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Chapter 5 — GENERAL BUILDING HEIGHTS AND AREAS

Section 508

California Building Code (Title 24, Part 2) · 2019 edition · updated 2026-09-12 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

508.1 General.

Each portion of a building shall be individually classified in accordance with Section 302.1. Where a building contains more than one occupancy group, the building or portion thereof shall comply with the applicable provisions of Section 508.2, 508.3 or 508.4, or a combination of these sections.

Exceptions:

  1. Occupancies separated in accordance with Section

  3. Where required by Table 415.6.2, areas of Group H1, H-2 and H-3 occupancies shall be located in a detached building or structure.

Copyright © 2019 ICC. ALL RIGHTS RESERVED. Accessed by Kevin Day (kevin.day@dgs.ca.gov), (California Building Standards Commission) Order Number #100735044 on Jul 24, 2019 03:54 PM (PDT) pursuant to License Agreement with ICC. No further reproduction or distribution authorized. Single user only, copying and networking prohibited. ANY UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS A VIOLATION OF THE FEDERAL COPYRIGHT ACT AND THE LICENSE AGREEMENT, AND SUBJECT TO CIVIL AND CRIMINAL PENALTIES THEREUNDER.

100735044

GENERAL BUILDING HEIGHTS AND AREAS

  1. Uses within live/work units, complying with Section 419, are not considered separate occupancies.

508.2 Accessory occupancies.

Accessory occupancies are those occupancies that are ancillary to the main occupancy of the building or portion thereof. Accessory occupancies shall comply with the provisions of Sections 508.2.1 through 508.2.4.

508.2.1 Occupancy classification. Accessory occupancies shall be individually classified in accordance with Section 302.1. The requirements of this code shall apply to each portion of the building based on the occupancy classification of that space.

508.2.2 Allowable building height. The allowable height and number of stories of the building containing accessory occupancies shall be in accordance with Section 504 for the main occupancy of the building.

508.2.3 Allowable building area. The allowable area of the building shall be based on the applicable provisions of Section 506 for the main occupancy of the building. Aggregate accessory occupancies shall not occupy more than 10 percent of the floor area of the story in which they are located and shall not exceed the tabular values for nonsprinklered buildings in Table 506.2 for each such accessory occupancy.

508.2.4 Separation of occupancies. No separation is required between accessory occupancies and the main occupancy.

Exceptions:

  1. Group H-2, H-3, H-4 and H-5 and L occupancies shall be separated from all other occupancies in accordance with Section 508.4.

  2. Group R-1, R-2, R-2.1, R-2.2 and R-3 dwelling units and sleeping units shall be separated from other dwelling or sleeping units and from accessory occupancies contiguous to them in accordance with the requirements of Section 420.

3. Group I-2 and I-2.1 shall be separated from all other occupancies in accordance with Section 508.4. No separation is required between Group B, E, R-2 sleeping units and S-2 occupancies accessory to Group I-2, I-2.1.

4. Group I-3 and vehicle sally-ports shall be sepa- rated from all other occupancies in accordance with Section 508.4. No separation is required between Group B, E, R-2 sleeping units and S-2 occupancies accessory to Group I-3 of Type I Construction.

508.3 Nonseparated occupancies.

Buildings or portions of buildings that comply with the provisions of this section shall be considered as nonseparated occupancies.

508.3.1 Occupancy classification. Nonseparated occupancies shall be individually classified in accordance with Section 302.1. The requirements of this code shall apply to each portion of the building based on the occupancy classification of that space. In addition, the most restrictive provisions of Chapter 9 that apply to the nonseparated

occupancies shall apply to the total nonseparated occupancy area.

508.3.1.1 High-rise buildings. Where nonseparated occupancies occur in a high-rise building, the most restrictive requirements of Section 403 that apply to the nonseparated occupancies shall apply throughout the high-rise building.

508.3.1.2 Group I-2, Condition 2 occupancies. Where one of the nonseparated occupancies is Group I-2, Condition 2, the most restrictive requirements of Sections 407, 509 and 712 shall apply throughout the fire area containing the Group I-2 occupancy. The most restrictive requirements of Chapter 10 shall apply to the path of egress from the Group I-2, Condition 2 occupancy up to and including the exit discharge.

508.3.2 Allowable building area, height and number of stories. The allowable building area, height and number of stories of the building or portion thereof shall be based on the most restrictive allowances for the occupancy groups under consideration for the type of construction of the building in accordance with Section 503.1.

508.3.3 Separation. No separation is required between nonseparated occupancies.

Exceptions:

  1. Group H-2, H-3, H-4 and H-5 , I-2, I-2.1 and L occupancies shall be separated from all other occupancies in accordance with Section 508.4.

  2. Group R-1, R-2, R-2.1, R-2.2 and R-3 dwelling units and sleeping units shall be separated from other dwelling or sleeping units and from other occupancies contiguous to them in accordance with the requirements of Section 420.

3. Separation is required between Group I-3 and vehicle sally ports.

4. Where Group I-3 is not the main occupancy and the area is greater than 10 percent of the floor area, it shall be separated per Table 508.4.

508.4 Separated occupancies.

Buildings or portions of buildings that comply with the provisions of this section shall be considered as separated occupancies.

508.4.1 Occupancy classification. Separated occupancies shall be individually classified in accordance with Section 302.1. Each separated space shall comply with this code based on the occupancy classification of that portion of the building. The most restrictive provisions of Chapter 9 that apply to the separate occupancies shall apply to the total nonfire-barrier-separated occupancy areas. Occupancy separations that serve to define fire area limits established in Chapter 9 for requiring a fire protection system shall also comply with Section 901.7.

508.4.2 Allowable building area. In each story, the building area shall be such that the sum of the ratios of the actual building area of each separated occupancy divided by the allowable building area of each separated occupancy shall not exceed 1.

192 2019 CALIFORNIA BUILDING CODE

Copyright © 2019 ICC. ALL RIGHTS RESERVED. Accessed by Kevin Day (kevin.day@dgs.ca.gov), (California Building Standards Commission) Order Number #100735044 on Jul 24, 2019 03:54 PM (PDT) pursuant to License Agreement with ICC. No further reproduction or distribution authorized. Single user only, copying and networking prohibited. ANY UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS A VIOLATION OF THE FEDERAL COPYRIGHT ACT AND THE LICENSE AGREEMENT, AND SUBJECT TO CIVIL AND CRIMINAL PENALTIES THEREUNDER.

100735044

GENERAL BUILDING HEIGHTS AND AREAS

TABLE 508.4 REQUIRED SEPARATION OF OCCUPANCIES (HOURS) h

OCCUPANCY A, E I-4, R-2.1 I-2, I-2.1 I-3 R-1, R-2,
R-3, R-3.1,
R-4		 F-2,
S-2b, U		 Bf, F-1g, h,
M, S-1		 L H-1 H-2 H-3, H-4 H-5
OCCUPANCY S NS S NS S NS S NS S NS S NS S NS S NS S NS S NS S NS S NS
A, E N N 2 2 2 NP 2 NP 1 2 N 1 1 2 2 NP NP NP 3 4 2 3 2 NP
I-4,_ R-2.1_ — — 1e NP 2 NP 2 NP 1 NP 1 2 1 2 2 NP NP NP 4 NP 2 NP 2 NP
I-2_, I-2.1_ — — — — N NP 2 NP 2 NP 2 NP 2 NP 2 NP NP NP 4 NP 2 NP 2 NP
I-3 — — — — — — N NP 2 NP 2 2 2 2 2 _NP _ NP NP 4 NP
R_-1, R-2, R-3,_
R-3.1, R-4		 — — — — — — — — N N 1c 2c 1 2 4 NP NP NP 3 NP 2 NP 2 NP
F-2, S-2b, U — — — — — — — — — — N N 1 2 1 NP NP NP 3 4 2 3 2 NP
B, F-1, M, S-1 — — — — — — — — — — — — N N 1 NP NP NP 2 3 1 2 1 NP
L — — — — — — — — — — 1 _NP _ NP NP 2 NP
H-1 — — — — — — — — — — — — — — — — N NP NP NP NP NP NP NP
H-2 — — — — — — — — — — — — — — — — — — N NP 1 NP 1 NP
H-3, H-4 — — — — — — — — — — — — — — — — 1d NP 1 NP 1d NP 1 NP
H-5 — — — — — — — — — — — — — — — — — — N NP — — N NP

S = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1. NS = Buildings not equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1. N = No separation requirement. NP = Not Permitted. a. See Section 420. b. The required separation from areas used only for private or pleasure vehicles shall be reduced by 1 hour but not to less than 1 hour. c. See Section 406.3.2. d. Separation is not required between occupancies of the same classification. e. See Section 422.2 for ambulatory care facilities. f. Occupancy separations that serve to define fire area limits established in Chapter 9 for requiring fire protection systems shall also comply with Section

707.3.10 and Table 707.3.10 in accordance with Section 901.7. g. [SFM] Group I and F1 occupancies and Group R-2.1 and F-1 occupancies shall have a 3 hour separation. h. [SFM] Commercial kitchens not associated with cafeterias and similar dining facilities in Group I-2 and Group R-2.1 shall have a 2-hour separation and

shall be protected by an automatic sprinkler system.

508.4.3 Allowable building height and number of sto- ries. Each separated occupancy shall comply with the building height limitations and story limitations based on the type of construction of the building in accordance with Section 503.1.

Exception: Special provisions of Section 510 shall permit occupancies at building heights and number of stories other than provided in Section 503.1.

508.4.4 Separation. Individual occupancies shall be separated from adjacent occupancies in accordance with Table 508.4.

508.4.4.1 Construction. Required separations shall be fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both, so as to completely separate adjacent occupancies.

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▸Contents — California Building Code (Title 24, Part 2)
California Building Code (Title 24, Part 2)
  1. Chapter 2 — DEFINITIONS AND ABBREVIATIONS
  2. Appendix G — FLOOD-RESISTANT
  3. Appendix L — EARTHQUAKE RECORDING
  4. Appendix M — TSUNAMI-GENERATED
  5. Chapter 1 — SCOPE AND ADMINISTRATION
  6. Chapter 3 — OCCUPANCY CLASSIFICATION AND USE
  7. Chapter 4 — SPECIAL DETAILED REQUIREMENTS BASED
  8. ▸Chapter 5 — GENERAL BUILDING HEIGHTS AND AREAS
    Overview
    1. Section 501
    2. Section 502
    3. Section 503
    4. Section 504
    5. Section 505
    6. Section 506
    7. Section 507
    8. Section 508
    9. Section 509
    10. Section 510
  9. Chapter 6 — TYPES OF CONSTRUCTION
  10. Chapter 7 — FIRE AND SMOKE PROTECTION FEATURES
  11. Chapter 7A — MATERIALS AND CONSTRUCTION
  12. Chapter 8 — INTERIOR FINISHES
  13. Chapter 9 — FIRE PROTECTION AND LIFE SAFETY SYSTEMS
  14. Chapter 10 — MEANS OF EGRESS
  15. Chapter 11A — HOUSING ACCESSIBILITY
  16. Chapter 11B — ACCESSIBILITY TO PUBLIC BUILDINGS, PUBLIC ACCOMM…
  17. Chapter 12 — INTERIOR ENVIRONMENT
  18. Chapter 14 — EXTERIOR WALLS
  19. Chapter 15 — ROOF ASSEMBLIES AND ROOFTOP STRUCTURES
  20. Chapter 16 — STRUCTURAL DESIGN
  21. Chapter 16A — STRUCTURAL DESIGN
  22. Chapter 17 — SPECIAL INSPECTIONS AND TESTS
  23. Chapter 18 — SOILS AND FOUNDATIONS
  24. Chapter 19 — CONCRETE
  25. Chapter 20 — ALUMINUM
  26. Chapter 21 — MASONRY
  27. Chapter 22 — STEEL
  28. Chapter 23 — WOOD
  29. Chapter 24 — GLASS AND GLAZING
  30. Chapter 25 — GYPSUM BOARD, GYPSUM PANEL PRODUCTS AND PLASTER
  31. Chapter 26 — PLASTIC
  32. Chapter 27 — ELECTRICAL
  33. Chapter 28 — MECHANICAL SYSTEMS
  34. Chapter 30 — ELEVATORS AND CONVEYING SYSTEMS
  35. Chapter 31 — SPECIAL CONSTRUCTION
  36. Chapter 31B — PUBLIC POOLS
  37. Chapter 31C — RADIATION
  38. Chapter 31D — FOOD ESTABLISHMENTS
  39. Chapter 31F — MARINE OIL TERMINALS
  40. Chapter 32 — ENCROACHMENTS INTO THE PUBLIC RIGHT-OF-WAY
  41. Chapter 33 — SAFEGUARDS DURING CONSTRUCTION
  42. Chapter 35 — REFERENCED STANDARDS
  43. Appendix A — EMPLOYEE QUALIFICATIONS
  44. Appendix B — BOARD OF APPEALS
  45. Appendix C — GROUP U – AGRICULTURAL BUILDINGS
  46. Appendix D — FIRE DISTRICTS
  47. Appendix F — RODENTPROOFING
  48. Appendix H — SIGNS
  49. Appendix I — PATIO COVERS
  50. Appendix J — GRADING
  51. Appendix K — GROUP R-3 AND GROUP R-3.1 OCCUPANCIES
  52. Appendix N — REPLICABLE BUILDINGS
  53. Appendix O — EMERGENCY HOUSING

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