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Chapter 4 — RESIDENTIAL MANDATORY MEASURES

Section 4.505

California Green Building Standards Code (Title 24, Part 11) · 2022 edition · updated 2026-09-12 · California

INTERIOR MOISTURE CONTROL 4.505.1 General. Buildings shall meet or exceed the provisions of the California Building Standards Code.

4.505.2 Concrete slab foundations. Concrete slab foundations required to have a vapor retarder by the California Building Code, Chapter 19 or concrete slab-on-ground floors required to have a vapor retarder by the California Residen- tial Code, Chapter 5, shall also comply with this section.

4.505.2.1 Capillary break. A capillary break shall be installed in compliance with at least one of the following:

  1. A 4-inch-thick (101.6 mm) base of 1 /2 inch (12.7 mm) or larger clean aggregate shall be provided with a vapor retarder in direct contact with concrete and a concrete mix design, which will address bleeding, shrinkage and curling, shall be used. For additional information, see American Concrete Institute, ACI 302.2R-06.

  2. Other equivalent methods approved by the enforcing agency.

  3. A slab design specified by a licensed design professional.

4.505.3 Moisture content of building materials. Building materials with visible signs of water damage shall not be installed. Wall and floor framing shall not be enclosed when the framing members exceed 19 percent moisture content. Moisture content shall be verified in compliance with the following:

  1. Moisture content shall be determined with either a probe-type or contact-type moisture meter. Equivalent moisture verification methods may be approved by the enforcing agency and shall satisfy requirements found in Section 101.8 of this code.

Copyright © 2022 by, or licensed to, International Code Council, Inc. (ALL RIGHTS RESERVED); licensed to California Building Standards Commission pursuant to License Agreement. No further reproductions is authorized. 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.

RESIDENTIAL MANDATORY MEASURES

  1. Moisture readings shall be taken at a point 2 feet (610 mm) to 4 feet (1219 mm) from the grade stamped end of each piece to be verified.

  2. At least three random moisture readings shall be performed on wall and floor framing with documentation acceptable to the enforcing agency provided at the time of approval to enclose the wall and floor framing. Insulation products which are visibly wet or have a high moisture content shall be replaced or allowed to dry prior to enclosure in wall or floor cavities. Wet-applied insulation products shall follow the manufacturers’ drying recommendations prior to enclosure.

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▸Contents — California Green Building Standards Code (Title 24, Part 11)
California Green Building Standards Code (Title 24, Part 11)
  1. Chapter 1 — ADMINISTRATION
  2. Chapter 2 — DEFINITIONS
  3. Chapter 3 — GREEN BUILDING
  4. ▸Chapter 4 — RESIDENTIAL MANDATORY MEASURES
    Overview
    1. Section 4.101
    2. Section 4.102
    3. Section 4.103
    4. Section 4.104
    5. Section 4.106
    6. Section 4.105
    7. Section 4.201
    8. Section 4.301
    9. Section 4.302
    10. Section 4.303
    11. Section 4.304
    12. Section 4.305
    13. Section 4.401
    14. Section 4.402
    15. Section 4.403
    16. Section 4.404
    17. Section 4.405
    18. Section 4.406
    19. Section 4.407
    20. Section 4.408
    21. Section 4.409
    22. Section 4.410
    23. Section 4.501
    24. Section 4.502
    25. Section 4.503
    26. Section 4.504
    27. Section 4.505
    28. Section 4.506
    29. Section 4.508
    30. Section 4.507
  5. Chapter 5 — NONRESIDENTIAL MANDATORY MEASURES
  6. Chapter 6 — REFERENCED ORGANIZATIONS AND STANDARDS
  7. Chapter 7 — INSTALLER AND SPECIAL INSPECTOR QUALIFICATIONS
  8. Chapter 8 — COMPLIANCE FORMS, WORKSHEETS AND REFERENCE MATERIAL
  9. Appendix A4
  10. Appendix A5

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