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Appendix A5

Section A5.105 — DECONSTRUCTION AND REUSE OF EXISTING STRUCTURES

California Green Building Standards Code (Title 24, Part 11) · 2025 edition · updated 2026-09-12 · California

A5.105.1 Scope. Projects with the area limits specified shall comply with Section A5.105.2 to achieve Tier 1 or Tier 2 compliance.

  1. Alteration(s) to existing building(s) where the combined altered floor area is 50,000 square feet or greater shall comply with either Section A5.105.2, Section A5.409.2, or Section A5.409.3.
  2. Addition(s) to existing building(s) where the total floor area combined with the existing building(s) is 50,000 square feet or greater shall comply with either Section A5.105.2, Section A5.409.2, or Section A5.409.3. Exception: Combined addition(s) to existing building(s) of two times the area or more of the existing building(s) is not eligible to meet compliance with Section A5.105.2.
  3. Alteration(s) to existing building(s) where the aggregate floor area is less than 50,000 square feet shall comply with either Section 5.105.2, Section 5.409.2 or Section 5.409.3 for Tier 1 compliance, and either Section A5.105.2.1, Section A5.409.2.1, or A5.409.3 Tier 1 requirements for Tier 2 compliance.
  4. Addition(s) to an existing building where the total floor area combined with the existing building(s) is less than 50,000 square feet shall comply with either Section 5.105.2, Section 5.409.2 or Section 5.409.3 for Tier 1 compliance, and either Section A5.105.2.1, Section A5.409.2.1, or A5.409.3 Tier 1 requirements for Tier 2 compliance. Exception: Combined addition(s) to existing building(s) of two times the area or more of the existing building(s) is not eligible to meet compliance with Section 5.105.2 or Section A5.105.2.

A5.105.2 Reuse of existing building. Projects that include the reuse of an existing building shall meet the minimum requirements of Section A5.105.2.

A5.105.2.1 Tier 1: An alteration or addition to an existing building shall maintain at least 75 percent combined of the existing building’s primary structural elements (foundations; columns, beams, walls, and floors; and lateral elements) and existing building enclosure (roof framing, wall framing and exterior finishes). Window assemblies, insulation, portions of buildings deemed structurally unsound or hazardous, and hazardous materials that are remediated as part of the project shall not be included in the calculation.

A5.105.2.2 Tier 2: An alteration or addition to an existing building shall maintain at least 75 percent combined of the existing building’s primary structural elements (foundations; columns, beams, walls, and floors; and lateral elements) and existing building enclosure (roof framing, wall framing and exterior finishes). In addition, an alteration to an existing building shall maintain 30 percent of existing interior nonstructural elements (interior walls, doors, floor coverings, ceiling systems). Window assemblies, insulation, portions of buildings deemed structurally unsound or hazardous, and hazardous materials that are remediated as part of the project shall not be included in the calculation.

APPENDIX A5-4 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

APPENDIX A5 — NONRESIDENTIAL VOLUNTARY MEASURES

A5.105.2.3 Verification of compliance. Documentation shall be provided in the construction documents to demonstrate compliance with Section A5.105.2.

Note: Sample Worksheet WS-6 in Chapter 8 may be used to assist in documenting compliance with this section.

A5.105.3 Deconstruction (Reserved).

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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
  5. Chapter 4 — RESIDENTIAL MANDATORY MEASURES
  6. Chapter 4 — RESIDENTIAL MANDATORY MEASURES
  7. Chapter 4 — RESIDENTIAL MANDATORY MEASURES
  8. Chapter 4 — RESIDENTIAL MANDATORY MEASURES
  9. Chapter 5 — NONRESIDENTIAL MANDATORY MEASURES
  10. Chapter 5 — NONRESIDENTIAL MANDATORY MEASURES
  11. Chapter 5 — NONRESIDENTIAL MANDATORY MEASURES
  12. Chapter 5 — NONRESIDENTIAL MANDATORY MEASURES
  13. Chapter 5 — NONRESIDENTIAL MANDATORY MEASURES
  14. Chapter 6 — REFERENCED ORGANIZATIONS AND STANDARDS
  15. Chapter 7 — INSTALLER AND SPECIAL INSPECTOR QUALIFICATIONS
  16. Chapter 8 — COMPLIANCE FORMS, WORKSHEETS AND REFERENCE MATERIAL
  17. Appendix A4
  18. ▸Appendix A5
    Overview
    1. Section A5.101 — GENERAL
    2. Section A5.102 — DEFINITIONS
    3. Section A5.103 — SITE SELECTION
    4. Section A5.104 — SITE PRESERVATION
    5. Section A5.105 — DECONSTRUCTION AND REUSE OF EXISTING STRUCTURES
    6. Section A5.106 — SITE DEVELOPMENT
    7. Section A5.107 — BIRD-FRIENDLY BUILDING DESIGN
    8. Section A5.201 — GENERAL
    9. Section A5.202 — DEFINITIONS
    10. Section A5.203 — PERFORMANCE APPROACH
    11. Section A5.204 — MANDATORY REQUIREMENTS FOR ALTERATIONS TO EXI…
    12. Section A5.211 — RESERVED
    13. Section A5.212 — ELEVATORS, ESCALATORS AND OTHER EQUIPMENT
    14. Section A5.213 — ENERGY EFFICIENT FRAMING
    15. Section A5.301 — GENERAL
    16. Section A5.302 — DEFINITIONS
    17. Section A5.303 — INDOOR WATER USE
    18. Section A5.304 — OUTDOOR WATER USE
    19. Section A5.305 — WATER REUSE
    20. Section A5.401 — GENERAL
    21. Section A5.402 — DEFINITIONS
    22. Section A5.403 — FOUNDATION SYSTEMS
    23. Section A5.404 — EFFICIENT FRAMING TECHNIQUES
    24. Section A5.405 — MATERIAL SOURCES
    25. Section A5.406 — ENHANCED DURABILITY AND REDUCED MAINTENANCE
    26. Section A5.408 — CONSTRUCTION WASTE REDUCTION, DISPOSAL AND RE…
    27. Section A5.409 — LIFE CYCLE ASSESSMENT
    28. Section A5.501 — GENERAL
    29. Section A5.502 — DEFINITIONS
    30. Section A5.504 — POLLUTANT CONTROL
    31. Section A5.507 — ENVIRONMENTAL COMFORT
    32. Section A5.508 — OUTDOOR AIR QUALITY
  19. Appendix A6

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