CALGreen · California Green Building Standards Code (CALGreen)

Reuse and deconstruction requirements for existing nonresidential buildings

Q: What exactly counts toward the **45%** preservation calculation?

The code counts preserved primary structural elements (foundations; columns, beams, walls, floors; lateral elements) and existing building enclosure (roof framing, wall framing, exterior finishes). Window assemblies, insulation, structurally unsound/hazardous portions, and remediated hazardous materials are excluded . See § 5.105.2 .

Q: Where do I show proof of compliance?

Provide documentation in the construction documents demonstrating compliance with § 5.105.2 , per § 5.105.2.1 . The code notes Worksheet WS‑3 in Chapter 8 as an example form.

Q: Can I choose a life‑cycle assessment path instead of preserving 45%?

Yes. § 5.105.1 allows projects that meet the thresholds to comply by § 5.105.2 (reuse) or § 5.409.2/5.409.3 (life‑cycle alternatives). Select the path appropriate to the project and document accordingly.

Q: If my addition is massive (≥ 2× existing area), can I still use the reuse path?

No — the exception in § 5.105.1 disallows using § 5.105.2 when the combined addition(s) equal two times the area or more of the existing building.

If your nonresidential alteration or addition is large enough (thresholds in § 5.105.1), California requires you either to preserve at least 45% of the existing building’s primary structure and enclosure (per § 5.105.2) or use a life‑cycle alternative, and to document compliance in the construction documents under § 5.105.2.1.

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Last reviewed: July 6, 2026

What the code requires — plain English

Effective dates and thresholds in § 5.105.1 determine when reuse/deconstruction rules apply: large alterations or additions must either follow reuse requirements in § 5.105.2 or take an approved life‑cycle path (Sections 5.409.2 or 5.409.3). When the reuse path is used, an alteration or addition must preserve at least 45 percent combined of the building’s primary structural elements and existing building enclosure, and the project must show that in the construction documents per § 5.105.2.1.

The single most important rule: if your project meets the size thresholds in § 5.105.1, you must either preserve a minimum portion of the existing structure and enclosure (45%) under § 5.105.2 or use an approved life‑cycle alternative — and you must document compliance in the construction documents per § 5.105.2.1.

Requirements in detail

1) Scope & applicability (when this applies)

The rule in § 5.105.1 applies to:
- Alterations to existing building(s) when the combined altered floor area meets the threshold; and
- Additions when the total floor area (existing + addition) meets the threshold.
Threshold timeline in § 5.105.1:
- Effective July 1, 2024: projects with combined altered/total floor area 100,000 square feet or greater must comply with § 5.105.2, 5.409.2, or 5.409.3.
- Effective January 1, 2026: that same threshold becomes 50,000 square feet.
Special enforcement path for Division of the State Architect (DSA‑SS): DSA requires compliance at 50,000 square feet (no phased threshold).
Exception: combined additions equal to two times the area or more of the existing building are not eligible to meet compliance with § 5.105.2 (i.e., you cannot satisfy the reuse path for very large additions by simply treating them as part of the existing building).

2) Reuse minimums (what must be preserved)

If you use the reuse route, § 5.105.2 requires maintaining at least 45 percent combined of:
- Primary structural elements — foundations; columns, beams, walls, and floors; and lateral elements; and
- Existing building enclosure — roof framing, wall framing and exterior finishes.
Items explicitly excluded from the calculation: window assemblies, insulation, portions of buildings found structurally unsound or hazardous, and hazardous materials remediated as part of the project.

3) Verification / documentation

§ 5.105.2.1 requires documentation in the construction documents demonstrating compliance with § 5.105.2. The code notes that Worksheet WS‑3 in Chapter 8 may be used to document compliance.

Quick reference decision table

Decision dimension	Values / thresholds	How it affects your project	Code Reference
Alteration/addition size threshold (initial)	100,000 sq ft (effective 7/1/2024)	Projects ≥ this size must comply with reuse or life‑cycle alternatives	§ 5.105.1
Alteration/addition size threshold (from 1/1/2026)	50,000 sq ft (effective 1/1/2026)	Lowers the applicability threshold statewide	§ 5.105.1
Alternate DSA‑SS threshold	50,000 sq ft	DSA‑SS enforces at 50,000 for its projects	§ 5.105.1
Minimum preservation if using reuse path	45 percent combined of structural elements + enclosure	Must be demonstrated in construction documents	§ 5.105.2 and § 5.105.2.1
Elements excluded from calculation	Window assemblies, insulation, structurally unsound/hazardous portions, remediated hazardous materials	Do not count toward the preserved percentage	§ 5.105.2
Very large additions exception	Combined additions ≥ 2× existing building area are not eligible to meet compliance via reuse	Cannot claim the reuse path for such large additions	§ 5.105.1 (Exception)

Exceptions & special cases

Large addition exclusion: A combined addition equal to two times the area or more of the existing building cannot use § 5.105.2 to demonstrate compliance — you must use another path. § 5.105.1 (Exception).
Alternative compliance allowed: The scope language in § 5.105.1 explicitly permits compliance by either § 5.105.2 (reuse) or the life‑cycle assessment alternatives § 5.409.2 or § 5.409.3; use of those alternatives may be appropriate when preserving 45% is impractical.
DSA projects: Projects under DSA‑SS follow the 50,000 sq ft threshold as stated in § 5.105.1; confirm DSA guidance for administration.
Voluntary Tier guidance: Appendix A5.105.2 contains voluntary Tier 1/2 reuse provisions (different percentages/requirements for Tier compliance); those are voluntary and sit in Appendix A, not the mandatory Chapter 5 provisions. Use Appendix A only when pursuing voluntary tiers.

Common mistakes

Treating the 45% rule as applying to all projects regardless of size — it only applies when the size triggers § 5.105.1 (thresholds above).
Counting window assemblies and insulation toward the preserved percentage — the code explicitly excludes them from the calculation. § 5.105.2.
Forgetting to include the required verification in the construction documents (file the worksheet or equivalent per § 5.105.2.1).
Assuming Appendix A reuse measures are mandatory — Appendix A5.105.2 is voluntary Tier material and has its own Tier verification language; do not conflate that with mandatory Chapter 5 requirements.
Trying to use the reuse path for an addition that is two times or more the area of the existing building — the exception in § 5.105.1 disallows that.

Worked example — applying the rule with numbers

Scenario (effective after 1/1/2026): an owner proposes an alteration where the combined altered floor area is 55,000 sq ft for an existing nonresidential building.

Threshold check:
- The project meets the 50,000 sq ft threshold in § 5.105.1, so either the reuse path (§ 5.105.2) or a life‑cycle alternative (§ 5.409.2/5.409.3) must be followed.
If choosing the reuse path:
- The project must maintain at least 45 percent combined of the building’s primary structural elements and enclosure. Example calculation:
  - Existing building gross floor area (for measuring existing elements) = 80,000 sq ft.
  - To meet 45%, preserved primary structure + enclosure must represent an equivalent of 36,000 sq ft (0.45 × 80,000 = 36,000).
  - If the design retains foundations and columns that serve 30,000 sq ft of the building and retains roof/wall framing and exterior finishes that serve an additional 9,000 sq ft (excluding windows and insulation which are excluded), the preserved total = 39,000 sq ft → 39,000 / 80,000 = 48.75% preserved → compliant with § 5.105.2.
- Document the calculation and evidence in the construction documents per § 5.105.2.1 (WS‑3 worksheet recommended).
If the preserved amount were only 30,000 sq ft (37.5%), the reuse path would fail and the project team must either:
- Increase preservation to meet 45%, or
- Pursue an approved life‑cycle alternative in § 5.409.2 or § 5.409.3 as allowed by § 5.105.1.

Note: this example is illustrative of the arithmetic. The code does not prescribe every technical measurement method here — use the construction documents and the noted worksheet (WS‑3) to demonstrate compliance.

Related CALGreen provisions

§ 5.105.1 — Scope and thresholds for deconstruction and reuse (controls applicability).
§ 5.105.2 — Reuse of existing building (minimum preservation percentage and excluded items).
§ 5.105.2.1 — Verification: construction‑document requirement to demonstrate compliance.
§ 5.409 — Life‑cycle assessment alternatives referenced as compliance options in § 5.105.1 (see 5.409.2 / 5.409.3).
§ 5.408 — Construction waste reduction, disposal and recycling (related C&D handling and documentation).
A5.105.2 (Appendix A) — Voluntary Tier 1 / Tier 2 reuse provisions and verification (separate voluntary paths).

Code references

Grounded in the retrieved California Green Building Standards Code (CALGreen) — click a citation to read the verbatim passage:

CALGreen § 5.102 High relevance — show source text
101||||||||X||||||||||||||| |5.102 Definitions||||||||X||||||||||||||| |5.105||||||||X||||||||||||||| |5.105.1 Scope||||||||X||||||||||||||| |5.106.4.2 and subsections||†||||||X||||||||||||||| |5.106.5.6 and subsections||†||||||X||||||||||||||| |5.106.8||||||||X||||||||||||||| |5.106.10||||||||X||||||||||||||| |5.106.12 and subsections||†||||||X|||||||||||||||

The state agency does not adopt sections identified with the following symbol: †

2025 CALIFORNIA GREEN BUILDING STANDARDS CODE 5-1

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5-2 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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5 NONRESIDENTIAL MANDATORY MEASURES

DIVISION 5.1 – PLANNING AND DESIGN

SECTION 5.101—GENERAL

5.101.1 Scope. The provisions of this chapter outline planning, design and development methods that include environmentally responsible site selection, building design, building siting and development to protect, restore and enhance the environmental quality of the site and respect the integrity of adjacent properties.

SECTION 5.102—DEFINITIONS

5.102.1 Definitions. The following terms are defined in Chapter 2.

CUTOFF LUMINAIRES.

TENANT-OCCUPANTS.

ZEV.

SECTION 5.103—SITE SELECTION (RESERVED)

SECTION 5.104—SITE PRESERVATION (RESERVED)

SECTION 5.105—DECONSTRUCTION AND REUSE OF EXISTING STRUCTURES

5.105.1 Scope.

[BSC-CG] Effective July 1, 2024, alteration(s) to existing building(s) where the combined altered floor area is 100,000 square feet or greater shall comply with either Section 5.105.2, 5.409.2, or 5.409.3. Addition(s) to existing building(s) where the total floor area combined with the existing building(s) is 100,000 square feet or greater shall comply with either Section 5.105.2, Section 5.409.2, or Section 5.409.3. Effective January 1, 2026, the combined floor area shall be 50,000 square feet or greater.

[DSA-SS] Alteration(s) to existing building(s) where the combined altered floor area is 50,000 square feet or greater shall comply with either Section 5.105.2, 5.409.2, or 5.409.3. 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 5.105.2, Section 5.409.2, or Section 5.409.3.

Exception [BSC-CG, DSA-SS]: 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.
CALGreen § 105.2 High relevance — show source text
1. 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.
2. 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.
3. 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

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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).

CALGreen § 301.3 High relevance — show source text

A5.602

CALGreen VERIFICATION GUIDELINES MANDATORY MEASURES CHECKLIST

Application: This checklist shall be used for nonresidential projects that meet one of the following: new construction, building additions of 1,000 square feet or greater, or building alterations with a permit valuation of $200,000 or more pursuant to Section 301.3 AND do not trigger a Tier 1 or Tier 2 requirement:

Y = Yes (section has been selected and/or included)

— N/A = Not Applicable (code section does not apply to the project mainly used for additions and alterations) O = Other (provide explanation)

[N] = New construction pursuant to Section 301.3

[A ] = Additions and/or Alterations pursuant to Section 301.3

CHAPTER 5 DIVISIONS	Col2	SECTION TITLE	CODE SECTION
DIVISION 5.1 Planning and Design	Mandatory	Deconstruction and reuse of existing structures, Scope with Exception	5.105.1
DIVISION 5.1 Planning and Design	Mandatory	Reuse of existing building & Verification of compliance with note	5.105.2 and 5.105.2.1
DIVISION 5.1 Planning and Design	Mandatory	Storm water pollution prevention for projects that disturb less than 1 acre of land	5.106.1 through 5.106.2
DIVISION 5.1 Planning and Design	Mandatory	Short-term bicycle parking (with exception)	5.106.4.1.1
DIVISION 5.1 Planning and Design	Mandatory	Long-term bicycle parking	5.106.4.1.2 through 5.106.4.1.2.3
DIVISION 5.1 Planning and Design	Mandatory	Electric vehicle (EV) charging [N] with Section 5.106.3.1, 5.106.5.3.2 and associated Table 5.106.5.3.1 OR Independently Power Allocation Method: Section 5.106.5.3.6 and associated Table 5.106.5.3.6	5.106.5.3.1, 5.106.5.3.2, Table 5.106.5.3.1, 5.106.5.3.2.1, 5.106.5.3.2.2, 5.106.5.3.2.3, 5.106.5.3.2.4, 5.106.5.3.3, 5.106.5.3.4 and 5.106.5.3.5 OR 5.106.5.3.3, 5.106.5.3.4, 5.106.5.3.5, 5.106.5.3.6,

CALGreen § 103.2.1 High relevance — show source text
A5.103.2.1 Brownfield redevelopment. Develop a site documented as contaminated by means of an ASTM E1903-11 Phase II Environmental Site Assessment or on a site defined as a brownfield by a local, state or federal government agency. The site must be fully remediated in accordance with EPA regulations to the level required of the anticipated land use.

SECTION A5.104—SITE PRESERVATION

A5.104.1 Reduce development footprint and optimize open space. Optimize open space on the project site in accordance with Sections A5.104.1.1, A5.104.1.2 or A5.104.1.3.

A5.104.1.1 Local zoning requirement in place. Exceed the zoning’s open space requirement for vegetated open space on the site by 25 percent.

A5.104.1.2 No local zoning requirement in place. Provide vegetated open space area adjacent to the building equal to the building footprint area.

A5.104.1.3 No open space required in zoning ordinance. Provide vegetated open space equal to 20 percent of the total project site

area.

SECTION A5.105—DECONSTRUCTION AND REUSE OF EXISTING STRUCTURES

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.
CALGreen § 5.103 High relevance — show source text
ZEV.

SECTION 5.103—SITE SELECTION (RESERVED)

SECTION 5.104—SITE PRESERVATION (RESERVED)

SECTION 5.105—DECONSTRUCTION AND REUSE OF EXISTING STRUCTURES

5.105.1 Scope.

[BSC-CG] Effective July 1, 2024, alteration(s) to existing building(s) where the combined altered floor area is 100,000 square feet or greater shall comply with either Section 5.105.2, 5.409.2, or 5.409.3. Addition(s) to existing building(s) where the total floor area combined with the existing building(s) is 100,000 square feet or greater shall comply with either Section 5.105.2, Section 5.409.2, or Section 5.409.3. Effective January 1, 2026, the combined floor area shall be 50,000 square feet or greater.

[DSA-SS] Alteration(s) to existing building(s) where the combined altered floor area is 50,000 square feet or greater shall comply with either Section 5.105.2, 5.409.2, or 5.409.3. 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 5.105.2, Section 5.409.2, or Section 5.409.3.

Exception [BSC-CG, DSA-SS]: 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.

5.105.2 Reuse of existing building. An alteration or addition to an existing building shall maintain at a minimum 45 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.

5.105.2.1 Verification of compliance. Documentation shall be provided in the construction documents to demonstrate compliance with Section 5.105.2.

Note: Sample Worksheet WS-3 in Chapter 8 may be used to assist in documenting compliance with this section.

5.105.3 Deconstruction (Reserved).

SECTION 5.106—SITE DEVELOPMENT

5.106.1 Stormwater pollution prevention for projects that disturb less than one acre of land. Newly constructed projects and additions which disturb less than one acre of land and are not part of a larger common plan of development or sale shall prevent the pollution of stormwater runoff from the construction activities through one or more of the following measures:

5.106.1.1 Local ordinance. Comply with a lawfully enacted stormwater management and/or erosion control ordinance.
CALGreen § 5.410.2 High relevance — show source text
Commissioning Commissioning Appendix A6.1 (OSHPD) A5.204, 5.410.2 Commissioning plan 5.410.2.3 Commissioning report 5.410.2.6 Construction Waste Reduction, Disposal and Recycling Appendix A6.1 (OSHPD) A5.408, 4.408, 5.408 Construction waste management 4.408.1, 5.408.1 Construction waste management plan 4.408.2, 5.408.1.1 Enhanced construction waste reduction

A4.408.1, A5.408.3.1 Excavated soil and land clearing debris 5.408.3

Deconstruction and Reuse of Existing Materials 4.105, A4.105 Reuse of materials A4.105.2

Deconstruction and Reuse of Existing Structures 5.105, A5.105 (Reserved) 4.105 Reuse of existing building 5.105.2, Chapter 8 (WS-3), A5.105.2, Chapter 8 (WS-6) Definitions Chapter 2 Durability, Enhanced and Reduced Maintenance 4.406, A4.406, A5.406 Choice of materials A5.406.1

Electric Vehicle (EV) Charging 4.106.4, 5.106.5.3, 5.106.5.5, 5.106.5.6, A4.106.8,

A5.106.5.3

INDEX

Alterations and additions 4.106.4.3, 5.106.5.4, 5.106.5.6.4 Electric vehicle charging stations (EVCS) 5.106.5.3.2, 5.106.5.6.2 EVCS alternative compliance 5.106.5.6.3 EVCS signage 5.106.5.3.5 Power allocation method 5.106.5.3.6, Table 5.106.5.3.6, A5.106.5.3.2 Tier 1, Table 5.106.5.3.2 Tier 1, A5.106.5.3.4 Tier 2, Table 5.106.5.3.4 Tier 2 Elevators, Escalators and Other Equipment A5.212 Energy Efficiency 4.201.1, A4.203.1, A4.204.1 Commissioning Appendix A6.1 (OSHPD) A5.204.4

ENERGY STAR equipment and appliances Appendix A6.1(OSHPD), A4.403.3, A5.204.1 General 4.201, 5.201, A5.201 Performance approach A4.203, A5.203 Outdoor lighting A5.203.1.1.1 Prescriptive approach Appendix A6.1(OSHPD), 203.3.1.2 Alterations to existing buildings A4.204.1, A4.204.1.2, A5.204.1,

A5.204.1.1 Energy Efficient Steel Framing A5.213 Environmental Comfort 4.507, 5.507,

A5.507

CALGreen § 301.3 High relevance — show source text

Y = Yes (section has been selected and/or included) N = No (section has not been selected and/or included) O = Other (provide explanation)

[N] = New construction pursuant to Section 301.3

[A] = Additions and/or Alterations pursuant to Section 301.3

CHAPTER 5 DIVISIONS	Col2	SECTION TITLE	CODE SECTION
~~DIVISION 5.1~~ Planning and Design (continued)	Mandatory	Deconstruction and reuse of existing structures, Scope with Exception	5.105.1
~~DIVISION 5.1~~ Planning and Design (continued)	Mandatory	Reuse of existing building & Verification of compliance with note	5.105.2 and 5.105.2.1
~~DIVISION 5.1~~ Planning and Design (continued)	Mandatory	Storm water pollution prevention for projects that disturb less than 1 acre of land	5.106.1 through 5.106.2
~~DIVISION 5.1~~ Planning and Design (continued)	Mandatory	Short-term bicycle parking	5.106.4.1.1
~~DIVISION 5.1~~ Planning and Design (continued)	Mandatory	Long-term bicycle parking	5.106.4.1.2 through 5.106.4.1.5
~~DIVISION 5.1~~ Planning and Design (continued)	Tier 1 Prerequisite	Designated parking—35% of parking capacity with future charging spaces, parking stall markings and vehicle designation	A5.106.5.1, A5.106.5.1.1, A5.106.5.1.3, A5.106.5.1.4, A5.106.5.1.5
~~DIVISION 5.1~~ Planning and Design (continued)	Tier 1 Prerequisite	Electric vehicle (EV) charging [N] with Section 5.106.3.1, Section 5.106.5.3.2 and associated Table A5.106.5.3.1 Tier 1 OR Power Allocation Method: Section A5.106.5.3.2 and associated Table A5.106.5.3.2 Tier 1	5.106.5.3.1, 5.106.5.3.2, Table A5.106.5.3.1 Tier 1, 5.106.5.3.2.1, 5.106.5.3.2.2, 5.106.5.3.2.3, 5.106.5.3.2.4, _5.106.5.3.3,

CALGreen § 103.2 High relevance — show source text
An infill site is selected.
2. A greyfield site is selected.
3. An EPA-recognized Brownfield site is selected.||
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| |A4.103.2 Facilitate community connectivity by one of the following
methods:
1. Locate project within a1/4-mile true walking distance of at least 4
basic services;
2. Locate project within1/2-mile true walking distance of at least 7
basic services;
3. Other methods increasing access to additional resources.||
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| |Site Preservation||||||| |A4.104.1An individual with oversight responsibility for the project
has participated in an educational program promoting
environmentally friendly design or development and has provided
training or instruction to appropriate entities.||||||| |Deconstruction and Reuse of Existing Materials||||||| |A4.105.2 Existing buildings are disassembled for reuse or recycling of
building materials. The proposed structure utilizes at least one of the
following materials which can be easily reused:
1. Light fixtures
2. Plumbing fixtures
3. Doors and trim
4. Masonry
5. Electrical devices
6. Appliances
7. Foundations or portions of foundations||||||| |Site Development||||||| |4.106.2A plan is developed and implemented to manage storm water
drainage during construction.||||||| |4.106.3Construction plans shall indicate how site grading or a
drainage system will manage all surface water flows to keep water
from entering buildings.||||||| |4.106.4.1Provide capability for electric vehicle charging for one- and
two-family dwellings; townhouses with attached private garages in
accordance with Section 4.106.4.1.||||||| |4.106.4.2 Provide capability for electric vehicle charging for
multifamily dwellings and hotels/motels in accordance with Sections
4.106.4.2.2 and 4.106.4.2.6.||||||| |4.106.4.3 Provide capability for electric vehicle charging for existing
parking lots or new parking lots for existing residential buildings,
CALGreen § 303.3 High relevance — show source text
Additions and Alterations See Non-

residential Additions and Alterations Administration Chapter 1 Air Quality and Exhaust, Indoor – see Indoor Air Quality and Exhaust Appliances A4.303.3, A5.303.3, Appendix A6.1 (OSHPD) A5.207 Application Checklists A4.602, A5.602, Appendix A6.1 (OSHPD)

Bird Friendly Building Design A5.107 Building Envelope A4.204, Appendix A6.1 (OSHPD) A5.205 Building orientation Appendix A6.1(OSHPD), A5.204.6 Fenestration products and exterior doors Appendix A6.1(OSHPD), A5.205.1 Insulation and roofing products Appendix A6.1(OSHPD), A5.205.3 Life cycle assessment 5.409, A5.409 Building Maintenance and Operation 4.410, 5.410 Commissioning 5.410.2, A5.410.3 Sample compliance forms and templates Chapter 8 Operation and maintenance manual 4.410.1, 5.410.4.5 Recycling by occupants Appendix A6.1(OSHPD), A5.410, 5.410.1 Testing and adjusting 5.410.4

Commissioning Commissioning Appendix A6.1 (OSHPD) A5.204, 5.410.2 Commissioning plan 5.410.2.3 Commissioning report 5.410.2.6 Construction Waste Reduction, Disposal and Recycling Appendix A6.1 (OSHPD) A5.408, 4.408, 5.408 Construction waste management 4.408.1, 5.408.1 Construction waste management plan 4.408.2, 5.408.1.1 Enhanced construction waste reduction

A4.408.1, A5.408.3.1 Excavated soil and land clearing debris 5.408.3

Deconstruction and Reuse of Existing Materials 4.105, A4.105 Reuse of materials A4.105.2

Deconstruction and Reuse of Existing Structures 5.105, A5.105 (Reserved) 4.105 Reuse of existing building 5.105.2, Chapter 8 (WS-3), A5.105.2, Chapter 8 (WS-6) Definitions Chapter 2 Durability, Enhanced and Reduced Maintenance 4.406, A4.406, A5.406 Choice of materials A5.406.1

Electric Vehicle (EV) Charging 4.106.4, 5.106.5.3, 5.106.5.5, 5.106.5.6, A4.106.8,

A5.106.5.3

INDEX

CALGreen § 405.4 High relevance — show source text

From Division A5.4,

a. Comply with recycled content of 15 percent of materials based on estimated total cost, or use two products from Table A5.405.4 for at least 75 percent by cost in Section A5.405.4.1. b. Comply with the 80-percent reduction in construction and demolition waste in Section A5.408.3.1. c. Comply with three elective measures selected from this division.

From Division A5.5,

a. Comply with resilient flooring systems for 100 percent of resilient flooring in Section A5.504.4.7.1. Exception: Allowance may be permitted in Tier 2 for up to 5-percent specialty purpose flooring. b. Comply with thermal insulation meeting 2009 CHPS low-emitting materials list and no added formaldehyde in Section A5.504.4.8.1.

c. Comply with three elective measures selected from this division. 6. Comply with three additional elective measures selected from any division.

1 Cool roof is required for compliance with Tiers 1 and 2 and may be used to meet energy standards in Part 6, exceed energy standards and to mitigate heat island effect.

A5.601.4 Compliance verification. Compliance with Section A5.601.2 or A5.601.3 shall be as required in Chapter 7 of this code. Compliance documentation shall be made part of the project record as required in Section 5.410.2 or 5.410.3.

2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A5-43

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APPENDIX A5 — NONRESIDENTIAL VOLUNTARY MEASURES

A5.602

CALGreen VERIFICATION GUIDELINES MANDATORY MEASURES CHECKLIST

Y = Yes (section has been selected and/or included)

— N/A = Not Applicable (code section does not apply to the project mainly used for additions and alterations) O = Other (provide explanation)

[N] = New construction pursuant to Section 301.3

[A ] = Additions and/or Alterations pursuant to Section 301.3

CHAPTER 5 DIVISIONS	Col2	SECTION TITLE	CODE SECTION
DIVISION 5.1 Planning and Design	Mandatory	Deconstruction and reuse of existing structures, Scope with Exception	5.105.1
DIVISION 5.1 Planning and Design	Mandatory	Reuse of existing building & Verification of compliance with note	5.105.2 and 5.105.2.1
DIVISION 5.1 Planning and Design	Mandatory	Storm water pollution prevention for projects that disturb less than 1 acre of land	5.106.

CALGreen § 602.1 Medium relevance — show source text

2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A5-39

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APPENDIX A5-40 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

A5 NONRESIDENTIAL VOLUNTARY MEASURES

DIVISION A5.6 – VOLUNTARY TIERS

SECTION A5.601—CALGreen TIER 1 AND TIER 2	Col2	Col3	Col4
TABLE A5.601 NONRESIDENTIAL BUILDINGS: Green Building Standards Code Proposed Performance Approach Note: This table is intended only as an aid in illustrating the nonresidential tier structure (Refer to Checklists A5.602, A5.602.1 and A5.602.2 for CALGreen verification guidelines for Mandatory Checklist, Tier 1 Checklist and Tier 2 Checklist.)	TABLE A5.601 NONRESIDENTIAL BUILDINGS: Green Building Standards Code Proposed Performance Approach Note: This table is intended only as an aid in illustrating the nonresidential tier structure (Refer to Checklists A5.602, A5.602.1 and A5.602.2 for CALGreen verification guidelines for Mandatory Checklist, Tier 1 Checklist and Tier 2 Checklist.)	TABLE A5.601 NONRESIDENTIAL BUILDINGS: Green Building Standards Code Proposed Performance Approach Note: This table is intended only as an aid in illustrating the nonresidential tier structure (Refer to Checklists A5.602, A5.602.1 and A5.602.2 for CALGreen verification guidelines for Mandatory Checklist, Tier 1 Checklist and Tier 2 Checklist.)	TABLE A5.601 NONRESIDENTIAL BUILDINGS: Green Building Standards Code Proposed Performance Approach Note: This table is intended only as an aid in illustrating the nonresidential tier structure (Refer to Checklists A5.602, A5.602.1 and A5.602.2 for CALGreen verification guidelines for Mandatory Checklist, Tier 1 Checklist and Tier 2 Checklist.)
CATEGORY	ENVIRONMENTAL PERFORMANCE GOAL	TIER 1	TIER 2
All	Minimum Mandatory (See Mandatory Checklist)	Meet all of the provisions of Chapter 5 (See Tier 1 Checklist)	Meet all of the provisions of Chapter 5 (See Tier 2 Checklist)
DIVISION 5.1 Planning and Design	Reuse of existing building	See Section A5.105.1 and Section A5.105.2 requirements	See Section A5.105.1 and Section A5.105.2 requirements
DIVISION 5.1 Planning and Design	Designated Parking for Fuel Efficient Vehicles (Tier 1 and Tier 2 only)	Approx. 35% of total spaces	Approx. 50% of total spaces
DIVISION 5.1 Planning and Design	Electric Vehicle Charging	Approx. 30% of total spaces	Approx. 45% of total spaces
**DIVISION 5.

CALGreen § 301.3 Medium relevance — show source text

Select the required number of additional electives from those categories shown on the table below and add a “ Y ” on the selected elective and add an “ N ” on the rest.

Count the total number of Tier 2 prerequisite measures plus the additional electives and write down the total number at the end of the checklist. Determine if the required number of Tier 2 measures have been selected to achieve Tier 2 compliance.

Y = Yes (section has been selected and/or included) N = No (section has not been selected and/or included) O = Other (provide explanation)

[N] = New construction pursuant to Section 301.3

[A] = Additions and/or Alterations pursuant to Section 301.3

CHAPTER 5 DIVISIONS	Col2	SECTION TITLE	CODE SECTION
DIVISION 5.1 Planning and Design (continued)	Mandatory	Deconstruction and reuse of existing structures, Scope with Exception	5.105.1
DIVISION 5.1 Planning and Design (continued)	Mandatory	Reuse of existing building & Verification of compliance with note	5.105.2 and 5.105.2.1
DIVISION 5.1 Planning and Design (continued)	Mandatory	Storm water pollution prevention for projects that disturb less than 1 acre of land	5.106.1 through 5.106.2
DIVISION 5.1 Planning and Design (continued)	Mandatory	Short-term bicycle parking	5.106.4.1.1
DIVISION 5.1 Planning and Design (continued)	Mandatory	Long-term bicycle parking	5.106.4.1.2 through 5.106.4.1.5
DIVISION 5.1 Planning and Design (continued)	Tier 2 Prerequisite	Designated parking—50% of parking capacity with future charging spaces, parking stall markings and vehicle designation	A5.106.5.1, A5.106.5.1.2, A5.106.5.1.3, A5.106.5.1.4, A5.106.5.1.5
DIVISION 5.1 Planning and Design (continued)	Tier 2 Prerequisite	Electric vehicle (EV) charging [N] with Section 5.106.3.1, Section 5.106.5.3.2 and associated Table A5.106.5.3.3 Tier 2 OR Power Allocation Method: Section A5.106.5.3.4 and associated Table A5.106.5.3.4 Tier 2	5.106.5.3.1, 5.106.5.3.2, _Table A5.106.5.

Frequently asked questions

Do these reuse rules apply to small renovation projects?

No — the mandatory reuse requirement only applies when the project meets the size thresholds in § 5.105.1 (100,000 sq ft starting 7/1/2024, dropping to 50,000 sq ft on 1/1/2026, with DSA‑SS at 50,000). Smaller projects do not trigger the mandatory Chapter 5 reuse minimum.

What exactly counts toward the **45%** preservation calculation?

The code counts preserved primary structural elements (foundations; columns, beams, walls, floors; lateral elements) and existing building enclosure (roof framing, wall framing, exterior finishes). Window assemblies, insulation, structurally unsound/hazardous portions, and remediated hazardous materials are excluded. See § 5.105.2.

Where do I show proof of compliance?

Provide documentation in the construction documents demonstrating compliance with § 5.105.2, per § 5.105.2.1. The code notes Worksheet WS‑3 in Chapter 8 as an example form.

Can I choose a life‑cycle assessment path instead of preserving 45%?

Yes. § 5.105.1 allows projects that meet the thresholds to comply by § 5.105.2 (reuse) or § 5.409.2/5.409.3 (life‑cycle alternatives). Select the path appropriate to the project and document accordingly.

If my addition is massive (≥ 2× existing area), can I still use the reuse path?

No — the exception in § 5.105.1 disallows using § 5.105.2 when the combined addition(s) equal two times the area or more of the existing building.

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Related in the CALGreen

Short-term and long-term bicycle parking requirements

Electric vehicle (EV) charging and power-allocation requirements and tables

Stormwater pollution prevention for projects that disturb less than 1 acre

Planning & Design (Division 5.1)

California Green Building Standards Code (CALGreen)

Reuse and deconstruction requirements for existing nonresidential buildings

What the code requires — plain English

Requirements in detail

1) Scope & applicability (when this applies)

2) Reuse minimums (what must be preserved)

3) Verification / documentation

Quick reference decision table

Exceptions & special cases

Common mistakes

Worked example — applying the rule with numbers

Related CALGreen provisions

Code references

5 NONRESIDENTIAL MANDATORY MEASURES

INDEX

INDEX

A5 NONRESIDENTIAL VOLUNTARY MEASURES

Frequently asked questions

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