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Chapter 5 — GENERAL BUILDING HEIGHTS AND AREAS

Section 505

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.

505.1 General.

Mezzanines shall comply with Section 505.2. Equipment platforms shall comply with Section 505.3.

505.2 Mezzanines.

A mezzanine or mezzanines in compliance with Section 505.2 shall be considered a portion of the story below. Such mezzanines shall not contribute to either the building area or number of stories as regulated by Section 503.1. The area of the mezzanine shall be included in determining the fire area. The clear height above and below the mezzanine floor construction shall be not less than 7 feet (2134 mm).

505.2.1 Area limitation. The aggregate area of a mezzanine or mezzanines within a room shall be not greater than one-third of the floor area of that room or space in which they are located. The enclosed portion of a room shall not be included in a determination of the floor area of the room in which the mezzanine is located. In determining the allowable mezzanine area, the area of the mezzanine shall not be included in the floor area of the room.

Exceptions:

  1. The aggregate area of mezzanines in buildings and structures of Type I or II construction for special industrial occupancies in accordance with Section 503.1.1 shall be not greater than twothirds of the floor area of the room.

  2. The aggregate area of mezzanines in buildings and structures of Type I or II construction shall be not greater than one-half of the floor area of the room in buildings and structures equipped throughout with an approved automatic sprinkler

system in accordance with Section 903.3.1.1 and an approved emergency voice/alarm communication system in accordance with Section 907.5.2.2.

  1. The aggregate area of a mezzanine within a dwelling unit that is located in a building equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 shall not be greater than one-half of the floor area of the room, provided that:

3.1. Except for enclosed closets and bathrooms, the mezzanine shall be open to the room in which such mezzanine is located;

3.2. The opening to the room shall be unobstructed except for walls not more than 42 inches (1067 mm) in height, columns and posts; and

3.3. Exceptions to Section 505.2.3 shall not be permitted.

505.2.1.1 Aggregate area of mezzanines and equip- ment platforms. Where a room contains both a mezzanine and an equipment platform, the aggregate area of the two raised floor levels shall be not greater than twothirds of the floor area of that room or space in which they are located. The area of the mezzanine shall not exceed the area determined in accordance with Section 505.2.1.

505.2.2 Means of egress. The means of egress for mezzanines shall comply with the applicable provisions of Chapter 10.

505.2.3 Openness. A mezzanine shall be open and unobstructed to the room in which such mezzanine is located except for walls not more than 42 inches (1067 mm) in height, columns and posts.

Exceptions:

  1. Mezzanines or portions thereof are not required to be open to the room in which the mezzanines are located, provided that the occupant load of the aggregate area of the enclosed space is not greater than 10.

  2. A mezzanine having two or more exits or access to exits is not required to be open to the room in which the mezzanine is located.

  3. Mezzanines or portions thereof are not required to be open to the room in which the mezzanines are located, provided that the aggregate floor area of the enclosed space is not greater than 10 percent of the mezzanine area.

  4. In industrial facilities, mezzanines used for control equipment are permitted to be glazed on all sides.

  5. In occupancies other than Groups H and I, which are no more than two stories above grade plane and equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, a mezzanine having two or more exits or access to exits shall not be required to be open to the room in which the mezzanine is located.

182 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 504.4 ALLOWABLE NUMBER OF STORIES ABOVE GRADE PLANEa, b, n
OCCUPANCY
CLASSIFICATION		 TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION
OCCUPANCY
CLASSIFICATION		 SEE FOOTNOTES TYPE I TYPE I TYPE II TYPE II TYPE III TYPE III TYPE IV TYPE V TYPE V
OCCUPANCY
CLASSIFICATION		 SEE FOOTNOTES A B A B A B HT A B
A-1 NS UL 5 3 2 3 2 3 2 1
A-1 S_ (without area increase)_ UL 6 4 3 4 3 4 3 2
A-1 S (with area increase) UL 5 3 2 3 2 3 2 1
A-2 NS UL 11 3 2 3 2 3 2 1
A-2 S_ (without area increase)_ UL 12 4 3 4 3 4 3 2
A-2 S (with area increase) UL 11 3 2 3 2 3 2 1
A-3 NS UL 11 3 2 3 2 3 2 1
A-3 S_ (without area increase)_ UL 12 4 3 4 3 4 3 2
A-3 S (with area increase) UL 11 3 2 3 2 3 2 1
A-4 NS UL 11 3 2 3 2 3 2 1
A-4 S_ (without area increase)_ UL 12 4 3 4 3 4 3 2
A-4 S (with area increase) UL 11 3 2 3 2 3 2 1
A-5 NS UL UL UL UL UL UL UL UL UL
A-5 S UL UL UL UL UL UL UL UL UL
B NS UL 11 5 3 5 3 5 3 2
B S UL 12 6 4 6 4 6 4 3
E NS UL 5 3 2 3 2 3 1 1
E S_ (without area increase)_ UL 6 4 3 4 3 4 2 2
E S (with area increase) UL 5 3 2 3 2 3 1 1
F-1 NS UL 11 4 2 3 2 4 2 1
F-1 S UL 12 5 3 4 3 5 3 2
F-2 NS UL 11 5 3 4 3 5 3 2
F-2 S UL 12 6 4 5 4 6 4 3
H-1 NSc, d 1 1 1 1 1 1 1 1 NP
H-1 S S S S S S S S S S
H-2 NSc, d 20 3 2 1 2 1 2 1 1
H-2 S S S S S S S S S S
H-3 NSc, d 20 6 4 2 4 2 4 2 1
H-3 S S S S S S S S S S
H-4 NSc, d 20 7 5 3 5 3 5 3 2
H-4 S_ (without area increase)_ 20 8 6 4 6 4 6 4 3
H-4 S (with area increase) 20 7 5 3 5 3 5 3 2
H-5 NSc, d 4 4 3 3 3 3 3 3 2
H-5 S S S S S S S S S S
I-2,I-2.1j, i NSd, f UL 4 2 1 1 NP 1 1 NP
I-2,I-2.1j, i S_ (without area increase)_ UL 5 3 3 3 3 3 3 3
I-2,I-2.1j, i S (with area increase) UL 4 2 2 2 2 2 2 2
I-3 NSd, e NP NP NP NP NP NP NP NP NP
I-3 S_ (without area increase)_ UL 3 NP NP NP NP NP NP NP
I-3 S (with area increase) UL 2 NP NP NP NP NP NP NP
I-4 NSd, g UL 5 3 2 3 2 3 1 1
I-4 S_ (without area increase)_ UL 6 4 3 4 3 4 2 2
I-4 S (with area increase) UL 5 3 2 3 2 3 1 1
L NS NP NP NP NP NP NP NP NP NP
L S 20 6 5 3 5 3 5 3 2
M NS UL 11 4 2 4 2 4 3 1
M S UL 12 5 3 5 3 5 4 2

(continued)

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 504.4—continued ALLOWABLE NUMBER OF STORIES ABOVE GRADE PLANEa, b, n
OCCUPANCY
CLASSIFICATION		 TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION TYPE OF CONSTRUCTION
OCCUPANCY
CLASSIFICATION		 SEE FOOTNOTES TYPE I TYPE I TYPE II TYPE II TYPE III TYPE III TYPE IV TYPE V TYPE V
OCCUPANCY
CLASSIFICATION		 SEE FOOTNOTES A B A B A B HT A B
R-1h NSd UL 11 4 4 4 4 4 3 2
R-1h S13R 4 4 4 4 4 4 4 3 2
R-1h S_ (without area increase)_ UL 12 5 5 5 5 5 4 3
R-1h S (with area increase) UL 11 4 4 4 4 4 3 2
R-2h NSd UL 11 4 4 4 4 4 3 2
R-2h S13R 4 4 4 4 4 4 4 4 3
R-2h S_ (without area increase)_ UL 12 5 5 5 5 5 4 3
R-2h S (with area increase) UL 11 4 4 4 4 4 4o 2
R-2.2h S (without area increase) UL 12 _5 _ 5 5 5 5 _4 _ 3
R-2.2h S (with area increase) UL 11 4 4 4 4 4 4o 2
R-2.1h NSd UL 6l 3k NP 3k NP NP 3k NP
R-2.1h S13R UL 4l 3k NP 3k NP NP 3k NP
R-2.1h S UL 6l 3k NP 3k NP NP 3k NP
R-3_, R-3.1_h NSd UL 11 4 4 4 4 4 3 3
R-3_, R-3.1_h S13D 4 4 4 4 4 4 4 3 3
R-3_, R-3.1_h S13R 4 4 4 4 4 4 4 4 4
R-3_, R-3.1_h S UL 12 5 5 5 5 5 4 4
R-4h NSd UL 11_l_ 4_k_ 4_m_ 4_k_ 4_m_ 4_m_ 3_k_ 2_m_
R-4h S13D 4 4_l_ 4_l_ 4_l_ 4_l_ 4_l_ 4_l_ 3_k_ 2_m_
R-4h S13R 4 4_l_ 4_l_ 4_l_ 4_l_ 4_l_ 4_l_ 4 3
R-4h S UL 11l 5 5 5 5 5 4 3
S-1 NS UL 11 4 2 3 2 4 3 1
S-1 S UL 12 5 3 4 3 5 4 2
S-2_i_ NS UL 11 5 3 4 3 4 4 2
S-2_i_ S UL 12 6 4 5 4 5 5 3
U NS UL 5 4 2 3 2 4 2 1
U S UL 6 5 3 4 3 5 3 2

UL = Unlimited; NP = Not Permitted; NS = Buildings not equipped throughout with an automatic sprinkler system; S = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1; S13R = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.2; S13D = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.3. a. See Chapters 4 and 5 for specific exceptions to the allowable height in this chapter. b. See Section 903.2 for the minimum thresholds for protection by an automatic sprinkler system for specific occupancies. c. New Group H occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.5. d. The NS value is only for use in evaluation of existing building height in accordance with the California Existing Building Code . e. New Group I-1 and I-3 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6. For new Group I-1

occupancies, Condition 1, see Exception 1 of Section 903.2.6. f. New and existing Group I-2 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6 and 1103.5 of the

California Fire Code . g. For new Group I-4 occupancies, see Exceptions 2 and 3 of Section 903.2.6. h. New Group R occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.8. i. See Sections 407.1.1 and 408.1.2 for specific exceptions to construction type, allowable building areas and allowable heights. j. Restraint shall not be permitted in any building except in Group I-3 occupancies constructed for such use (see Section 408.1.2). k. Nonambulatory persons shall be limited to the first 2 stories. l. Nonambulatory persons shall be limited to the first 5 stories. m. Nonambulatory elderly clients are not permitted in buildings of these types of construction. See Sections 435.3.3 and 435.3.4. n. In other than Group A, E, H, I, L, and R occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire

Marshal, the S increases for height and stories in Tables 504.3 and 504.4 are permitted in addition to the S area increase in accordance with Table 506.2. o. For Group R-2 buildings of Type VA construction equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1,

S area increase is permitted in addition to the height and story increase provided the height shall not exceed 60 feet and 4 stories.

184 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

505.3 Equipment platforms.

Equipment platforms in buildings shall not be considered as a portion of the floor below. Such equipment platforms shall not contribute to either the building area or the number of stories as regulated by Section 503.1. The area of the equipment platform shall not be included in determining the fire area in accordance with Section 903. Equipment platforms shall not be a part of any mezzanine and such platforms and the walkways, stairways, alternating tread devices and ladders providing access to an equipment platform shall not serve as a part of the means of egress from the building.

505.3.1 Area limitation. The aggregate area of all equipment platforms within a room shall be not greater than two-thirds of the area of the room in which they are located. Where an equipment platform is located in the same room as a mezzanine, the area of the mezzanine shall be determined by Section 505.2.1 and the combined aggregate area of the equipment platforms and mezzanines shall be not greater than two-thirds of the room in which they are located. The area of the mezzanine shall not exceed the area determined in accordance with Section 505.2.1.

505.3.2 Automatic sprinkler system. Where located in a building that is required to be protected by an automatic sprinkler system, equipment platforms shall be fully protected by sprinklers above and below the platform, where required by the standards referenced in Section 903.3.

505.3.3 Guards. Equipment platforms shall have guards where required by Section 1015.2.

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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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