Title 24 · California Energy Code

Residential continuous insulation tables and limits (R702.7(4) and R702.7(5))

If you add foam or other continuous insulation on the outside of framed walls to control moisture, California’s residential code sets minimum exterior R‑values that depend on climate zone and whether you have an interior vapor retarder. Use **§ R702.7(4)** when you have a Class I/II responsive interior vapor retarder and **§ R702.7(5)** when you do not; note § R702.7(5) also limits interior insulation to R‑5 and requires an exterior low‑permeance layer (or CI that itself is Class I/II).

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Last reviewed: July 6, 2026

What the code requires — plain English

  • Where you place foam/plastic continuous insulation on exterior framed walls to control moisture, the California Residential Code sets minimum continuous insulation R-values based on climate zone and on whether there is an interior vapor retarder. See § R702.7(4) for walls with a Class I or II responsive interior vapor retarder and § R702.7(5) for walls without a Class I, II or III interior vapor retarder.
  • These tables are moisture-control limits (to permit specific vapor-retarder strategies); they do not replace the energy-code insulation requirements of Chapter 11 (the California Energy Code).

The single most important rule: use the table that matches whether you have an interior vapor retarder — if you don’t, the required exterior continuous insulation R-value is higher and additional limits apply to interior insulation.

Requirements in detail

Definitions and bold key terms on first use:

  • Continuous insulation (CI) — insulation applied continuously over the exterior side of the wall framing (e.g., foam sheathing or insulated siding).
  • Responsive vapor retarder — a vapor retarder that permits drying under typical hygrothermal conditions when placed on the interior face; permitted interiorly in many zones per the code.

Table summary — walls with a Class I or II responsive interior vapor retarder (use § R702.7(4))

Climate zone Required continuous insulation (CI) Code Reference
3 CI R ≥ 2 § R702.7(4)
4, 5, 6 CI R ≥ 3 over 2×4 wall; CI R ≥ 5 over 2×6 wall § R702.7(4)
7 CI R ≥ 5 over 2×4 wall; CI R ≥ 7.5 over 2×6 wall § R702.7(4)
8 CI R ≥ 7.5 over 2×4 wall; CI R ≥ 10 over 2×6 wall § R702.7(4)

Notes: these requirements in § R702.7(4) apply when continuous insulation is used specifically to control moisture to permit the use of a Class I or II vapor retarder. They also “contribute to but do not supersede” Chapter 11 energy requirements.

Table summary — walls without a Class I, II or III interior vapor retarder (use § R702.7(5))

Climate zone Required continuous insulation (CI) Additional limits / conditions Code Reference
4 CI R ≥ 4.5 Interior total insulation to the interior side of the CI must not exceed R‑5 (see note). Exterior-side water‑vapor control (≤1 perm, dry cup) is required adjacent to the CI. § R702.7(5)
5 CI R ≥ 6.5 Same limits as above § R702.7(5)
6 CI R ≥ 8.5 Same limits as above § R702.7(5)
7 CI R ≥ 11.5 Same limits as above § R702.7(5)
8 CI R ≥ 14 Same limits as above § R702.7(5)

Key textual requirements that accompany Table R702.7(5):

  • Interior insulating value limit: “The total insulating value of materials to the interior side of the exterior continuous insulation, including any cavity insulation, shall not exceed R‑5. Where the R‑value of materials to the interior side of the exterior continuous insulation exceeds R‑5, an approved design shall be required.” § R702.7(5).
  • Exterior vapor-control requirement: a water‑vapor control layer with permeance ≤ 1 perm (ASTM E96 Procedure A, dry cup) must be placed on the exterior side of the wall and to the interior side of the exterior continuous insulation; the exterior CI itself is allowed to serve as that vapor control layer if the CI (at installed thickness or with an interior facer) is a Class I or II vapor retarder. § R702.7(5).

Spray foam equivalence and installation rules

  • For the tables in R702.7, certain spray foam applications are treated as meeting the continuous‑insulation moisture‑control requirement where spray foam (installed on the interior side of sheathing or gypsum) has maximum permeance of 1.5 perms at the installed thickness and either: (1) the spray foam R‑value meets or exceeds the table R‑value, or (2) the combined R‑value of spray foam plus exterior CI equals or exceeds the table R‑value. See § R702.7.1.
  • Vapor retarder installation must follow manufacturer instructions or approved design; when it also functions as an air barrier, install per the Energy Code air‑barrier requirements. See § R702.7.2.

Exceptions & special cases

  • Use of a responsive Class I or II interior vapor retarder is specifically called out and allowed; use of a non‑responsive Class I interior vapor retarder opposite an exterior Class I retarder requires an approved design. See accompanying notes to the tables and § R702.7 commentary.
  • If the interior‑side total insulation (cavity + interior finish insulation) exceeds R‑5 for a wall governed by § R702.7(5), you must have an approved design showing hygrothermal safety — the prescriptive table limit is not met.
  • Where exterior CI is meant to serve as the vapor control layer, it must be a Class I or II vapor retarder at its installed thickness or with an interior facer. Otherwise add the separate exterior low‑permeance layer (≤1 perm).
  • These R702.7 moisture‑control tables are separate from (and do not relieve) the assembly U‑factor or total thermal requirements in the California Energy Code (Chapter 11 / § 150.1). Always confirm thermal compliance to the Energy Code as well.

Common mistakes

  • Assuming the tables are energy‑code minimums — they are moisture‑control prescriptions and “contribute to but do not supersede” energy‑code requirements. Check Chapter 11 separately.
  • Exceeding interior-side R‑5 while relying on § R702.7(5) without obtaining an approved design. The table explicitly limits interior insulation to R‑5 in that case.
  • Using a Class I interior retarder that is not responsive when there is also a Class I exterior retarder — this combination requires an approved design. (Responsive vs non‑responsive matters.)
  • Forgetting the required ≤1 perm exterior water‑vapor control when there is no interior vapor retarder per § R702.7(5), or failing to document that the CI itself is a Class I/II retarder at installed thickness.

Worked example — concrete scenario

Scenario: New wood‑frame home in Climate Zone 7, exterior framed walls built with 2×6 studs, and no interior vapor retarder is installed.

  1. Which table applies? — Walls without a Class I, II or III interior vapor retarder → use § R702.7(5).
  2. Required CI R‑value from the table: CI R ≥ 11.5 for Climate Zone 7 (2×6 wall). § R702.7(5).
  3. Additional mandatory limits: the total insulating value to the interior side of the CI (including cavity insulation) must not exceed R‑5 unless you provide an approved design; and you must provide a vapor control layer on the exterior side with permeance ≤ 1 perm or have the CI itself be a Class I/II vapor retarder at installed thickness. § R702.7(5).
  4. Illustrative thickness calculation (example only): if you choose polyiso board typically rated near R‑6 per inch (manufacturer data required for actual product), you would need about 11.5 ÷ 6 ≈ 1.9 inches → round up to a commercially available 2‑inch polyiso board to meet CI R≥11.5. Note: this material R‑per‑inch is illustrative — verify the product’s published R‑value and confirm vapor‑retarder classification by manufacturer documentation. (Code does not mandate a material; it mandates the R‑value and vapor‑retarder behavior.)

Related provisions

  • § R702.7.1 — Spray foam rules for meeting CI moisture‑control R‑value (permeance ≤1.5 perms equivalence / combined R‑value).
  • § R702.7.2 — Vapor retarder installation and air‑barrier interaction (follow manufacturer / approved design).
  • § R702.7.3 — Climate‑zone mapping and cross‑reference to IECC/CEC climate zones for these rules.
  • Table R702.7(3) — Class III vapor retarder allowances and related CI thresholds in some zones (useful when considering Class III strategies).
  • California Energy Code § 150.1 / Table 150.1‑A — overall assembly U‑factor / thermal compliance requirements (CI choices also affect energy compliance).

Code references

Grounded in the retrieved California Energy Code — click a citation to read the verbatim passage:

  • § 7-8 High relevance — show source text

    The insulation materials used to satisfy
    this option also contribute to but do not supersede the thermal envelope requirements of Chapter 11.|

    7-8 2025 CALIFORNIA RESIDENTIAL CODE

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

    WALL COVERING

    TABLE R702.7(4)—CONTINUOUS INSULATION WITH CLASS I OR II RESPONSIVE VAPOR RETARDER Col2
    CLIMATE ZONE PERMITTED CONDITIONSa
    3 Continuous insulation with_R_-value ≥ 2.
    4, 5 and 6 Continuous insulation with_R_-value ≥ 3 over 2 × 4 wall.
    Continuous insulation with_R_-value ≥ 5 over 2 × 6 wall.
    7 Continuous insulation with_R_-value ≥ 5 over 2 × 4 wall.
    Continuous insulation with_R_-value ≥ 7.5 over 2 × 6 wall.
    8 Continuous insulation with_R_-value ≥ 7.5 over 2 × 4 wall.
    Continuous insulation with_R_-value ≥ 10 over 2 × 6 wall.
    a. The requirements in this table apply only to insulation used to control moisture in order to permit the use of Class II vapor retarders. The insulation materials used to satisfy
    this option also contribute to but do not supersede the thermal envelope requirements of Chapter 11.    		 a. The requirements in this table apply only to insulation used to control moisture in order to permit the use of Class II vapor retarders. The insulation materials used to satisfy
    this option also contribute to but do not supersede the thermal envelope requirements of Chapter 11.
    TABLE R702.7(5)—CONTINUOUS INSULATION ON WALLS WITHOUT A CLASS I, II OR III INTERIOR VAPOR RETARDERa Col2
    CLIMATE ZONE PERMITTED CONDITIONSb, c
    4 Continuous insulation with_R_-value ≥ 4.5
    5 Continuous insulation with_R_-value ≥ 6.5
    6 Continuous insulation with_R_-value ≥ 8.5
    7 Continuous insulation with_R_-value ≥ 11.5
    8 Continuous insulation with_R_-value ≥ 14
    a. The total insulating value of materials to the interior side of the exterior continuous insulation, including any cavity insulation, shall not exceed R-5. Where the R-value of
    materials to the interior side of the exterior continuous insulation exceeds R-5, an approved design shall be required.
    b. A water vapor control material layer having a permeance not greater than 1 perm in accordance with ASTM E96 Procedure A (dry cup) shall be placed on the exterior side of
    the wall and to the interior side of the exterior continuous insulation. The exterior continuous insulation shall be permitted to serve as the vapor control layer where, at its
    installed thickness or with a facer on its interior face, the exterior continuous insulation is a Class I or II vapor retarder.
    c. The requirements in this table apply only to insulation used to control moisture in order to allow walls without a Class I, II or III interior vapor retarder. The insulation materi-
    als used to satisfy this option also contribute to but do not supersede the thermal envelope requirements of the_California Energy Code_.    		 a. The total insulating value of materials to the interior side of the exterior continuous insulation, including any cavity insulation, shall not exceed R-5.
  • § 2.5 High relevance — show source text

    Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder_.|a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder    .|a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder    ._|

    TABLE R702.7(3)—CLASS III VAPOR RETARDERS Col2
    ** CLIMATE ZONE** ** CLASS III VAPOR RETARDERS PERMITTED FOR:a, b**
    Marine 4 Vented cladding over wood structural panels.
    Marine 4 Vented cladding over fiberboard.
    Marine 4 Vented cladding over gypsum.
    Marine 4 Continuous insulation with_R_-value ≥ 2.5 over 2 × 4 wall.
    Marine 4 Continuous insulation with_R_-value ≥ 3.75 over 2 × 6 wall.
    5 Vented cladding over wood structural panels.
    5 Vented cladding over fiberboard.
    5 Vented cladding over gypsum.
    5 Continuous insulation with_R_-value ≥ 5 over 2 × 4 wall.
    5 Continuous insulation with_R_-value ≥ 7.5 over 2 × 6 wall.
    6 Vented cladding over fiberboard.
    6 Vented cladding over gypsum.
    6 Continuous insulation with_R_-value ≥ 7.5 over 2 × 4 wall.
    6 Continuous insulation with_R_-value ≥ 11.25 over 2 × 6 wall.
    7 Continuous insulation with_R_-value ≥ 10 over 2 × 4 wall.
    7 Continuous insulation with_R_-value ≥ 15 over 2 × 6 wall.
    8 Continuous insulation with_R_-value ≥ 12.5 over 2 × 4 wall.
    Continuous insulation with_R_-value ≥ 20 over 2 × 6 wall.
    a.
  • § 1404.3.1 High relevance — show source text

    The exterior continuous insulation shall be permitted to serve as the vapor control layer where, at its
    installed thickness or with a facer on its interior face, the exterior continuous insulation is a Class I or II vapor retarder.
    c. The requirements of this table apply only to continuous insulation used to control moisture in order to allow walls without a Class I, II or III interior vapor retarder. The insula-
    tion materials used to satisfy this option also contribute to but do not supersede the_building_ thermal envelope requirements of the_California Energy Code_.|a. The total insulating value of materials to the interior side of the exterior continuous insulation, including any cavity insulation, shall not exceed R-5. Where the_R_-value of
    materials to the interior side of the exterior continuous insulation exceeds R-5, an_approved_ design shall be required.
    b. A water vapor control material layer having a permeance of not greater than 1 perm in accordance with ASTM E96, Procedure A (dry cup) shall be placed on the exterior side
    of the wall and to the interior side of the exterior continuous insulation. The exterior continuous insulation shall be permitted to serve as the vapor control layer where, at its
    installed thickness or with a facer on its interior face, the exterior continuous insulation is a Class I or II vapor retarder.
    c. The requirements of this table apply only to continuous insulation used to control moisture in order to allow walls without a Class I, II or III interior vapor retarder. The insula-
    tion materials used to satisfy this option also contribute to but do not supersede the_building_ thermal envelope requirements of the_California Energy Code_.|

    �

    EXTERIOR WALLS

    1404.3.1 Spray foam plastic insulation for moisture control with Class II and III vapor retarders. For purposes of compliance with Tables 1404.3(3) and 1404.3(4), spray foam with a maximum permeance of 1.5 perms at the installed thickness applied to the interior side of wood structural panels, fiberboard, insulating sheathing or gypsum shall be deemed to meet the continuous insulation moisture control requirement in accordance with one of the following conditions:

    1. The spray foam R -value meets or exceeds the specified continuous insulation R-value.
    2. The combined R -value of the spray foam and continuous insulation is equal to or greater than the specified continuous insulation R -value.

    1404.3.2 Vapor retarder installation. Vapor retarders shall be installed in accordance with the manufacturer’s instructions or an approved design. Where a vapor retarder also functions as a component of a continuous air barrier, the vapor retarder shall be installed as an air barrier in accordance with the California Energy Code . 1404.3.3 California Energy Code and International Energy Conservation Code Climate Zones. The IECC climate zones used by this section differ from those used by the California Energy Code to determine applicability of energy efficiency measures. Comparison of IECC and California Energy Code climate zones is shown in Chapter 12, Table 1202.3.1. 1404.4 Flashing. Flashing shall be installed in such a manner so as to prevent moisture from entering the exterior wall or to redirect that moisture to the surface of the exterior wall covering or to a water-resistive barrier complying with Section 1403.2 and that is part of a means of drainage complying with Section 1402.2.

  • California Energy Code High relevance — show source text
    TABLE R702.7(2)—VAPOR RETARDER OPTIONS Col2 Col3 Col4
    CLIMATE ZONE VAPOR RETARDER CLASS VAPOR RETARDER CLASS VAPOR RETARDER CLASS
    CLIMATE ZONE CLASS Ia CLASS IIa CLASS III
    1, 2 Not Permitted Not Permitted Permitted
    3, 4 (except Marine 4) Not Permitted Permittedc Permitted
    Marine 4, 5, 6, 7, 8 Permittedb, c Permittedc See Table R702.7(3)
    a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder_._    		 a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder_._    		 a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder_._    		 a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder_._

    |TABLE R702.

  • § 7.1 High relevance — show source text

    The total insulating value of materials to the interior side of the exterior continuous insulation, including any cavity insulation, shall not exceed R-5. Where the R-value of
    materials to the interior side of the exterior continuous insulation exceeds R-5, an approved design shall be required.
    b. A water vapor control material layer having a permeance not greater than 1 perm in accordance with ASTM E96 Procedure A (dry cup) shall be placed on the exterior side of
    the wall and to the interior side of the exterior continuous insulation. The exterior continuous insulation shall be permitted to serve as the vapor control layer where, at its
    installed thickness or with a facer on its interior face, the exterior continuous insulation is a Class I or II vapor retarder.
    c. The requirements in this table apply only to insulation used to control moisture in order to allow walls without a Class I, II or III interior vapor retarder. The insulation materi-
    als used to satisfy this option also contribute to but do not supersede the thermal envelope requirements of the_California Energy Code_.|a. The total insulating value of materials to the interior side of the exterior continuous insulation, including any cavity insulation, shall not exceed R-5. Where the R-value of
    materials to the interior side of the exterior continuous insulation exceeds R-5, an approved design shall be required.
    b. A water vapor control material layer having a permeance not greater than 1 perm in accordance with ASTM E96 Procedure A (dry cup) shall be placed on the exterior side of
    the wall and to the interior side of the exterior continuous insulation. The exterior continuous insulation shall be permitted to serve as the vapor control layer where, at its
    installed thickness or with a facer on its interior face, the exterior continuous insulation is a Class I or II vapor retarder.
    c. The requirements in this table apply only to insulation used to control moisture in order to allow walls without a Class I, II or III interior vapor retarder. The insulation materi-
    als used to satisfy this option also contribute to but do not supersede the thermal envelope requirements of the_California Energy Code_.|

    R702.7.1 Spray foam plastic insulation for moisture control with Class II and III vapor retarders. For purposes of compliance with Tables R702.7(3) and R702.7(4), spray foam with a maximum permeance of 1.5 perms at the installed thickness applied to the interior side of wood structural panels, fiberboard, insulating sheathing or gypsum shall be deemed to meet the continuous insulation moisture control requirement in accordance with one of the following conditions:

    1. The spray foam R -value is equal to or greater than the specified continuous insulation R -value.
    2. The combined R -value of the spray foam and continuous insulation is equal to or greater than the specified continuous insulation R -value.

    R702.7.2 Vapor retarder installation. Vapor retarders shall be installed in accordance with the manufacturer’s instructions, accepted installation methods or an approved design. Where a vapor retarder also functions as a component of a continuous air barrier, the vapor retarder shall be installed as an air barrier in accordance with Section N1102.5.1.1.

    R702.7.3 California Energy Code and International Energy Conservation Code Climate Zones. The IECC climate zones used by this section differ from those used by the California Energy Code to determine applicability of energy efficiency measures. Comparison of IECC and California Energy Code climate zones is shown in Table R702.7.3.

    |TABLE R702.7.3—IECC VS.

  • § 17.44 High relevance — show source text

    85| |60|30|7:12|17.44|18.99|22.29|25.85|29.67|33.76|12.54| |60|30|12:12|24.62|26.81|31.46|36.49|41.89|47.66|14.48| |60|45|< 1:12|10.27|11.18|13.12|15.21|17.47|19.87|10.50| |60|45|5:12|14.26|15.52|18.22|21.13|24.26|27.60|12.82| |60|45|7:12|20.21|22.01|25.83|29.95|34.39|39.12|13.86| |60|45|12:12|31.20|33.97|39.87|46.23|53.07|60.39|16.76| |60|60|< 1:12|10.64|11.59|13.60|15.77|18.11|20.60|10.70| |60|60|5:12|14.77|16.09|18.88|21.90|25.14|28.60|13.79| |60|60|7:12|23.05|25.09|29.45|34.15|39.21|44.61|15.18| |60|60|12:12|37.97|41.34|48.52|56.27|64.60|73.49|19.05| |For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 pound force per linear foot = 0.146 kN/m, 1 pound per square foot = 47.88 Pa.
    a. Tabulated lengths were derived by calculating design wind pressures in accordance with Figure 28.4-1 of ASCE 7 for a building with a mean roof height of 35 feet, topographic
    factor,Kzt, equal to 1.0, and Risk Category II. For wind perpendicular to the ridge, the effects of a 2-foot overhang on each endwall are included. The design pressures were
    used to calculate forces to be resisted by solid wall segments in each endwall. The forces to be resisted by each wall line were then divided by the default design strength of
    840 pounds per linear foot of length to determine the unreduced length,UR, of solid wall length required in each endwall. The actual mean roof height of the building shall
    not exceed the least horizontal dimension of the building.
    b. Tabulated lengths in the “minimum” column are based on the requirement of Section 28.4.4 of ASCE 7 that the main windforce-resisting system be designed for a minimum
    pressure of 1016 psf multiplied by the wall area of the building and 8 psf multiplied by the roof area of the building projected onto a vertical plane normal to the assumed
    wind direction. Tabulated lengths in shaded cells are less than the “minimum” value. Where the minimum controls, it is permitted to be reduced in accordance with Notes c,
    d and e. See Section R608.7.1.1.
    c.

  • § 1404.3 High relevance — show source text

    The requirements in this table apply only to insulation used to control moisture in order to permit the use of Class I or II vapor retarders. The insulation materials used to
    satisfy this option also contribute to but do not supersede the building thermal envelope requirements of the_California Energy Code_.|

    TABLE 1404.3(5)—CONTINUOUS INSULATION ON WALLS WITHOUT A CLASS I, II, OR III INTERIOR VAPOR RETARDERa Col2
    CLIMATE ZONE PERMITTED CONDITIONSb,c
    4 Continuous insulation with_R_-value ≥ 4.5
    5 Continuous insulation with_R_-value ≥ 6.5
    6 Continuous insulation with_R_-value ≥ 8.5
    7 Continuous insulation with_R_-value ≥ 11.5
    8 Continuous insulation with_R_-value ≥ 14
    a. The total insulating value of materials to the interior side of the exterior continuous insulation, including any cavity insulation, shall not exceed R-5. Where the_R_-value of
    materials to the interior side of the exterior continuous insulation exceeds R-5, an_approved_ design shall be required.
    b. A water vapor control material layer having a permeance of not greater than 1 perm in accordance with ASTM E96, Procedure A (dry cup) shall be placed on the exterior side
    of the wall and to the interior side of the exterior continuous insulation. The exterior continuous insulation shall be permitted to serve as the vapor control layer where, at its
    installed thickness or with a facer on its interior face, the exterior continuous insulation is a Class I or II vapor retarder.
    c. The requirements of this table apply only to continuous insulation used to control moisture in order to allow walls without a Class I, II or III interior vapor retarder. The insula-
    tion materials used to satisfy this option also contribute to but do not supersede the_building_ thermal envelope requirements of the_California Energy Code_.    		 a. The total insulating value of materials to the interior side of the exterior continuous insulation, including any cavity insulation, shall not exceed R-5. Where the_R_-value of
    materials to the interior side of the exterior continuous insulation exceeds R-5, an_approved_ design shall be required.
    b. A water vapor control material layer having a permeance of not greater than 1 perm in accordance with ASTM E96, Procedure A (dry cup) shall be placed on the exterior side
    of the wall and to the interior side of the exterior continuous insulation. The exterior continuous insulation shall be permitted to serve as the vapor control layer where, at its
    installed thickness or with a facer on its interior face, the exterior continuous insulation is a Class I or II vapor retarder.
    c. The requirements of this table apply only to continuous insulation used to control moisture in order to allow walls without a Class I, II or III interior vapor retarder. The insula-
    tion materials used to satisfy this option also contribute to but do not supersede the_building_ thermal envelope requirements of the_California Energy Code_.

    �

    EXTERIOR WALLS

  • § 2.3.1 High relevance — show source text

    2025 CALIFORNIA RESIDENTIAL CODE APPENDIX CK-7

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

    APPENDIX CK-8 2025 CALIFORNIA RESIDENTIAL CODE

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

    2025 CALIFORNIA RESIDENTIAL CODE APPENDIX NA-1

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

    APPENDIX NA-2 2025 CALIFORNIA RESIDENTIAL CODE

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

    Concrete Capillary break R506.2.3.1 Compressive strength R402.2 Floors (on ground) R506 Tile (roof) R905.3 Weathering Figure R301.2(1), R402.2 Construction

    3D-printed Appendix BM Cavity wall masonry R608 Cob Appendix BK Extended plate walls Appendix BN Flood-resistant R306

    Floors Chapter 5 Footings R403 Foundation material R402

    Foundation walls R404

    Foundations Chapter 4 Hemp-lime Appendix BL Masonry R606, R607, R608, R610 Pollutant control R340 Roofs Chapter 8 Steel framing R505, R603, R804 Strawbale Appendix BJ Straw-clay Appendix BI Walls Chapter 6 Waste R334.1 Wood framing R502, R602, R802 Construction Documents R106, R306.3.9

    Court Emergency escape and rescue openings R319.1, R319.2.4 Means of egress R318.1 Natural light R325.1.1 Covering Exterior R703

    Interior R702 Roof Chapter 9 Wall Chapter 7 Crawl Space R408

    Access R408.4

    Damper Fireplace R1001.7.1 Dampproofing R406 Day Care Appendix BD Defined R202 Large family day-care homes R336 Dead Loads R301.4

    Decay Protection against R304 Deck

    Attachment R318.5 Supported by exterior wall R507 Wood/plastic composite boards R507.2.2

    Definitions Building R202 Mechanical system R202 Plumbing R202 Design Criteria R301 Alternative provisions R301.1.1 Application R301.1 Climatic and geographic R301.2 Dead load R301.4

    Deflection R301.6 Engineered design R301.1.3

    Accessibility R322 Accessory Dwelling Unit R202 Authority to Enforce Automatic Fire Sprinkler Systems 1.8.9.1, R313.2 Accessory Structure Elevations R306.3.2

    Energy R330.5 Exterior walls R302.1

    Scope R101.2 Addition (see also Existing Buildings) Carbon monoxide alarms R311.2.2 Change of occupancy R110.1 Construction R302.2.3

  • § 14-7 High relevance — show source text

    Vented cladding shall include vinyl lap siding, polypropylene, horizontal aluminum siding, brick veneer with airspace as specified in this code, rainscreen systems and other
    approved vented claddings.
    b. The requirements in this table apply only to insulation used to control moisture in order to permit the use of Class III vapor retarders. The insulation materials used to satisfy
    this option also contribute to but do not supersede the building thermal envelope requirements of the_California Energy Code_.|

    2025 CALIFORNIA BUILDING CODE 14-7

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

    TABLE 1404.3(4)—CONTINUOUS INSULATION WITH A CLASS I OR II RESPONSIVE VAPOR RETARDER Col2
    CLIMATE ZONE PERMITTED CONDITIONSa
    3 Continuous insulation with_R_-value ≥ R-2
    4, 5, 6 Continuous insulation with_R_-value ≥ R-3 over 2 × 4 wall
    Continuous insulation with_R_-value ≥ R-5 over 2 × 6 wall
    7 Continuous insulation with_R_-value ≥ R-5 over 2 × 4 wall
    Continuous insulation with_R_-value ≥ R-7.5 over 2 × 6 wall
    8 Continuous insulation with_R_-value ≥ R-7.5 over 2 × 4 wall
    Continuous insulation with_R_-value ≥ R-10 over 2 × 6 wall
    a. The requirements in this table apply only to insulation used to control moisture in order to permit the use of Class I or II vapor retarders. The insulation materials used to
    satisfy this option also contribute to but do not supersede the building thermal envelope requirements of the_California Energy Code_.    		 a. The requirements in this table apply only to insulation used to control moisture in order to permit the use of Class I or II vapor retarders. The insulation materials used to
    satisfy this option also contribute to but do not supersede the building thermal envelope requirements of the_California Energy Code_.
    TABLE 1404.3(5)—CONTINUOUS INSULATION ON WALLS WITHOUT A CLASS I, II, OR III INTERIOR VAPOR RETARDERa Col2
    CLIMATE ZONE PERMITTED CONDITIONSb,c
    4 Continuous insulation with_R_-value ≥ 4.5
    5 Continuous insulation with_R_-value ≥ 6.5
    6 Continuous insulation with_R_-value ≥ 8.5
    7 Continuous insulation with_R_-value ≥ 11.5
    8 Continuous insulation with_R_-value ≥ 14
    a. The total insulating value of materials to the interior side of the exterior continuous insulation, including any cavity insulation, shall not exceed R-5. Where the_R_-value of
    materials to the interior side of the exterior continuous insulation exceeds R-5, an_approved_ design shall be required.
    b. A water vapor control material layer having a permeance of not greater than 1 perm in accordance with ASTM E96, Procedure A (dry cup) shall be placed on the exterior side
    of the wall and to the interior side of the exterior continuous insulation. The exterior continuous insulation shall be permitted to serve as the vapor control layer where, at its
    installed thickness or with a facer on its interior face, the exterior continuous insulation is a Class I or II vapor retarder.
    c.
  • § 1.5 High relevance — show source text

    Below grade “interior” denotes insulation installed on the inside surface of the wall, and below grade “exterior” denotes insulation installed on the outside surface of the wall.
    8. HSPF2 means heating seasonal performance factor.
    9. When whole-house fans are required (REQ), only those whole-house fans that are listed in the Home Ventilating Institute Certified Products Directory may be installed.
    Compliance requires installation of one or more WHFs whose total airflow cfm is capable of meeting or exceeding a minimum 1.5 cfm/square foot of conditioned floor area as
    specified by Section 150.1(c)12.
    10. A supplemental heating unit may be installed in a space served directly or indirectly by a primary heating system, provided that the unit thermal capacity does not exceed 2
    kilowatts or 7,000 Btu/h and is controlled by a time-limiting device not exceeding 30 minutes.
    11. For duct and air handler location: REQ denotes location in conditioned space. When the table indicates ducts and air handlers are in conditioned space, a verification is
    required as specified by Reference Residential Appendix RA3.1.4.3.8.
    12. New dwelling units with a conditioned floor area of 500 square feet or less in Climate Zone 5 may comply with a maximum_U_-factor of 0.30.
    13. Option B meets §150.1(c)9A.
    14. Option C meets §150.1(c)9B.|1. Install the specified_R_-value with an air space present between the roofing and the roof deck, such as standard installation of concrete or clay tile.
    2._ R_-values shown for below roof deck insulation are for wood-framed construction with insulation installed between the framing members. Alternatives including insulation
    above rafters or above roof deck shall comply with the performance standards.
    3. Assembly_U_-factors for exterior framed walls can be met with cavity insulation alone or with continuous insulation alone, or with both cavity and continuous insulation that
    results in an assembly_U_-factor equal to or less than the_U_-factor shown. Use Reference Joint Appendices JA4 Table 4.3.1, 4.3.1(a), or Table 4.3.4 to determine alternative insu-
    lation products to be less than or equal to the required maximum_U_-factor.
    4. Assembly_U_-factors for roofs can be met with cavity insulation alone or with continuous insulation alone, or with both cavity and continuous insulation that results in an
    assembly_U_-factor equal to or less than the_U_-factor shown. Use Reference Joint Appendices JA4 Table 4.2.2 to determine alternative insulation products to be less than or
    equal to the required maximum_U_-factor.R-values shown represent the required insulation to meet the maximum_U_-factor with cavity insulation alone.
    5. Mass wall has a heat capacity greater than or equal to 7.0 Btu/h-ft2.
    6. “Interior” denotes insulation installed on the inside surface of the wall. “Exterior” denotes insulation installed on the exterior surface of the wall.
    7. Below grade “interior” denotes insulation installed on the inside surface of the wall, and below grade “exterior” denotes insulation installed on the outside surface of the wall.
    8. HSPF2 means heating seasonal performance factor.
    9.

  • § 2.5 High relevance — show source text

    Parapet construction R302.2.5 Scope R101.2 Separation R302.2 Structural independence R302.2.6 Trusses

    Steel R505.1.3, R804.3.6 Wood R502.12, R802.10 Tubular Daylighting Device (TDD) (see Skylights) Two-Family Dwellings R302.3

    Under Floor

    Space R408

    Vapor Retarders R702.7 Capillary break R506.2.3.1 Under floor R408.8 Vehicular Gates Appendix BH Veneer

    Masonry R703.7 Ventilation Adjoining rooms R325.1.3 Bathroom and kitchen R325.2

    Habitable rooms R325.1

    Roof R806

    Under floor R408.1 Venting (Mechanical) Chimney and vent connectors R1006 Fireplace R1006 General R325.3

    Violations R113 Visible Transmittance (VT)

    Wall Furnace (see Appliance) Wallboard (see Gypsum) Walls

    Bathtub compartments R327.2 Bracing, steel R603.9 Bracing, wood R602.10 Construction Chapter 6 Covering Chapter 7 Crawl space R202 Cripple R602.9

    INDEX-4 2025 CALIFORNIA RESIDENTIAL CODE

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

    INDEX

    Deflection R301.7

    Exterior, defined R202 Exterior covering R703 Finishes R327.2, R702 Fireplace R1001.5 Foundation R404 Insulating concrete form R608.3, R608.4, R608.5.3 Steel framing R603 Structural insulated panels (SIP) R610 Thickness, masonry chimneys R1003.10 Wood framing R602 Waste

    Construction waste R334

    Water Closet R326.1, R327 Clearances for R327.1 Waterproofing And dampproofing R406 Wells (see Individual Water Supply) Whirlpool Bathtubs R324.3.1, P2720 Wind

    Design criteria R301.2, R301.2.1 Speed maps Figure R301.2(2) Window R609 Emergency Escape and Rescue Openings R319, R321.2.2 Fall protection R321.2 Glazing R324 Light and ventilation R325 Opening limiting devices R321.2.2 Wood

    Floor construction R502

    Foundation walls R404.2 Protection against decay R304 Roof-ceiling construction R802 Shakes R905.8 Shingles R905.7 Trusses R502.12, R802.10 Walls R602

    Yard R318.1, R319.1, R319.2.4, R325.1.1

    2025 CALIFORNIA RESIDENTIAL CODE INDEX-5

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

    INDEX-6 2025 CALIFORNIA RESIDENTIAL CODE

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

    HISTORY NOTE APPENDIX

Frequently asked questions

When do I use Table R702.7(4) vs Table R702.7(5)?

Use § R702.7(4) when you have a Class I or II responsive interior vapor retarder and are allowing CI to be used to control moisture in that context. Use § R702.7(5) when there is no Class I, II or III interior vapor retarder.

What is the R‑value limit for interior insulation when using § R702.7(5)?

The total insulating value on the interior side of the exterior CI (including cavity insulation) shall not exceed R‑5 unless you provide an approved design. § R702.7(5).

Can the exterior continuous insulation serve as the vapor control layer?

Yes — the exterior CI may serve as the vapor control layer if, at installed thickness or with an interior facer, the CI is a Class I or II vapor retarder. Otherwise, place a separate water‑vapor control layer with permeance ≤ 1 perm. § R702.7(5).

Does meeting these tables satisfy the Energy Code?

No. The R‑values in R702.7 tables are moisture‑control prescriptions. They “contribute to but do not supersede” Chapter 11 (California Energy Code) thermal requirements — confirm assembly U‑factor or total thermal compliance separately (see § 150.1).

Are spray‑foam options accepted as CI under these rules?

Spray foam with ≤1.5 perms at installed thickness applied on the interior side of sheathing may be considered to meet R702.7 table requirements if its R‑value alone or combined with exterior CI equals or exceeds the table R‑value; see § R702.7.1 for the two allowable conditions.

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Continuous insulation R‑value requirements to allow interior vapor retarders (1404.3 tables)

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California Energy Code