Skip to content
ChatProjectCodes

Chapter 25 — GYPSUM BOARD, GYPSUM PANEL PRODUCTS AND PLASTER

Section 2504

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.

2504.1 Scope.

The following requirements shall be met where construction involves gypsum board, gypsum panel products or lath and plaster in vertical and horizontal assemblies.

2504.1.1 Wood framing. Wood supports for lath, gypsum board or gypsum panel products, as well as wood stripping or furring, shall be not less than 2 inches (51 mm) nominal thickness in the least dimension.

Exception: The minimum nominal dimension of wood furring strips installed over solid backing shall be not less than 1 inch by 2 inches (25 mm by 51 mm).

2504.1.2 Studless partitions. The minimum thickness of vertically erected studless solid plaster partitions of 3 /8inch (9.5 mm) and 3 /4-inch (19.1 mm) rib metal lath, 1 /2inch-thick (12.7 mm) gypsum lath, gypsum board or gypsum panel product shall be 2 inches (51 mm).

2504.2 Additional requirements. [DSA-SS, DSA-SS/CC and

OSHPD 1, 1R, 2, 4 & 5] In addition to the requirements of this section, the horizontal and vertical assemblies of plaster, gypsum board or gypsum panel products shall be designed to resist the loads specified in this code.

2504.2.1 Wood furring strips. Wood furring strips for ceilings fastened to floor or ceiling joist shall be nailed at each bearing with two common wire nails, one of which shall be a slant nail and the other a face nail, or by one nail having spirally grooved or annular grooved shanks approved by the enforcement agency for this purpose. All stripping nails shall penetrate not less than 1 3 /4 inches (44.5 mm) into the member receiving the point. Holes in stripping at joints shall be subdrilled to prevent splitting.

Where common wire nails are used to support horizontal wood stripping for plaster ceilings, such stripping shall be wire tied to the joists 4 feet (1219 mm) on center with two strands of No. 18 W&M gage galvanized annealed wire to an 8d common wire nail driven into each side of the joist 2

inches (51 mm) above the bottom of the joist or to each end of a 16d common wire nail driven horizontally through the joist 2 inches (51 mm) above the bottom of the joist, and the ends of the wire secured together with three twists of the wire.

Exception: [OSHPD 2] Single-story Type V skilled nursing or intermediate care facilities utilizing wood- frame or light-steel-frame construction.

Get a plain-English answer with a citation back to this text.

Ask AI about this code
Export this section
▸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
  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
    Overview
    1. Section 2501
    2. Section 2502
    3. Section 2503
    4. Section 2504
    5. Section 2505
    6. Section 2506
    7. Section 2507
    8. Section 2508
    9. Section 2509
    10. Section 2510
    11. Section 2511
    12. Section 2512
    13. Section 2513
    14. Section 2514
  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

GoCodebook provides public access, search, citation, multilingual explanation, and practical interpretation of legally adopted building regulations. It is not a substitute for the official ICC or California code publications.