CALGreen · California Green Building Standards Code (CALGreen)

Cement reduction and recycled content thresholds for Tier 1/Tier 2

For homeowners: To meet CALGreen Tier targets you must reduce cement in foundation mixes by 20% (Tier 1) or 25% (Tier 2) and ensure recycled-content materials equal 10% (Tier 1) or 15% (Tier 2) of your project’s material cost; structural framing is excluded and concrete with SCMs has a special RCV method.

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

The code requires reduced cement use in foundation mixes and a minimum project recycled content value (RCV) tied to total material cost for Tier compliance. Specifically, § A4.403.2 mandates not less than a 20% cement reduction for Tier 1 and not less than a 25% cement reduction for Tier 2 in foundation mix design. § A4.405.3.1 requires a total RCV of at least 10% (Tier 1) or 15% (Tier 2) of the total material cost of the project.

Most important rule: Reduce cement in foundation mixes by 20% (Tier 1) or 25% (Tier 2), and reach a projectwide RCV equal to 10% (Tier 1) or 15% (Tier 2) of total material cost (structural frame excluded).

Requirements in detail

Key defined terms (first mention bolded)

  • Tier 1 and Tier 2 — voluntary/residential tiers in Appendix A4 that specify progressively stricter measures.
  • § A4.403.2 — the controlling section for cement reduction in foundation mix design.
  • § A4.405.3.1 — the controlling section for recycled content value (RCV) requirements and calculation method.
  • Total material cost — defined calculation basis used to determine required RCV; can be calculated by the simplified or detailed method per § A4.405.3.1.1.
  • Supplementary Cementitious Materials (SCMs) — fly ash, slag, silica fume, rice hull ash, etc., listed as common cement replacements in § A4.403.2.

Quick reference table — decision-relevant values

Measure Tier 1 Tier 2 Code reference
Cement reduction in foundation mix design ≥ 20% reduction in cement use ≥ 25% reduction in cement use § A4.403.2
Total RCV (project) ≥ 10% of total material cost ≥ 15% of total material cost § A4.405.3.1
Total material cost — simplified Project sq ft × BVD valuation × 45% = Total material cost Same § A4.405.3.1.1
Total RCV calculation Sum of RCV of materials + assemblies (dollars) or percent of total material cost Same § A4.405.3.1.2
Concrete (alternate RCV method) For concrete with SCMs, multiply percent recycled content by cost of cementitious materials only (not total concrete cost) Same § A4.405.3.1.5

What must be done (stepwise)

  1. For foundations: design your foundation concrete mix to reduce cement content relative to a conventional mix by 20% (Tier 1) or 25% (Tier 2) using SCMs or other alternatives listed in the code. § A4.403.2 identifies common SCMs (fly ash, slag, silica fume, rice hull ash).
  2. For recycled content compliance: calculate Total Material Cost using either the simplified method (square footage × BVD valuation × 45%) or the detailed method (sum of estimated/actual material costs). Then compute required Total RCV = Total Material Cost × 10% (Tier 1) or × 15% (Tier 2). § A4.405.3.1 and § A4.405.3.1.1 explain the formulas and methods.
  3. Compute each material’s RCV using postconsumer + 0.5×preconsumer (see § A4.405.3.1.3) and assemblies per the assembly rules in § A4.405.3.1.4. Add RCV of materials and assemblies to get Total RCV (dollars or percent) and compare to required threshold.

Exceptions & special cases

  • The code permits an alternate method for concrete: when SCMs are used, you may calculate recycled content by applying the recycled-content percent to the cost of the cementitious materials only, not the total cost of the concrete product. This changes the RCV basis for concrete products and can materially affect the RCV contribution from concrete. § A4.405.3.1.5.
  • Structural frame materials (load-bearing studs, plates, sills, columns, beams, joists, rafters, trusses) are excluded from recycled-content calculations for RCV purposes. See § A4.405.3.1 notes.
  • The enforcing agency may allow reduced cement only “as allowed by the enforcing agency” — local adoption/enforcement rules may apply; verify with the local enforcing agency. § A4.403.2.

Common mistakes

  • Treating the RCV percentage as a percentage of the entire project cost (fees, labor, appliances) instead of total material cost. The code defines total material cost and prescribes what to include/exclude. § A4.405.3.1.1.
  • Including structural-frame items in RCV calculations — structural frame is explicitly excluded. § A4.405.3.1.
  • Applying the recycled-content percent to the total concrete cost when SCMs are used (instead of using the alternate method that applies percent to cementitious materials only). See § A4.405.3.1.5.
  • Failing to document calculations and supplier certificates: sample forms and documentation tools are referenced in the code and recommended for verification. § A4.405.3.1 notes.

Worked example — applying the rule with numbers (illustrative)

Note: the code prescribes the formulae but does not fix local valuation numbers; the example below uses assumed valuation figures for demonstration only. The code allows using the ICC Building Valuation Data (BVD) or other values approved by the enforcing agency. § A4.405.3.1.1.

Scenario (assumptions for illustration)

  • Residence size: 2,000 sq ft
  • Assumed square-foot valuation (BVD or local): $200 / sq ft (assumed for example only — not in code)
  • Use the simplified method: Total material cost = 2,000 × $200 × 45% = $180,000. § A4.405.3.1.1.

Required Total RCV

  • Tier 1 RCV = $180,000 × 10% = $18,000. § A4.405.3.1.
  • Tier 2 RCV = $180,000 × 15% = $27,000. § A4.405.3.1.

Concrete / cement example (assumptions)

  • Suppose the baseline cement used for foundations is an aggregate of materials that results in 3,000 lb total cement used across the foundation work (assumed baseline for illustration only — code does not specify baseline mass). To comply:
    • Tier 1: required cement reduction = 20% → cement reduced = 3,000 × 20% = 600 lb reduction (new cement = 2,400 lb). § A4.403.2.
    • Tier 2: required cement reduction = 25% → cement reduced = 3,000 × 25% = 750 lb reduction (new cement = 2,250 lb). § A4.403.2.

How concrete contributes to RCV (use of alternate concrete method)

  • If you replace cement with SCMs (e.g., fly ash) and the manufacturer certifies that the cementitious portion of the mix is, say, 30% recycled content, use § A4.405.3.1.5: multiply the 30% by the cost of the cementitious materials only (not total concrete cost) to compute RCV contribution from that concrete. This can be easier to document and may yield a smaller or larger RCV contribution depending on cementitious cost proportion.

Documentation

  • Retain supplier product data showing postconsumer and preconsumer recycled content or a single manufacturer-reported recycled content (rules for counting pre- vs postconsumer content are in § A4.405.3.1.3). Use sample forms available from the agency to document calculations if desired.

Related provisions

  • § A4.405.3.1.5 — Alternate method for calculating recycled content in concrete with SCMs.
  • § A4.405.3.1.1 — Total material cost definition and the simplified/detailed methods.
  • § A4.405.3.1.2–.4 — Equations and methods to determine Total RCV, RCV of materials (RCV_M), and assemblies (RCV_A).
  • § A4.408.1 — Construction waste reduction thresholds (related material-conservation measure for Tier compliance).
  • § A4.602 — Residential occupancies application checklist (shows how A4.403.2 and A4.405.3.1 feed into Tier checklists).

Code references

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

  • CALGreen § 3.1. High relevance — show source text
    1. From Division A4.3, Water Efficiency and Conservation. 3.1. Comply with at least three elective measures selected from Division A4.3.
    2. From Division A4.4, Material Conservation and Resource Efficiency. 4.1. Comply with the 25 percent cement reduction requirements in Section A4.403.2. 4.2. Comply with the 15 percent recycled content requirements in Section A4.405.3.1. 4.3. Comply with the 75 percent reduction in construction waste in Section A4.408.1. 4.4. Comply with at least four elective measures selected from Division A4.4.
    3. From Division A4.5, Environmental Quality. 5.1. Comply with the 100 percent resilient flooring systems requirements in Section A4.504.2. 5.2. Comply with the thermal insulation requirements for Tier 1 and Tier 2 in Section A4.504.3. 5.3. Comply with at least one elective measure selected from Division A4.5.

    Note: The Residential Occupancies Application Checklist contained in Section A4.602 may be used to show which elective measures are selected.

    APPENDIX A4-22 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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    DIVISION A4.6 – TIER 1 AND TIER 2

    SECTION A4.602 — RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST

    FEATURE OR MEASURE LEVELS
    APPLICANT TO SELECT ELECTIVE MEASURES    		 Col3 Col4 VERIFICATIONS
    ENFORCING AGENCY TO SPECIFY
    VERIFICATION METHOD    		 Col6 Col7
    FEATURE OR MEASURE Mandatory Prerequisites and electives1 Prerequisites and electives1 Enforcing
    Agency

    All    		 Installer or
    Designer

    All    		 Third
    party

    All
    FEATURE OR MEASURE Mandatory Tier 1 Tier 2 Tier 2 Tier 2 Tier 2
    PLANNING AND DESIGN
    Site Selection
    A4.103.1 A site which complies with at least one of the following
    characteristics is selected:
    1. An infill site is selected.
    2. A greyfield site is selected.
    3. An EPA-recognized Brownfield site is selected.









    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.
  • CALGreen § 404.1 High relevance — show source text

    ** Not less than a 20 percent reduction in cement use.
    **Tier 2.**Not less than a 25 percent reduction in cement use.||2|2|||| |Efficient Framing Techniques||||||| |A4.404.1 Beams and headers and trimmers are the minimum size to
    adequately support the load.||||||| |A4.404.2Building dimensions and layouts are designed to minimize
    waste.||||||| |A4.404.3Use premanufactured building systems to eliminate solid
    sawn lumber whenever possible.||||||| |A4.404.4 Material lists are included in the plans which specify
    material quantity and provide direction for on-site cuts.||||||| |Material Sources||||||| |A4.405.1 One or more of the following building materials, that do not
    require additional resources for finishing are used:
    1. Exterior trim not requiring paint or stain
    2. Windows not requiring paint or stain
    3. Siding or exterior wall coverings which do not require paint or
    stain||||||| |A4.405.2 Floors that do not require additional coverings are used
    including but not limited to stained, natural or stamped concrete
    floors.||||||| |A4.405.3Postconsumer or preconsumer recycled content value (RCV)
    materials are used on the project.
    **Tier 1.**Not less than a 10 percent recycled content value.
    **Tier 2.**Not less than a 15 percent recycled content value.||2
    |2
    |
    |
    |
    | |A4.405.4Renewable source building products are used.||||||| |Enhanced Durability and Reduced Maintenance||||||| |4.406.1 Annular spaces around pipes, electric cables, conduits or
    other openings in plates at exterior walls shall be protected against
    the passage of rodents by closing such openings with cement mortar,
    concrete masonry or similar method acceptable to the enforcing
    agency.||||||| |Water Resistance and Moisture Management||||||| |A4.407.1Install foundation and landscape drains.||||||| |A4.407.2Install gutter and downspout systems to route water at least
    5 feet away from the foundation or connect to landscape drains which
    discharge to a dry well, sump, bioswale, rainwater capture system or
    other approved on-site location.

  • CALGreen § 402.1 High relevance — show source text

    SECTION A4.401—GENERAL (RESERVED)

    SECTION A4.402—DEFINITIONS

    A4.402.1 Definitions. The following terms are defined in Chapter 2.

    ASSEMBLY (ASSEMBLY PRODUCT).

    POSTCONSUMER CONTENT.

    PRECONSUMER (OR POSTINDUSTRIAL) CONTENT.

    PROPORTIONAL RECYCLED CONTENT (PRC M ).

    RECYCLED CONTENT (RC).

    RECYCLED CONTENT VALUE (RCV).

    Assembly products (RCV A ). Materials (RCV M ).

    SECTION A4.403—FOUNDATION SYSTEMS

    A4.403.1 Frost protected foundation systems. As allowed by local conditions, utilize a Frost-Protected Shallow Foundation (FPSF) in compliance with the California Residential Code (CRC). When an FPSF foundation system is installed, the manual required by Section 4.410.1 shall include instructions to the owner or occupant regarding the necessity for heating the structure as required in Section R403.3 of the California Residential Code.

    A4.403.2 Reduction in cement use. As allowed by the enforcing agency, cement used in foundation mix design shall be reduced as follows:

    Tier 1. Not less than a 20 percent reduction in cement use.

    Tier 2. Not less than a 25 percent reduction in cement use.

    Note: Products commonly used to replace cement in concrete mix designs include, but are not limited to:

    1. Fly ash.

    2. Slag.

    3. Silica fume.

    4. Rice hull ash.

    SECTION A4.404—EFFICIENT FRAMING TECHNIQUES

    A4.404.1 Lumber size. Beams, headers and trimmers are sized and installed as specified in Chapter 23 of the California Building Code, or Chapter 6 of the California Residential Code, as applicable. Other calculations acceptable to the enforcing agency which use the minimum size member for the tributary load shall be acceptable.

    A4.404.2 Dimensions and layouts. Building dimensions and layouts are designed to minimize waste by one or more of the following measures in at least 80 percent of the structure:

    1. Building design dimensions in 2-foot increments are used.
    2. Windows and doors are located at regular 16 ″ or 24 ″ stud positions.
    3. Other methods acceptable to the enforcing agency.

    A4.404.3 Building systems. Use premanufactured building systems to eliminate solid sawn lumber whenever possible. One or more of the following premanufactured building systems is used:

    1. Composite floor joist or premanufactured floor framing system.
    2. Composite roof rafters or premanufactured roof framing system.
    3. Panelized (SIPS, ICF or similar) framing systems.
    4. Other methods approved by the enforcing agency.

    A4.404.4 Pre-cut materials and details. Material lists are included in the plans which specify the material quantity and provide direction for on-site cuts to be made from the material provided. Material lists and direction shall be provided for the following systems:

    1. Floor framing.
    2. Wall framing.
    3. Ceiling and roof framing.
    4. Structural panels and roof sheathing.

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-15

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  • CALGreen § 101.7 High relevance — show source text

    As specified in Section 101.7, additional prerequisite measures may be included by the enforcing agency to address specific local environmental conditions and may be listed in the Innovative Concepts and Local Environmental Conditions portions of the checklist.

    A4.601.3 Elective measures. In addition to the required measures, Tier 1 and Tier 2 buildings must incorporate at least the number of elective measures specified in Sections A4.601.4.2 and A4.601.5.2.

    A4.601.4 Tier 1. To achieve Tier 1 status a project must comply with the following:

    A4.601.4.1 Mandatory measures for Tier 1. The project shall meet or exceed all of the mandatory measures in Chapter 4, Divisions 4.1 through 4.5 and Chapter 7 as applicable.

    A4.601.4.2 Prerequisite and elective measures for Tier 1. In addition to the mandatory measures, compliance with the following prerequisite and elective measures from Appendix A4 is also required to achieve Tier 1 status:

    1. From Division A4.1, Planning and Design. 1.1. Comply with the topsoil protection requirements in Section A4.106.2.3. 1.2. Comply with the 20 percent permeable paving requirements in Section A4.106.4. 1.3. Comply with the cool roof requirements in Section A4.106.5. 1.4. Comply with the Tier 1 electric vehicle (EV) charging requirements in Section A4.106.8. 1.5. Comply with at least two elective measures selected from Division A4.1.

    2. From Division A4.2, Energy Efficiency. 2.1. For newly constructed low-rise residential buildings, comply with the energy efficiency requirements in Sections A4.203.1, A4.203.1.1, Table A4.203.1.1, A4.203.1.2 and A4.203.1.3.

    3. From Division A4.3, Water Efficiency and Conservation. 3.1. Comply with at least two elective measures selected from Division A4.3.

    4. From Division A4.4, Material Conservation and Resource Efficiency. 4.1. Comply with the 20 percent cement reduction requirements in Section A4.403.2. 4.2. Comply with the 10 percent recycled content requirements in Section A4.405.3.1. 4.3. Comply with the 65 percent reduction in construction waste in Section A4.408.1. 4.4. Comply with at least two elective measures selected from Division A4.4.

    5. From Division A4.5, Environmental Quality. 5.1. Comply with the 90 percent resilient flooring systems requirements in Section A4.504.2. 5.2. Comply with the thermal insulation requirements for Tier 1 in Section A4.504.3. 5.3. Comply with at least one elective measure selected from Division A4.5.

    Note: The Residential Occupancies Application Checklist contained in Section A4.602 may be used to show which elective measures are selected.

    A4.601.5 Tier 2. To achieve Tier 2 status a project must comply with the following.

    Note: The measures necessary to achieve Tier 2 status are very stringent. Cities, counties, and cities and counties considering adoption of Tier 2 as mandatory should carefully consider the stringency of each measure and ensure that the measures are achievable in their location.

  • CALGreen § 405.1 High relevance — show source text

    SECTION A4.405—MATERIAL SOURCES

    A4.405.1 Prefinished building materials. Utilize prefinished building materials which do not require additional painting or staining when possible. One or more of the following building materials that do not require additional resources for finishing are used:

    1. Exterior trim not requiring paint or stain.
    2. Windows not requiring paint or stain.
    3. Siding or exterior wall coverings which do not require paint or stain.

    A4.405.2 Concrete floors. Floors that do not require additional coverings are used including but not limited to stained, natural or stamped concrete floors.

    A4.405.3 Recycled content. Comply with the requirements for recycled content in Section A4.405.3.1.

    A4.405.3.1 Recycled content. Use materials, equivalent in performance to virgin materials with a total (combined) recycled content value (RCV) of:

    Tier 1. The RCV shall not be less than 10 percent of the total material cost of the project.

    (Equation A4. 4-1) Required Total RCV (dollars) = Total Material Cost (dollars) × 10 percent

    Tier 2. The RCV shall not be less than 15 percent of the total material cost of the project.

    (Equation A4. 4-2) Required Total RCV (dollars) = Total Material Cost (dollars) × 15 percent

    For the purposes of this section, materials used as components of the structural frame shall not be used to calculate recycled content. The structural frame includes the load bearing structural elements, such as wall studs, plates, sills, columns, beams, girders, joists, rafters and trusses.

    Notes:

    1. Sample forms which allow user input and automatic calculation are located at https://www.hcd.ca.gov/building- standards/calgreen and may be used to simplify documenting compliance with this section and for calculating recycled content value of materials or assembly products.
    2. Sources and recycled content of some recycled materials can be obtained from CalRecycle if not provided by the manufacturer.

    A4.405.3.1.1 Total material cost. Total material cost is the total estimated or actual cost of materials and assembly products used in the project. The required total recycled content value for the project (in dollars) shall be determined by Equation A4.41 or Equation A4.4-2.

    Total material cost shall be calculated by using one of the methods specified below:

    1. Simplified method. To obtain the total cost of the project, multiply the square footage of the residential structure by the square foot valuation established pursuant to the ICC Building Valuation Data (BVD) or other valuation data approved and/or established by the enforcing agency. The total material cost is 45 percent of the total cost of the project. Use Equations A4.4-3A or A4.4-3B to determine total material costs using the simplified method.

    (Equation A4.4-3A) Total material costs = Project square footage × square foot valuation × 45 percent

  • CALGreen § 305.2 High relevance — show source text

    A4.305.2 Recycled water piping. Based on projected availability, dual water piping is installed for future use of recycled water at the following locations:

    1. Interior piping for the use of recycled water is installed to serve all water closets, urinals and floor drains.
    2. Exterior piping is installed to transport recycled water from the point of connection to the structure. Recycled water systems shall be designed and installed in accordance with the California Plumbing Code.

    A4.305.3 Recycled water for landscape irrigation. Recycled water is used for landscape irrigation.

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-13

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    APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

    SECTION A4.306 —INNOVATIVE CONCEPTS AND LOCAL ENVIRONMENTAL CONDITIONS

    A4.306.1 Innovative concepts and local environmental conditions. The provisions of this code are not intended to prevent the use of any alternate material, appliance, installation, device, arrangement, method, design or method of construction not specifically prescribed by this code. This code does not limit the authority of city, county, or city and county government to make necessary changes to the provisions contained in this code pursuant to Section 101.7.1.

    APPENDIX A4-14 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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    A4 RESIDENTIAL VOLUNTARY MEASURES

    DIVISION A4.4 – MATERIAL CONSERVATION AND RESOURCE EFFICIENCY

    SECTION A4.401—GENERAL (RESERVED)

    SECTION A4.402—DEFINITIONS

    A4.402.1 Definitions. The following terms are defined in Chapter 2.

    ASSEMBLY (ASSEMBLY PRODUCT).

    POSTCONSUMER CONTENT.

    PRECONSUMER (OR POSTINDUSTRIAL) CONTENT.

    PROPORTIONAL RECYCLED CONTENT (PRC M ).

    RECYCLED CONTENT (RC).

    RECYCLED CONTENT VALUE (RCV).

    Assembly products (RCV A ). Materials (RCV M ).

    SECTION A4.403—FOUNDATION SYSTEMS

    A4.403.1 Frost protected foundation systems. As allowed by local conditions, utilize a Frost-Protected Shallow Foundation (FPSF) in compliance with the California Residential Code (CRC). When an FPSF foundation system is installed, the manual required by Section 4.410.1 shall include instructions to the owner or occupant regarding the necessity for heating the structure as required in Section R403.3 of the California Residential Code.

    A4.403.2 Reduction in cement use. As allowed by the enforcing agency, cement used in foundation mix design shall be reduced as follows:

    Tier 1. Not less than a 20 percent reduction in cement use.

    Tier 2. Not less than a 25 percent reduction in cement use.

    Note: Products commonly used to replace cement in concrete mix designs include, but are not limited to:

    1. Fly ash.

    2. Slag.

    3. Silica fume.

    4. Rice hull ash.

    SECTION A4.404—EFFICIENT FRAMING TECHNIQUES

  • CALGreen § 405.3.1.2 High relevance — show source text

    A4.405.3.1.2 Determination of total recycled content value (RCV). Total RCV may be determined either by dollars or percentage as noted below.

    1. Total recycled content value for the project (in dollars). This is the sum of the recycled content value of the materials and/or assemblies considered and shall be determined by Equation A4.4-4. The result of this calculation may be directly compared to Equations A4.4-1 and A4.4-2 to determine compliance with Tier 1 or Tier 2 prerequisites.

    (Equation A4.4-4) Total Recycled Content Value (dollars) = (RCV M + RCV A ) 2. Total recycled content value for the project (by percentage). This is expressed as a percentage of the total material cost and shall be determined by Equation A4.4-4 and Equation A4.4-5. The result of this calculation may be directly compared for compliance with Tier 1 (10 percent) or Tier 2 (15 percent) prerequisites.

    (Equation A4.4-5) Total Recycled Content Value (percent) = [Total Recycled Content Value (dollars) ÷ Total Material Cost (dollars)] × 100

    A4.405.3.1.3 Determination of recycled content value of materials (RCV M ). The recycled content value of each material (RCV M ) is calculated by multiplying the cost of material, as defined by the recycled content. See Equations A4.4-6 and A4.4-7.

    (Equation A4.4-6) RCV M (dollars) = Material cost (dollars) × RC M (percent) (Equation A4.4-7) RC M (percent) = Postconsumer content percentage + ( [1] / 2 ) Preconsumer content percentage

    Notes:

    1. If the postconsumer and preconsumer recycled content is provided in pounds, Equation A4.4-7 may be used, but the final result (in pounds) must be multiplied by 100 to show RC M as a percentage.

    APPENDIX A4-16 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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    APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

    1. If the manufacturer reports total recycled content of a material as one percentage in lieu of separately reporting preconsumer and postconsumer values, the total shall be considered preconsumer recycled material.

    A4.405.3.1.4 Determination of recycled content value of assemblies – (RCV A ). Recycled content value of assemblies is calculated by multiplying the total cost of the assembly by the total recycled content of the assembly (RC A ), and shall be determined by Equation A4.4-8.

    (Equation A4.4-8) RCV A (dollars) = Assembly cost (dollars) × Total RC A (percent) If not provided by the manufacturer, Total RC A (percent) is the sum (Σ) of the Proportional Recycled Content (PRC M ) of each material in the assembly. RC A shall be determined by Equation A4.4-9. (Equation A4.4-9) RC A = Σ PRC M

    PRC M of each material may be calculated by one of two methods using the following formulas:

    Method 1: Recycled content (postconsumer and preconsumer) of each material provided in percentages

  • CALGreen § 405.3.1.1 High relevance — show source text

    For the purposes of this section, materials used as components of the structural frame shall not be used to calculate recycled content. The structural frame includes the load bearing structural elements, such as wall studs, plates, sills, columns, beams, girders, joists, rafters and trusses.

    Notes:

    1. Sample forms which allow user input and automatic calculation are located at https://www.hcd.ca.gov/building- standards/calgreen and may be used to simplify documenting compliance with this section and for calculating recycled content value of materials or assembly products.
    2. Sources and recycled content of some recycled materials can be obtained from CalRecycle if not provided by the manufacturer.

    A4.405.3.1.1 Total material cost. Total material cost is the total estimated or actual cost of materials and assembly products used in the project. The required total recycled content value for the project (in dollars) shall be determined by Equation A4.41 or Equation A4.4-2.

    Total material cost shall be calculated by using one of the methods specified below:

    1. Simplified method. To obtain the total cost of the project, multiply the square footage of the residential structure by the square foot valuation established pursuant to the ICC Building Valuation Data (BVD) or other valuation data approved and/or established by the enforcing agency. The total material cost is 45 percent of the total cost of the project. Use Equations A4.4-3A or A4.4-3B to determine total material costs using the simplified method.

    (Equation A4.4-3A) Total material costs = Project square footage × square foot valuation × 45 percent

    (Equation A4.4-3B) Total estimated or actual cost of project × 45 percent 2. Detailed method. To obtain the total cost of the project, add the estimated and/or actual costs of materials used for the project, including the structure (steel, concrete, wood or masonry); the enclosure (roof, windows, doors and exterior walls); the interior walls, ceilings and finishes (gypsum board, ceiling tiles, etc.). The total estimated and/or actual costs shall not include fees, labor and installation costs, overhead, appliances, equipment, furniture or furnishings.

    A4.405.3.1.2 Determination of total recycled content value (RCV). Total RCV may be determined either by dollars or percentage as noted below.

    1. Total recycled content value for the project (in dollars). This is the sum of the recycled content value of the materials and/or assemblies considered and shall be determined by Equation A4.4-4. The result of this calculation may be directly compared to Equations A4.4-1 and A4.4-2 to determine compliance with Tier 1 or Tier 2 prerequisites.

    (Equation A4.4-4) Total Recycled Content Value (dollars) = (RCV M + RCV A ) 2. Total recycled content value for the project (by percentage). This is expressed as a percentage of the total material cost and shall be determined by Equation A4.4-4 and Equation A4.4-5. The result of this calculation may be directly compared for compliance with Tier 1 (10 percent) or Tier 2 (15 percent) prerequisites.

    (Equation A4.4-5) Total Recycled Content Value (percent) = [Total Recycled Content Value (dollars) ÷ Total Material Cost (dollars)] × 100

  • CALGreen § 601.5.2 High relevance — show source text

    A4.601.5.2 Prerequisite and elective measures for Tier 2. In addition to the mandatory measures, compliance with the following prerequisite and elective measures from Appendix A4 is also required to achieve Tier 2 status.

    1. From Division A4.1, Planning and Design.

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-21

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

    APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

    1.1. Comply with the topsoil protection requirements for Tier 1 and Tier 2 in Section A4.106.2.3. 1.2. Comply with the 30 percent permeable paving requirements in Section A4.106.4. 1.3. Comply with the cool roof requirements in Section A4.106.5. 1.4. Comply with the Tier 2 electric vehicle (EV) charging requirements in Section A4.106.8. 1.5. Comply with at least four elective measures selected from Division A4.1. 2. From Division A4.2, Energy Efficiency. 2.1. For newly constructed low-rise residential buildings, comply with the energy efficiency requirements in Sections A4.203.1, A4.203.1.1, Table A4.203.1.1, A4.203.1.2 and A4.203.1.3.

    1. From Division A4.3, Water Efficiency and Conservation. 3.1. Comply with at least three elective measures selected from Division A4.3.
    2. From Division A4.4, Material Conservation and Resource Efficiency. 4.1. Comply with the 25 percent cement reduction requirements in Section A4.403.2. 4.2. Comply with the 15 percent recycled content requirements in Section A4.405.3.1. 4.3. Comply with the 75 percent reduction in construction waste in Section A4.408.1. 4.4. Comply with at least four elective measures selected from Division A4.4.
    3. From Division A4.5, Environmental Quality. 5.1. Comply with the 100 percent resilient flooring systems requirements in Section A4.504.2. 5.2. Comply with the thermal insulation requirements for Tier 1 and Tier 2 in Section A4.504.3. 5.3. Comply with at least one elective measure selected from Division A4.5.

    Note: The Residential Occupancies Application Checklist contained in Section A4.602 may be used to show which elective measures are selected.

    APPENDIX A4-22 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

    DIVISION A4.6 – TIER 1 AND TIER 2

    SECTION A4.602 — RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST

  • CALGreen § 404.1 High relevance — show source text

    A4.404.1 Lumber size. Beams, headers and trimmers are sized and installed as specified in Chapter 23 of the California Building Code, or Chapter 6 of the California Residential Code, as applicable. Other calculations acceptable to the enforcing agency which use the minimum size member for the tributary load shall be acceptable.

    A4.404.2 Dimensions and layouts. Building dimensions and layouts are designed to minimize waste by one or more of the following measures in at least 80 percent of the structure:

    1. Building design dimensions in 2-foot increments are used.
    2. Windows and doors are located at regular 16 ″ or 24 ″ stud positions.
    3. Other methods acceptable to the enforcing agency.

    A4.404.3 Building systems. Use premanufactured building systems to eliminate solid sawn lumber whenever possible. One or more of the following premanufactured building systems is used:

    1. Composite floor joist or premanufactured floor framing system.
    2. Composite roof rafters or premanufactured roof framing system.
    3. Panelized (SIPS, ICF or similar) framing systems.
    4. Other methods approved by the enforcing agency.

    A4.404.4 Pre-cut materials and details. Material lists are included in the plans which specify the material quantity and provide direction for on-site cuts to be made from the material provided. Material lists and direction shall be provided for the following systems:

    1. Floor framing.
    2. Wall framing.
    3. Ceiling and roof framing.
    4. Structural panels and roof sheathing.

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-15

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

    APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

    SECTION A4.405—MATERIAL SOURCES

    A4.405.1 Prefinished building materials. Utilize prefinished building materials which do not require additional painting or staining when possible. One or more of the following building materials that do not require additional resources for finishing are used:

    1. Exterior trim not requiring paint or stain.
    2. Windows not requiring paint or stain.
    3. Siding or exterior wall coverings which do not require paint or stain.

    A4.405.2 Concrete floors. Floors that do not require additional coverings are used including but not limited to stained, natural or stamped concrete floors.

    A4.405.3 Recycled content. Comply with the requirements for recycled content in Section A4.405.3.1.

    A4.405.3.1 Recycled content. Use materials, equivalent in performance to virgin materials with a total (combined) recycled content value (RCV) of:

    Tier 1. The RCV shall not be less than 10 percent of the total material cost of the project.

    (Equation A4. 4-1) Required Total RCV (dollars) = Total Material Cost (dollars) × 10 percent

    Tier 2. The RCV shall not be less than 15 percent of the total material cost of the project.

    (Equation A4. 4-2) Required Total RCV (dollars) = Total Material Cost (dollars) × 15 percent

    For the purposes of this section, materials used as components of the structural frame shall not be used to calculate recycled content. The structural frame includes the load bearing structural elements, such as wall studs, plates, sills, columns, beams, girders, joists, rafters and trusses.

    Notes:

  • CALGreen § 305.1 High relevance — show source text

    305.1**Piping is installed to permit future use of a graywater
    irrigation system served by the clothes washer or other fixtures.||
    |
    |
    |
    |
    | |A4.305.2 Recycled water piping is installed.||
    |
    |
    |
    |
    | |A4.305.3Recycled water is used for landscape irrigation.||||||| |Innovative Concepts and Local Environmental Conditions||||||| |A4.306.1Items in this section are necessary to address innovative
    concepts or local environmental conditions.||||||| |Item 1|
    |
    |
    |
    |
    |
    | |Item 2|
    |
    |
    |
    |
    |
    | |Item 3|||||||

    APPENDIX A4-26 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

    APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

    SECTION A4.602—RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST—continued

    FEATURE OR MEASURE LEVELS
    APPLICANT TO SELECT ELECTIVE MEASURES    		 Col3 Col4 VERIFICATIONS
    ENFORCING AGENCY TO SPECIFY
    VERIFICATION METHOD    		 Col6 Col7
    FEATURE OR MEASURE Mandatory Prerequisites and electives1 Prerequisites and electives1 Enforcing
    Agency

    All    		 Installer or
    Designer

    All    		 Third
    party

    All
    FEATURE OR MEASURE Mandatory Tier 1 Tier 2 Tier 2 Tier 2 Tier 2
    MATERIAL CONSERVATION AND RESOURCE EFFICIENCY
    Foundation Systems
    A4.403.1A Frost-protected Shallow Foundation (FPSF) is designed
    and constructed.
    A4.403.2Cement use in foundation mix design is reduced.
    Tier 1. Not less than a 20 percent reduction in cement use.
    **Tier 2.

Frequently asked questions

Can I count structural framing materials toward the RCV target?

No. Materials used as components of the structural frame are explicitly excluded from the RCV calculation in § A4.405.3.1.

If I use fly ash or slag in concrete, how do I show compliance for cement reduction?

Design the foundation mix so cement content is reduced at least 20% (Tier 1) or 25% (Tier 2) compared to your baseline mix and document the mix design and supplier data. See § A4.403.2.

When using SCMs, do I calculate recycled content on the entire concrete cost?

No. § A4.405.3.1.5 permits calculating recycled content for concrete by applying the recycled-content percent to the cost of cementitious materials only, not the total concrete cost.

Which method should I use to determine total material cost?

You may use the simplified method (sq ft × valuation × 45%) or the detailed method (sum of material costs); both are allowed in § A4.405.3.1.1. Choose the one acceptable to your enforcing agency.

Do Tier thresholds apply automatically statewide?

Tier measures are in Appendix A4 (voluntary) and can be adopted/required by local jurisdictions; cement reduction is to be implemented “as allowed by the enforcing agency,” so check local adoption/enforcement rules. § A4.403.2 and Appendix A4 notes.

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Indoor fixture requirements, submeters and outdoor potable‑water measures

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Divisions A4.3 & A4.4 — Water Efficiency, Material Conservation & Waste

California Green Building Standards Code (CALGreen)