Title 24 · California Energy Code
Moisture control, continuous insulation and thermal‑bridging controls
This hub orients readers to the California code requirements that link moisture management, continuous insulation and thermal‑bridging control across the Building Code and Title 24 energy rules.
Last reviewed: July 6, 2026
Overview
This part of the code covers how exterior envelope design and materials must manage water and vapor, where continuous insulation (CI) can be used to control moisture, and how CI and other details reduce thermal bridging to meet Title 24 energy requirements. The California Building Code prescribes moisture‑control options for exterior walls (see §1404.3 and associated Tables 1404.3(3)–(5)) and flashing/drainage details to prevent water entry .
The California Energy Code (Title 24, Part 6) integrates CI and thermal‑bridge controls into the energy requirements: see the continuous‑insulation tradeoffs and roof CI tables (e.g., §150.2 and Table 150.2‑E) and the slab‑edge CI rules (Table 110.8‑A) used to meet performance or prescriptive paths . The residential provisions mirror these moisture/CI options (R702.7 and Tables R702.7(3)–(5)) and the Green Building Standards add complementary moisture‑management measures (A6.407) .
In this section
- Continuous insulation R‑value requirements to allow interior vapor retarders (1404.3 tables)
- Residential continuous insulation tables and limits (R702.7(4) and R702.7(5))
- Vapor retarder installation requirements and spray foam criteria for moisture control
- Vented cladding, moisture control and permitted continuous insulation conditions
Code references
Grounded in the retrieved California Energy Code — click a citation to read the verbatim passage:
§ 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:
- The spray foam R -value meets or exceeds the specified continuous insulation R-value.
- 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.
§ 2.5 High relevance — show source text
b**| |4|Vented cladding over wood structural panels
Vented cladding over fiberboard
Vented cladding over gypsum
Continuous insulation with_R_-value ≥ R-2.5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-3.75 over 2 × 6 wall| |5|Vented cladding over wood structural panels
Vented cladding over fiberboard
Vented cladding over gypsum
Continuous insulation with_R_-value ≥ R-5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-7.5 over 2 × 6 wall| |6|Vented cladding over fiberboard
Vented cladding over gypsum
Continuous insulation with_R_-value ≥ R-7.5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-11.25 over 2 × 6 wall| |7|Continuous insulation with_R_-value ≥ R-10 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-15 over 2 × 6 wall| |8|Continuous insulation with_R_-value ≥ R-12.5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-20 over 2 × 6 wall| |a. 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_.|a. 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 wall7 Continuous insulation with_R_-value ≥ R-5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-7.5 over 2 × 6 wall8 Continuous insulation with_R_-value ≥ R-7.5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-10 over 2 × 6 walla. 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. § 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:
- The spray foam R -value is equal to or greater than the specified continuous insulation R -value.
- 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.
§ 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
§ 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 wall7 Continuous insulation with_R_-value ≥ R-5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-7.5 over 2 × 6 wall8 Continuous insulation with_R_-value ≥ R-7.5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-10 over 2 × 6 walla. 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.§ 1404.3.1 High relevance — show source text
�
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:
- The spray foam R -value meets or exceeds the specified continuous insulation R-value.
- 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. Flashing shall be installed at the perimeters of exterior door and window assemblies in accordance with Section 1404.4.1, penetrations and terminations of exterior wall assemblies, exterior wall intersections with roofs, chimneys, porches, decks, balconies and similar projections and at built-in gutters and similar locations where moisture could enter the wall. Flashing with projecting flanges shall be installed on both sides and the ends of copings, under sills and continuously above projecting trim. Where self-adhered membranes are used as flashings of fenestration in exterior wall assemblies, those self-adhered flashings shall comply with AAMA 711. Where fluid applied membranes are used as flashing for exterior wall openings, those fluid applied membrane flashings shall comply with AAMA 714. 1404.4.1 Fenestration flashing. Flashing of the fenestration to the wall assembly shall comply with the fenestration manufacturer’s instructions or, for conditions not addressed by the fenestration manufacturer’s instructions, shall comply with one of the following:
- The water-resistive barrier manufacturer’s flashing instructions.
- The flashing manufacturer’s flashing instructions.
- A flashing design or method of a registered design professional.
- Other approved methods. 1404.4.2 Exterior wall pockets. In exterior walls of buildings or structures, wall pockets or crevices in which moisture can accumulate shall be avoided or protected with caps or drips, or other approved means shall be provided to prevent water damage.
§ 11.25 High relevance — show source text
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. Vented cladding shall include vinyl, polypropylene, or horizontal aluminum siding, brick veneer with a clear airspace as specified in Table R703.8.4(1), 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 thermal envelope requirements of Chapter 11.|a. Vented cladding shall include vinyl, polypropylene, or horizontal aluminum siding, brick veneer with a clear airspace as specified in Table R703.8.4(1), 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 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.§ 1404.3 High relevance — show source text
Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing installed as continuous insulation on the exterior side of frame walls, the
continuous insulation shall comply with Table 1404.3(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 with a Class I vapor retarder on the exterior side, use of a Class I interior vapor retarder that is not a responsive vapor retarder shall require an_approved_ design.
c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing installed as continuous insulation on the exterior side of frame walls, the
continuous insulation shall comply with Table 1404.3(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 with a Class I vapor retarder on the exterior side, use of a Class I interior vapor retarder that is not a responsive vapor retarder shall require an_approved_ design.
c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing installed as continuous insulation on the exterior side of frame walls, the
continuous insulation shall comply with Table 1404.3(4) and the Class I or II vapor retarder shall be a responsive vapor retarder.|TABLE 1404.3(3)—CLASS III VAPOR RETARDERS Col2 ZONE CLASS III VAPOR RETARDERS PERMITTED FOR:a, b 4 Vented cladding over wood structural panels
Vented cladding over fiberboard
Vented cladding over gypsum
Continuous insulation with_R_-value ≥ R-2.5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-3.75 over 2 × 6 wall5 Vented cladding over wood structural panels
Vented cladding over fiberboard
Vented cladding over gypsum
Continuous insulation with_R_-value ≥ R-5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-7.5 over 2 × 6 wall6 Vented cladding over fiberboard
Vented cladding over gypsum
Continuous insulation with_R_-value ≥ R-7.5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-11.25 over 2 × 6 wall7 Continuous insulation with_R_-value ≥ R-10 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-15 over 2 × 6 wall8 Continuous insulation with_R_-value ≥ R-12.5 over 2 × 4 wall
Continuous insulation with_R_-value ≥ R-20 over 2 × 6 walla. 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_.a. § 2.5 Medium relevance — show source text
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. Vented cladding shall include vinyl, polypropylene, or horizontal aluminum siding, brick veneer with a clear airspace as specified in Table R703.8.4(1), 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 thermal envelope requirements of Chapter 11.a. Vented cladding shall include vinyl, polypropylene, or horizontal aluminum siding, brick veneer with a clear airspace as specified in Table R703.8.4(1), 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 thermal envelope requirements of Chapter 11.7-8 2025 CALIFORNIA RESIDENTIAL CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WALL COVERING
§ 7-8 Medium 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. § 504.2 Medium relevance — show source text
504.2**Install VOC compliant resilient flooring systems.
Tier 1. At least 90 percent of the resilient flooring installed shall comply.
**Tier 2.**100 percent of the resilient flooring installed shall comply.||2|2|
|
|
| |A4.504.3Thermal insulation installed in the building shall meet the
following requirements:
Tier 1. Install thermal insulation in compliance with VOC limits.
Tier 2. Install insulation which contains no-added formaldehyde
(NAF) and is in compliance with Tier 1.||2|2|||| |Interior Moisture Control||||||| |4.505.2Vapor retarder and capillary break is installed at slab-on-
grade foundations.||||||| |4.505.3 Moisture content of building materials used in wall and floor
framing is checked before enclosure.||||||| |Indoor Air Quality and Exhaust||||||| |4.506.1 Each bathroom shall be provided with the following:
1. ENERGY STAR fans ducted to terminate outside the building.
2. Fans must be controlled by a humidity control (separate or built-
in); OR functioning as a component of a whole-house ventilation
system.
3. Humidity controls with manual or automatic means of
adjustment, capable of adjustment between a relative humidity
range of≤ 50 percent to a maximum of 80 percent.||||
|
|
| |A4.506.1 Reserved.||||||| |A4.506.2 [HR] Provide filters on return air openings rated MERV 8 or
higher during construction when it is necessary to use HVAC
equipment.||||||| |A4.506.3 Direct-vent appliances shall be used when equipment is
located in conditioned space; or the equipment must be installed in
an isolated mechanical room.||||||| |Environmental Comfort||||||| |4.507.2 Duct systems are sized, designed and equipment is selected
using the following methods:
1. Establish heat loss and heat gain values according to ANSI/ACCA 2
Manual J-2016 or equivalent.
2. Size duct systems according to ANSI/ACCA 1 Manual D-2016
or equivalent.
3. Select heating and cooling equipment according to ANSI/ACCA 3
Manual S-2014 or equivalent.
Frequently asked questions
Where are the required continuous‑insulation R‑values and climate‑zone rules?
CI minimum R‑values and the conditions that allow Class I–III vapor retarders are provided in the CBC tables referenced above: Tables 1404.3(3)–(5) (and the matching residential Tables R702.7(3)–(5)) — consult those tables for climate‑zone specific R‑values and permitted wall assemblies .
Can exterior continuous insulation act as the vapor control layer?
Yes — exterior CI may serve as the vapor control layer when the installed CI (or its facer) qualifies as a Class I or II vapor retarder, or when the prescribed exterior vapor control material is installed per the code conditions; see §1404.3 wording and the related notes in the CI tables for the exact conditions .
How does Title 24 address thermal bridging in roofs and slabs?
Title 24 uses CI as a primary method to reduce thermal bridging and provides tradeoffs (for example Table 150.2‑E for roof CI and Table 110.8‑A for slab insulation) so designers can meet energy performance targets while addressing reflectance, assembly U‑factors and continuous insulation R‑values .
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Prescriptive envelope criteria (U‑factors, R‑values, fenestration limits)
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California Energy Code