changed to Risk Category IV shall comply with the requirements of Section 1613 A of the California Building Code or shall comply with ASCE 41 -23 using an objective of Operational nonstructural performance with the BSE-1N earthquake hazard level.
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CALIFORNIA EXISTING BUILDING CODE – MATRIX ADOPTION TABLE
CHAPTER 6 – CLASSIFICATION OF WORK
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
CEBC § 1.1 High relevance — show source text
Exception: In-filling of floor openings and nonoccupiable appendages such as elevator and exit stairway shafts shall be permitted beyond that permitted by the California Building Code.
502 A .1.1 Risk category assignment. Where the addition and the existing building have different occupancies, the risk category of each existing and added occupancy shall be determined in accordance with Section 1604 A .5.1 of the California Building Code . Where application of that section results in a higher risk category for the existing building compared with the risk category for the existing building before the addition, such a change shall be considered a change of occupancy and shall comply with Section 506 A of this code. Where application of that section results in a higher risk category for the addition compared with the risk category for the addition by itself, the addition and any systems in the existing building required to serve the addition shall comply with the requirements of the California Building Code for new construction for the higher risk category.
502 A .1.2 Creation or extension of nonconformity. An addition shall not create or extend any nonconformity in the existing building to which the addition is being made with regard to accessibility, structural strength, supports and attachments for nonstructural components, fire safety, means of egress or the capacity of mechanical, plumbing or electrical systems.
Exception: Nonconforming supports and attachments for nonstructural components that serve the addition from within the existing building need not be altered to comply with California Building Code Section 1613 A unless the components are part of the addition’s life-safety system or are required to serve an addition assigned to Risk Category IV.
502 A .2 Flood hazard areas. For buildings and structures in flood hazard areas established in California Building Code, Section 1612 A .3, any addition that constitutes substantial improvement of the existing structure , as defined in Chapter 2, shall comply with the flood design requirements for new construction, and all aspects of the existing structure shall be brought into compliance with
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the requirements for new construction for flood design. For new foundations, foundations raised or extended upward, and replacement foundations, the foundations shall be in compliance with the requirements for new construction for flood design.
For buildings and structures in flood hazard areas established in California Building Code, Section 1612 A .3, any additions that do not constitute substantial improvement of the existing structure , as defined in Chapter 2, are not required to comply with the flood design requirements for new construction, provided that both of the following apply:
- The addition shall not create or extend a nonconformity of the existing building or structure with the flood-resistant construction requirements.
- The lowest floor of the addition shall be at or above the lower of the lowest floor of the existing building or structure or the lowest floor elevation required in Section 1612 A of the California Building Code .
502 A .3 Existing structural elements carrying gravity load. Any existing gravity load-carrying structural element for which an addition and its related alterations cause an increase in design dead, live or snow load, including snow drift effects, of more than 5 percent shall be replaced or altered as needed to carry the gravity loads required by the California Building Code for new structures.
CEBC § 506.2 High relevance — show source text
506.2 Certificate of occupancy. A certificate of occupancy shall be issued where it has been determined that the requirements for the new occupancy classification have been met.
506.3 Stairways. An existing stairway shall not be required to comply with the requirements of Section 1011 of the California Build- ing Code where the existing space and construction does not allow a reduction in pitch or slope.
506.4 Existing emergency escape and rescue openings. Where a change of occupancy would require an emergency escape and rescue opening in accordance with Section 1031.1 of the California Building Code, operable windows serving as the emergency escape and rescue opening shall comply with the following:
- An existing operable window shall provide a minimum net clear opening of 4 square feet (0.38 m [2] ) with a minimum net clear opening height of 22 inches (559 mm) and a minimum net clear opening width of 20 inches (508 mm).
- A replacement window where such window complies with both of the following: 2.1. The replacement window meets the size requirements in Item 1. 2.2. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
[BS] 506.5 Structural. Any building undergoing a change of occupancy shall satisfy the requirements of this section.
Exception: [BSC] For state-owned buildings, including those owned by the University of California and the California State University and the Judicial Council, the performance level requirements of Section 506.5 are replaced with the performance level requirements of Section 317.5.
[BS] 506.5.1 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 need not comply with this section.
[BS] 506.5.2 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.
Exception: Where the area of the new occupancy is less than 10 percent of the building area, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
[BS] 506.5.3 Seismic loads (seismic force-resisting system). Where a change of occupancy results in a building being assigned to a higher risk category, or where the change is from a Group S or Group U occupancy to any occupancy other than Group S or
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CEBC § 422.3 High relevance — show source text
503 A .16 Reserved.
503 A .17 Ambulatory care facilities. Where a work area exceeds 50 percent of the building area and the work area includes an existing ambulatory care facility, the following shall be provided:
- A smoke compartment in accordance with Section 422.3 of the California Building Code where the alteration results in an ambulatory care facility greater than 10,000 square feet on one story.
- Separation from adjacent spaces in accordance with Section 422.2 of the California Building Code, where any such facility has the potential for four or more care recipients are to be incapable of self-preservation at any time.
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503 A .18 Reserved.
503 A .19 Reserved.
503 A .20 Two-way communications systems. Where the work area for alterations exceeds 50 percent of the building area and the building has elevator service, a two-way communication systems shall be provided where required by Section 1009.8 of the Califor- nia Building Code.
SECTION 504 A
RESERVED
SECTION 505 A
RESERVED
SECTION 506 A —CHANGE OF OCCUPANCY
506 A .1 Compliance. A change of occupancy shall not be made in any building unless that building is made to comply with the requirements of the California Building Code for the use or occupancy. Changes of occupancy in a building or portion thereof shall be such that the existing building is not less complying with the provisions of this code than the existing building or structure was prior to the change. Subject to the approval of the building official, changes of occupancy shall be permitted without complying with all of the requirements of this code for the new occupancy, provided that the new occupancy is less hazardous, based on life and fire risk, than the existing occupancy.
Exception: The building need not be made to comply with Chapter 16 A of the California Building Code unless required by Section 506 A .5.
506 A .1.1 Change in function . A change in function shall require compliance with all the functional requirements for new construc- tion in the California Building Code, including requirements in California Building Code Section 1224. Compliance shall be only as necessary to meet the specific provisions and is not intended to require the entire building be brought into compliance.
Exception: Minimum room clearances, areas and dimensions may meet the requirements of the 2001 California Building Code for existing rooms re-used for a similar purpose, subject to the approval of OSHPD.
506 A .2 Certificate of occupancy. A certificate of occupancy shall be issued where it has been determined that the requirements for the new occupancy classification have been met.
506 A .3 Stairways. An existing stairway shall not be required to comply with the requirements of Section 1011 of the California Build- ing Code where the existing space and construction does not allow a reduction in pitch or slope.
CEBC § 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:
- A building or portion thereof undergoes a change of occupancy.
- 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.
CEBC § 0.33 High relevance — show source text
Exceptions:
- 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.
- 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.
- 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.
- 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.)
CEBC § 1004.1 High relevance — show source text
SECTION 1004—FIRE PROTECTION
1004.1 General. Fire protection requirements in Section 1011 shall apply where either of the following occur:
- A building or portion thereof undergoes a change of occupancy.
- 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.
2025 CALIFORNIA EXISTING BUILDING CODE 10-3
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
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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.
Exception: Where the area of the new occupancy is less than 10 percent of the building area. The cumulative effect of occupancy changes over time shall be considered.
[BS] 1006.3 Seismic loads. Where a change of occupancy results in a building being assigned to a higher risk category, or where the change is from a Group S or Group U occupancy to any occupancy other than Group S or Group U, the lateral force-resisting system of the building shall comply with Section 304.3.1 for the new risk category. Where a change of occupancy results in a building being assigned to Risk Category IV and Seismic Design Category D or F, nonstructural components serving any portion of the building changed to Risk Category IV shall comply with the requirements of Section 1613 of the California Building Code or shall comply with ASCE 41 using an objective of operational nonstructural performance with the BSE-1N earthquake hazard level.
Exceptions:
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.
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.
Reserved.
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.
CEBC § 2.1 High relevance — show source text
Exceptions:
- Any stairway replacing an existing stairway within a space where the pitch or slope cannot be reduced shall not be required to comply with the maximum riser height and minimum tread depth requirements.
- In Group R-2.1 and I-2 facilities, required guards enclosing the occupiable roof areas shall be permitted to be greater than 48 inches (1219 mm) above the surface of the occupiable roof where the occupants, because of clinical needs, require restraint or containment as part of a function of a psychiatric or cognitive treatment area.
1011.5.3 Egress capacity. Egress capacity shall meet or exceed the occupant load as specified in the California Building Code for the new occupancy.
1011.5.4 Handrails. Existing stairways shall comply with the handrail requirements of Section 804.13.
1011.5.5 Guards. Existing guards shall comply with the requirements in Section 804.12.
1011.5.6 Existing emergency escape and rescue openings. Where a change of occupancy would require an emergency escape and rescue opening in accordance with Section 1031 of the California Building Code, operable windows serving as the emergency escape and rescue opening shall comply with the following:
- An existing operable window shall provide a minimum net clear opening of 4 square feet (0.38 m [2] ) with a minimum net clear opening height of 22 inches (559 mm) and a minimum net clear opening width of 20 inches (508 mm).
- A replacement window where such window complies with both of the following: 2.1. The replacement window meets the size requirements in Item 1. 2.2. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
10-6 2025 CALIFORNIA EXISTING BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
CHANGE OF OCCUPANCY
1011.6 Heights and areas. Hazard categories in regard to height and area shall be in accordance with Table 1011.6.
TABLE 1011.6—HEIGHTS AND AREAS HAZARD CATEGORIES Col2 RELATIVE HAZARD OCCUPANCY CLASSIFICATIONS 1 (Highest Hazard) H 2 A-1; A-2; A-3; A-4; I; R-1; R-2; R-4, Condition 2 3 E; F-1; S-1; M 4 (Lowest Hazard) B; F-2; S-2; A-5; R-3; R-4, Condition 1; U 1011.6.1 Height and area for change to a higher-hazard category. Where a change of occupancy classification is made to a higher-hazard category as shown in Table 1011.6, heights and areas of buildings and structures shall comply with the requirements of Chapter 5 of the California Building Code for the new occupancy classification.
Exceptions:
- For high-rise buildings constructed in compliance with a previously issued permit, the type of construction reduction specified in Section 403.2.1 of the California Building Code is permitted. This shall include the reduction for columns.
Frequently asked questions
If only a small portion of a floor changes use, do I always need to change structural members?
Not always. If the area of the new occupancy is less than 10 percent of the building area, the snow/wind checks of § 1006.2 are not required; and for live loads, an existing element need not be altered when its demand-capacity ratio increases by no more than 5 percent per § 1006.1. Consider cumulative past changes.
Where do I find the actual live-load psf values I must use?
The CEBC directs you to use the California Building Code live-load provisions in § 1607; § 1006.1 requires CBC § 1607 be used for areas of new occupancy.
Does a change in risk category affect only snow and wind loads?
No. § 1006.2 specifically calls out snow and wind (CBC §§ 1608, 1609), but a risk-category increase can also trigger other upgrades (including seismic provisions per CEBC § 1006.3 and other CEBC sections). Review all related CEBC triggers when a change raises the building’s risk category.
What does “cumulative effect” mean in the exemptions?
It means you cannot repeatedly apply the “less than 10 percent” or “5 percent” exceptions in a way that, over multiple separate projects, leads to an effective large change without triggering the required upgrades. The CEBC requires accounting for prior changes when evaluating exemptions.
If my element’s demand-capacity ratio increases by 6 percent, what happens?
An increase greater than 5 percent exceeds the tolerance in § 1006.1; the element must be evaluated and upgraded to meet the CBC live‑load requirements (CBC § 1607) as required by the CEBC.
More in California Existing Building Code
- Administration and Definitions (Scope, enforcement, code official duties, definitions)
- Provisions for All Compliance Methods (general requirements that apply to all compliance options; Chapter 3 / 3A)
- Seismic retrofit and evaluation (Appendix A and seismic provisions/sections for evaluation and retrofit)
- Referenced Standards and Appendices (Chapter 16 and Appendices A–E, Resource A)
- Repairs (Chapter 4 — repair-specific rules for materials, means of egress, structural, MEP, etc.)
- Alterations — Level 1, Level 2, Level 3 (technical requirements for each alteration level; Chapters 7–9)
- Change of Occupancy and Additions (requirements for occupancy changes and additions; Chapters 10–11)
- Compliance Methods — Prescriptive, Work Area, Performance (Chapters 5, 6–11, 13)
- Relocated Buildings (requirements for buildings moved or relocated; Chapter 14)
- Construction Safeguards (site safety, means of egress and life-safety during construction; Chapter 15)
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