CRC · California Residential Code
Definitions of 'Height, Building' and 'Height, Story'
The CRC places the formal definitions in § R202; those definitions control how you measure a building and each story for code limits. Key practical limits are in § R301.3 (e.g., wood‑framed story height **11 ft 7 in**, exception up to **13 ft 7 in** with conditions). Use the CRC definitions and § R301.3 to decide if your planned heights fit the prescriptive rules or require engineered design.
Last reviewed: July 6, 2026
What the code requires — plain English (controlling §)
The California Residential Code places the official definitions of terms used throughout the CRC in § R202. "Height, building" and "Height, story" are defined there and are the terms the code uses to set limits (for example, lateral/wind/seismic rules, story‑height limits and table assumptions). The exact term entries appear in § R202 (Chapter 2, Definitions) in the CRC text.
The single most important point: how you measure a building’s height and each story’s height (the defined terms in § R202) controls which CRC limits and tables apply — especially the story‑height limits in § R301.3.
(Important note: the uploaded CRC file set available to me shows the location of the definitions in § R202 but does not include the full verbatim definition text for those two entries in the retrieved snippets; I cite the code locations below and rely on the CRC sections that use those terms to explain how they are applied. If you want verbatim entries I can extract them if you provide the full § R202 text.)
Requirements in detail
Where these definitions are used
- Story height (the defined term from § R202) is the measurement the CRC uses when applying structural limits such as allowable wall stud heights and the wind/seismic provisions in § R301.3. The CRC lists explicit maximum story heights for different wall systems (wood framing, cold‑formed steel, masonry, ICF, SIPs).
- Building height (the defined term from § R202) is referenced in other chapters and tables (for example wind/wall bracing tables where “mean roof height” or overall building height controls reduction factors). See R608 table notes which reference mean roof height for wind table assumptions.
Key numeric thresholds and where they show up
| Decision item | Value (imperial / metric) | When it matters | Code Reference |
|---|---|---|---|
| Maximum story height — wood wall framing | 11 ft 7 in (3531 mm) | Use to determine applicability of wind/seismic prescriptive provisions; if exceeded, engineered design or exceptions required. | § R301.3 — |
| Alternate permitted story height — wood (limited exception) | 13 ft 7 in (4140 mm) (with conditions: stud clear height ≤ 12 ft (3658 mm), specific stud provisions or engineered design) | Exception path in § R301.3 for taller clear heights with framing conditions/engineered design. | § R301.3 — |
| Maximum bearing wall clear height (masonry) | 13 ft 7 in (4140 mm); bearing wall clear height limit 12 ft (3658 mm) for some controls; +8 ft permitted for gable end walls (exception) | Masonry story height limits referenced in § R301.3. | § R301.3 — |
| Mean roof / code wind table assumption | Example: mean roof height used in wind table derivation 35 ft (used in R608 notes) | Wind/wall bracing tabulated lengths and reduction factors reference mean roof height / building height. | R608 notes / tables — |
(These values come from the CRC's building‑planning limits and R301.3 story‑height rules; the definitions that tell you exactly how to measure are in § R202.)
Short explanation of the two defined terms (synthesis)
- "Height, story" — the code term used to express the vertical clear or nominal height of a story for the purpose of applying story‑height limits in structural and wind/seismic provisions; the story‑height values and exceptions are given in § R301.3.
- "Height, building" — the code term used when code tables and commentary refer to overall building height or mean roof height (for wind tables, reduction factors, area/height limits). R608 notes demonstrate where an overall or mean roof height is a table assumption.
(Again: the CRC places the formal definitions in § R202; see Chapter 2. The CRC excerpts I can access show the locations and all downstream uses but not the verbatim definition lines in the retrieved snippets. If you need the literal dictionary entries I can extract them from the source document.)
Exceptions & special cases
- Mezzanines complying with § R314 are not considered stories for the height/story‑count rules (see the height/limit discussion in § R301.2.2.7). That affects whether a level counts as a story for height limits.
- The § R301.3 story‑height limits differ by structural system (wood, cold‑formed steel, masonry, ICF, SIP). Where a wall system needs to exceed the prescriptive limits, the CRC allows engineered design under Chapter 6 (or reference to the California Building Code for irregular cases).
- Tabulated wind/bracing values are derived using specific mean roof/building height assumptions (R608 notes). For buildings with different mean roof heights the tables allow reduction factors or require interpolation; consult the R608 table notes tied to mean roof height / building height.
Common mistakes
- Treating a wall stud clear‑height limit (e.g., 12 ft (3658 mm) stud clear height) as the same as allowable story height for the whole building. The CRC distinguishes stud/bearing‑wall clear heights from story‑height limits; see § R301.3.
- Forgetting that mezzanines that meet § R314 are not a story (they won’t add to the story count used in height limits). Check § R301.2.2.7 and § R314.
- Using wind/bracing tables without confirming the mean roof or building height assumptions (R608 notes show the wind table derivation depends on a mean roof height assumption). Always check the R608 table notes for reduction factors.
- Relying on jurisdictional zoning “height” language (local zoning) without verifying CRC measurement rules — CRC definitions (§ R202) and code sections control building‑code compliance; local zoning may govern land use/permit limits but measuring for structural code purposes follows the CRC definitions. (The uploaded CRC files show the definitions location, § R202 — if you need the verbatim measurement language I can extract the exact entries.)
Worked example — wood‑framed story height check
Scenario: You are designing a one‑story accessory dwelling with wood wall framing. The finished floor‑to‑ceiling clear height is planned to be 12 ft (3658 mm).
Step 1 — Compare to the CRC story‑height prescriptive limit for wood framing:
- CRC prescriptive story height for wood framing = 11 ft 7 in (3531 mm) per § R301.3.
Step 2 — Does the planned height exceed the prescriptive limit?
- Yes: 12 ft (3658 mm) > 11 ft 7 in (3531 mm).
Step 3 — Can the exception/alternate apply?
- § R301.3 allows a story height up to 13 ft 7 in (4140 mm) under a specific exception if the maximum wall stud clear height does not exceed 12 ft (3658 mm) and other framing/bracing or engineered design conditions are met. Because your planned clear height is exactly 12 ft (3658 mm), you are at the stud clear height threshold — you must ensure the studs and wall bracing comply with the specified Exception conditions (or provide engineered wall framing design per the code).
Conclusion (practical): With a 12 ft clear height you cannot rely solely on the basic prescriptive 11 ft 7 in limit; you must either satisfy all Exception requirements listed in § R301.3 (including stud and bracing provisions) or provide engineered design.
Related provisions (CRC sections)
- § R202 — Definitions (location of the defined terms) —
- § R301.3 — Story height limits and related exceptions (values: 11 ft 7 in, 13 ft 7 in, stud clear heights, etc.) —
- § R301.2.2.7 — Height limitations and story counting (mezzanines, story count rules) —
- R608 (Tables and notes) — Wind/bracing tables and mean roof height assumptions (where building/mean‑roof height matters) —
- R602.3.1 / R602.10 (wood framing exceptions and bracing) — referenced in the story‑height exception text in § R301.3 —
If you want, I can:
- pull and paste the verbatim CRC dictionary entries for "Height, building" and "Height, story" from § R202 (provided the source contains those lines), or
- run measurements from a specific plan and confirm which CRC limits apply given your structural system and chosen clear heights.
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 1.5 High relevance — show source text
2025 CALIFORNIA RESIDENTIAL CODE APPENDIX BK-15
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
APPENDIX BK — COB CONSTRUCTION (MONOLITHIC ADOBE)
TABLE BK106.11(5)—BRACING REQUIREMENTS FOR COB BRACED WALL PANELS BASED ON SEISMIC DESIGN CATEGORY C Col2 Col3 Col4 Col5 Col6 Col7 •
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY C
•
1.5″ PLASTER THICKNESS EACH SIDEg•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY C
•
1.5″ PLASTER THICKNESS EACH SIDEg•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY C
•
1.5″ PLASTER THICKNESS EACH SIDEg•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY C
•
1.5″ PLASTER THICKNESS EACH SIDEgMINIMUM TOTAL LENGTH (feet) OF COB BRACED WALL
**PANELS REQUIRED ALONG EACH BRACED WALL LINEa, b, c, d,CRC § 1.5 High relevance — show source text
APPENDIX BK-14 2025 CALIFORNIA RESIDENTIAL CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
APPENDIX BK — COB CONSTRUCTION (MONOLITHIC ADOBE)
TABLE BK106.11(4)—BRACING REQUIREMENTS FOR COB BRACED WALL PANELS BASED ON SEISMIC DESIGN CATEGORY B—continued Col2 Col3 Col4 Col5 Col6 Col7 •
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY B
•
1.5″ PLASTER THICKNESS EACH SIDEg•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY B
•
1.5″ PLASTER THICKNESS EACH SIDEg•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY B
•
1.5″ PLASTER THICKNESS EACH SIDEg•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY B
•
1.5″ PLASTER THICKNESS EACH SIDEgMINIMUM TOTAL LENGTH (feet) OF COB BRACED WALL
**PANELS REQUIRED ALONG EACH BRACED WALL LINEa, b, c, d,CRC § 2.4.1 High relevance — show source text
R301.2.4.1 Alternative provisions. As an alternative to the requirements in Section R306, ASCE 24 is permitted subject to the limitations of this code and the limitations therein.
R301.3 Story height. The wind and seismic provisions of this code shall apply to buildings with story heights not exceeding the following:
- For wood wall framing, the story height shall not exceed 11 feet 7 inches (3531 mm) and the laterally unsupported bearing wall stud height permitted by Table R602.3(5). Exception: A story height not exceeding 13 feet 7 inches (4140 mm) is permitted provided that the maximum wall stud clear height does not exceed 12 feet (3658 mm), the wall studs are in accordance with Exception 2 or 3 of Section R602.3.1 or an
2025 CALIFORNIA RESIDENTIAL CODE 3-21
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
BUILDING PLANNING
engineered design is provided for the wall framing members, and wall bracing for the building is in accordance with Section R602.10. Studs shall be laterally supported at the top and bottom plate in accordance with Section R602.3. 2. For cold-formed steel wall framing, the story height shall be not more than 11 feet 7 inches (3531 mm) and the unsupported bearing wall stud height shall be not more than 10 feet (3048 mm). 3. For masonry walls, the story height shall be not more than 13 feet 7 inches (4140 mm) and the bearing wall clear height shall be not more than 12 feet (3658 mm). Exception: An additional 8 feet (2438 mm) of bearing wall clear height is permitted for gable end walls. 4. For insulating concrete form walls, the maximum story height shall not exceed 11 feet 7 inches (3531 mm) and the maximum unsupported wall height per story as permitted by Section R608 tables shall not exceed 10 feet (3048 mm). 5. For structural insulated panel (SIP) walls, the story height shall be not more than 11 feet 7 inches (3531 mm) and the bearing wall height per story as permitted by Section R610 tables shall not exceed 10 feet (3048 mm).
For walls other than wood-framed walls, individual walls or wall studs shall be permitted to exceed these limits as permitted by Chapter 6, provided that the story heights of this section are not exceeded. An engineered design shall be provided for the wall or wall framing members where the limits of Chapter 6 are exceeded. Where the story height limits of this section are exceeded, the design of the building, or the noncompliant portions thereof, to resist wind and seismic loads shall be in accordance with the California Building Code .
R301.4 Dead load. The actual weights of materials and construction shall be used for determining dead load with consideration for the dead load of fixed service equipment.
R301.5 Live load. The minimum uniformly distributed live load shall be as provided in Table R301.5.
CRC § 2-5 High relevance — show source text
Part II—Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
CHAPTER 2 DEFINITIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
R201 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
R202 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Part III—Building Planning and Construction . . . . . . . . . . . .3-5
CHAPTER 3 BUILDING PLANNING . . . . . . . . . . . . . . . . . . . . .3-5
R300 Site Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
R301 Design Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
R302 Fire-Resistant Construction . . . . . . . . . . . . . . . . . . . . 3-23
R303 Foam Plastic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-31
R304 Protection of Wood and Wood-Based Products
Against Decay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33
R305 Protection Against Subterranean Termites. . . . . . . 3-35
R306 Flood-Resistant Construction. . . . . . . . . . . . . . . . . . . 3-36
R307 Storm Shelters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40
R308 Site Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40
R309 Automatic Sprinkler Systems . . . . . . . . . . . . . . . . . . . 3-41
R310 Smoke Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-54
R311 Carbon Monoxide Alarms. . . . . . . . . . . . . . . . . . . . . . . 3-58
R312 Minimum Room Areas . . . . . . . . . . . . . . . . . . . . . . . . . 3-59
R313 Ceiling Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-59
CRC § 7.1.1 Medium relevance — show source text
Tabulated lengths for “one story or top story of two story” are based on a floor-to-ceiling height of 10 feet. Tabulated lengths for “first story of two story” are based on floor-
to-ceiling heights of 10 feet each for the first and second story. For floor-to-ceiling heights less than assumed, use the lengths in this table or Table R608.7.1.1(1) or Table
R608.7.1.1(2), or multiply the value in the table by the reduction factor,_R_2, from Table R608.7.1.1(5).
e. Tabulated lengths are based on the default design shear strength of 840 pounds per linear foot of solid wall segment. The tabulated lengths are permitted to be reduced by
multiplying by the applicable reduction factor for design strength,_R_3, from Table R608.7.1.1(6).
f. The reduction factors,_R_1, _R_2 and_R_3, in Table R608.7.1.1(4), Table R608.7.1.1(5), and Table R608.7.1.1(6), respectively, are permitted to be compounded, subject to the limita-
tions of Note b. However, the minimum number and minimum length of solid walls segments in each wall line shall comply with Sections R608.7.1 and R608.7.2.1,
respectively.
g. For intermediate values of sidewall length, endwall length, roof slope and basic wind speed, use the next higher value, or determine by interpolation.|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. The design pressures were used to calculate forces to be resisted by solid wall segments in each sidewall. 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 sidewall. 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 16 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. For buildings with a mean roof height of less than 35 feet, tabulated lengths are permitted to be reduced by multiplying by the appropriate factor,_R_1, from Table R608.7.1.1(4).
The reduced length shall be not less than the “minimum” value shown in the table.
d.CRC § 6.1. Medium relevance — show source text
- The entire length of the braced wall panel does not occur over an opening in the wall below.
- Floor and roof opening. Conditions where an opening in a floor or roof exceeds the lesser of 12 feet (3658 mm) or 50 percent of the least floor or roof dimension.
- Floor level offset. Conditions where portions of a floor level are vertically offset.
Exceptions:
- Framing supported directly by continuous foundations at the perimeter of the building.
- For wood light-frame construction, floors shall be permitted to be vertically offset where the floor framing is lapped or tied together as required by Section R502.6.1.
- Perpendicular shear wall and wall bracing. Conditions where shear walls and braced wall lines do not occur in two perpendicular directions.
- Wall bracing in stories containing masonry or concrete construction. Conditions where stories above grade plane are partially or completely braced by wood wall framing in accordance with Section R602 or cold-formed steel wall framing in accordance with Section R603 include masonry or concrete construction. Where this irregularity applies, the entire story shall be designed in accordance with accepted engineering practice.
Exception: Fireplaces, chimneys and masonry veneer in accordance with this code. 8. Hillside light-frame construction. Conditions in which all of the following apply: 8.1. The grade slope exceeds 1 unit vertical in 5 units horizontal where averaged across the full length of any side of the building.
3-20 2025 CALIFORNIA RESIDENTIAL CODE
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BUILDING PLANNING
8.2. The tallest cripple wall clear height exceeds 7 feet (2134 mm), or where a post and beam system occurs at the building perimeter, the post and beam system tallest post clear height exceeds 7 feet (2134 mm). 8.3. Of the total plan area below the lowest framed floor, whether open or enclosed, less than 50 percent is living space having interior wall finishes conforming to Section R702.
Where Item 8 is applicable, design in accordance with accepted engineering practice shall be provided for the floor immediately above the cripple walls or post and beam system and all structural elements and connections from this diaphragm down to and including connections to the foundation and design of the foundation to transfer lateral loads from the framing above.
Exception: Light-frame construction in which the lowest framed floor is supported directly on concrete or masonry walls over the full length of all sides except the downhill side of the building need not be considered an irregular building under Item 8.
R301.2.2.7 Height limitations. Wood-framed buildings shall be limited to three stories above grade plane or the limits given in Table R602.10.3(3). Wood-framed buildings in Seismic Design Category D 2 exceeding two stories shall be designed for wind and seismic loads in accordance with accepted engineering practice. Cold-formed steel-framed buildings shall be limited to less than or equal to three stories above grade plane in accordance with AISI S230. Mezzanines as defined in Section R202 that comply with Section R314 shall not be considered as stories. Structural insulated panel buildings shall be limited to two stories above grade plane.
CBC § A402 Medium relevance — show source text
SECTION A402—DEFINITIONS
[BS] A402.1 Definitions. Notwithstanding the applicable definitions, symbols and notations in the building code, the following definitions shall apply for the purposes of this chapter:
[BS] ASPECT RATIO. The span-width ratio for horizontal diaphragms and the height-length ratio for shear walls.
[BS] NONCONFORMING STRUCTURAL MATERIALS. Wall bracing materials other than wood structural panels or diagonal sheathing.
[BS] OPEN-FRONT WALL LINE. An exterior wall line, without vertical elements of the lateral force-resisting system, that requires tributary seismic forces to be resisted by diaphragm rotation or excessive cantilever beyond parallel lines of shear walls. Diaphragms that cantilever more than 25 percent of the distance between lines of lateral force-resisting elements from which the diaphragm cantilevers shall be considered to be excessive. Exterior exit balconies of 6 feet (1829 mm) or less in width shall not be considered excessive cantilevers.
[BS] RETROFIT. An improvement of the lateral force-resisting system by alteration of existing structural elements or addition of new structural elements.
[BS] SOFT WALL LINE. A wall line whose lateral stiffness is less than that required by story drift limitations or deformation compatibility requirements of this chapter. In lieu of analysis, a soft wall line may be defined as a wall line in a story where the story stiffness is less than 70 percent of the story above for the direction under consideration.
[BS] STORY. A story as defined by the building code, including any basement or underfloor space of a building with cripple walls exceeding 4 feet (1219 mm) in height.
[BS] WALL LINE. Any length of wall along a principal axis of the building used to provide resistance to lateral loads. Parallel wall lines separated by less than 4 feet (1219 mm) shall be considered to be one wall line for the distribution of loads.
[BS] WEAK WALL LINE. A wall line in a story where the story strength is less than 80 percent of the story above in the direction under consideration.
SECTION A403—ANALYSIS AND DESIGN
[BS] A403.1 General. Modifications required by the provisions in this chapter shall be designed in accordance with the California Building Code provisions for new construction, except as modified by this chapter.
Exception: Buildings for which the prescriptive measures provided in Section A404 apply and are used.
Alteration of the existing lateral force-resisting system or vertical load-carrying system shall not reduce the strength or stiffness of the existing structure, unless the altered structure would remain in conformance to the building code and this chapter.
[BS] A403.2 Scope of analysis. This chapter requires the alteration, repair, replacement or addition of structural elements and their connections to meet the strength and stiffness requirements herein. The lateral load-path analysis shall include the resisting elements and connections from the wood diaphragm immediately above any soft, weak or open-front wall lines to the foundation soil interface or to the uppermost story of a podium structure comprised of steel, masonry, or concrete structural systems that supports the upper woodframed structure. Stories above the uppermost story with a soft, weak or open-front wall line shall be considered in the analysis but need not be modified. The lateral load-path analysis for added structural elements shall include evaluation of the allowable soil-bearing and lateral pressures in accordance with the building code.
CRC § 1.11. Medium relevance — show source text
The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
2025 CALIFORNIA EXISTING BUILDING CODE APPENDIX A-43
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APPENDIX A-44 2025 CALIFORNIA EXISTING BUILDING CODE
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APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS
CHAPTER A4
EARTHQUAKE RISK REDUCTION IN WOOD-FRAME RESIDENTIAL BUILDINGS WITH SOFT, WEAK OR OPEN FRONT WALLS
SECTION A401—GENERAL
[BS] A401.1 Purpose. The purpose of this chapter is to promote public welfare and safety by reducing the risk of death or injury as a result of the effects of earthquakes on existing wood-frame, multiple-unit residential buildings. The ground motions of past earthquakes have caused the loss of human life, personal injury and property damage in these types of buildings. This chapter creates minimum standards to strengthen the more vulnerable portions of these structures. Where fully followed, these minimum standards will improve the performance of these buildings but will not necessarily prevent all earthquake-related damage.
[BS] A401.2 Scope. The provisions of this chapter apply to existing buildings of wood construction that contain residential occupancies and are assigned to Risk Category II, and where the structure has a soft, weak or open-front wall line, and there exists one or more stories above .
SECTION A402—DEFINITIONS
[BS] A402.1 Definitions. Notwithstanding the applicable definitions, symbols and notations in the building code, the following definitions shall apply for the purposes of this chapter:
[BS] ASPECT RATIO. The span-width ratio for horizontal diaphragms and the height-length ratio for shear walls.
[BS] NONCONFORMING STRUCTURAL MATERIALS. Wall bracing materials other than wood structural panels or diagonal sheathing.
[BS] OPEN-FRONT WALL LINE. An exterior wall line, without vertical elements of the lateral force-resisting system, that requires tributary seismic forces to be resisted by diaphragm rotation or excessive cantilever beyond parallel lines of shear walls. Diaphragms that cantilever more than 25 percent of the distance between lines of lateral force-resisting elements from which the diaphragm cantilevers shall be considered to be excessive. Exterior exit balconies of 6 feet (1829 mm) or less in width shall not be considered excessive cantilevers.
[BS] RETROFIT. An improvement of the lateral force-resisting system by alteration of existing structural elements or addition of new structural elements.
[BS] SOFT WALL LINE. A wall line whose lateral stiffness is less than that required by story drift limitations or deformation compatibility requirements of this chapter. In lieu of analysis, a soft wall line may be defined as a wall line in a story where the story stiffness is less than 70 percent of the story above for the direction under consideration.
[BS] STORY. A story as defined by the building code, including any basement or underfloor space of a building with cripple walls exceeding 4 feet (1219 mm) in height.
CRC § 1-18 Medium relevance — show source text
R104 Duties and Powers of the Building Official . . . . . . . 1-18
R105 Permits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
R106 Construction Documents . . . . . . . . . . . . . . . . . . . . . . 1-22
R107 Temporary Structures and Uses . . . . . . . . . . . . . . . . 1-23
R108 Fees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-23
R109 Inspections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-23
R110 Certificate of Occupancy. . . . . . . . . . . . . . . . . . . . . . . 1-25
R111 Service Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-25
R112 Means of Appeals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-25
R113 Violations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-26
R114 Stop Work Order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-26
Part II—Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
CHAPTER 2 DEFINITIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
R201 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
R202 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Part III—Building Planning and Construction . . . . . . . . . . . .3-5
CHAPTER 3 BUILDING PLANNING . . . . . . . . . . . . . . . . . . . . .3-5
R300 Site Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
R301 Design Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
R302 Fire-Resistant Construction . . . . . . . . . . . . . . . . . . . . 3-23
CRC § 2.4 Medium relevance — show source text
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
Frost protection R403.1.4.1 Scope R101.2, R102.6.1 Smoke alarms R310.2.2 Address (Site) R308 Administration, California Chapter 1, Division 1
General 1.1 Dept. of Housing and Community Development 1.8 Office of the State Fire Marshal 1.11 Administration, Division II Chapter 1 Applicability R102 Certificate of occupancy R110 Construction documents R106 Department of building safety R103 Duties and Powers R104
Fees R106
Inspections R109 Means of appeals R112 Permits R105, R105.5.1 Purpose R101.3 Service utilities R111 Stop work order R114 Temporary structures and uses R107 Violations R113 Aging-in-place Design and Fall Prevention R327
Doorbell buttons R327.1.4 Electrical receptacle outlet, switch and control heights R327.1.2 Interior doors R327.1.3 Reinforcement for grab bars R327.1.1 Allowable Spans Of floor joists R502.3, R505.3.2 Of headers R602.7, R603.6 Of rafters and ceiling joists R802.4, R802.5, R804.3.1, R804.3.2 Alternate Materials (see Materials) R104.11 Alterations (see Existing Buildings) Anchor Bolts R403.1.6
Appeal Board of 1.8.8, Appendix AA Means of 1.8.8, R112 Appliance Flue area R1003.14
CRC § 8.4 Medium relevance — show source text
Floor R503.3
Walls R605 Patio Covers Appendix BF Penetrations R302.4, R302.5 Permits 1.8.4, R105, R105.5.1 Permit fees Appendix AB Photovoltaic Panel Systems R907 Ground-mounted definition R202
Photovoltaic Support Structure, Elevated R202, R324.8, R324.8.1, R324.8.2 Piers R606.7
Masonry R404.1.9 Planning Building Chapter 3 Plans R106
Plaster
Exterior R703.7
Interior R702.2
Platform Lifts R323.2, R323.3 Plumbing Fixture clearances R327
Fixtures R326, R327 Inspection 109.1.2 Requirements and definitions R202 System, definition R202 Plywood Application R703.5 Materials, walls R604
Precast Concrete
Footings R403.4 Foundation material R402.3.1
Foundation walls R404.5
Protection Against decay and termites R304, R305 Against radon Appendix BE Public Way R318.1, R319.1 Purlins R802.4.5
Hot Tubs (see Swimming Pools) R324.3.1, R328 Hurricane (see Storm Shelter)
Impact Protective System Energy storage system R330.8 Flood R306.1.4.2, R306.3.3 Human impact R324.3 Storm shelter R307.2.1
Windborne debris R301.2.1.2 Indirectly Conditioned Space (see Conditioned Space) Inflatable Amusement Device
Defined R202
Inlet To masonry chimneys R1003.16 Inspection On-site 1.8.4, R109.1 Insulation
Above-deck R906 Flame spread R302.10 Foam plastic R303 Interior
Lath R702.2.3
Other finishes R702.5
Plaster R702.2 Wall covering Chapter 7 Intermodal Shipping Container R301.1.4
Joist
Bearing R502.6, R606.6.3.1
Kitchen Height and area R312, R313 Sinks R326
Ventilation R325.1.2
Labeling Garage doors R609.4.1 Ladders
Ships ladders R318.7.13 Sleeping lofts R315.5.3 Landings (see also Stairways, Ramps and Doors) R318.3, R318.3.1, R318.3.2, R318.7.6, R318.8.2, R321, R324.4.7, R325.6, R325.7 Lateral Support R502.7, R606.6.4, R607.5.2 Lath
Exterior R703.7.1
Interior R702.2.3
Lavatories R326.1
Clearances R327 Liability R104.8 Light R325 Lighting Adjoining rooms R325.1.3 Bathrooms R325.2
CRC § 2.3.1 Medium relevance — show source text
2025 CALIFORNIA RESIDENTIAL CODE APPENDIX CK-7
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APPENDIX CK-8 2025 CALIFORNIA RESIDENTIAL CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
2025 CALIFORNIA RESIDENTIAL CODE APPENDIX NA-1
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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
CRC § 1.5 Medium relevance — show source text
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
APPENDIX BK — COB CONSTRUCTION (MONOLITHIC ADOBE)
TABLE BK106.11(3)—BRACING REQUIREMENTS FOR COB BRACED WALL PANELS BASED ON SEISMIC DESIGN CATEGORY A Col2 Col3 Col4 Col5 Col6 Col7 •
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SEISMIC DESIGN CATEGORY A
•
1.5″ PLASTER THICKNESS EACH SIDEg•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SEISMIC DESIGN CATEGORY A
•
1.5″ PLASTER THICKNESS EACH SIDEg•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SEISMIC DESIGN CATEGORY A
•
1.5″ PLASTER THICKNESS EACH SIDEg•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SEISMIC DESIGN CATEGORY A
•
1.5″ PLASTER THICKNESS EACH SIDEgMINIMUM TOTAL LENGTH (feet) OF COB BRACED WALL
PANELS REQUIRED ALONG EACH BRACED WALL LINEa, b, c, d, eMINIMUM TOTAL LENGTH (feet) OF COB BRACED WALL
**PANELS REQUIRED ALONG EACH BRACED WALL LINEa, b, c, d,CRC § 1.5 Medium relevance — show source text
11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY C
•
1.5″ PLASTER THICKNESS EACH SIDEg|•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY C
•
1.5″ PLASTER THICKNESS EACH SIDEg|•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY C
•
1.5″ PLASTER THICKNESS EACH SIDEg|•
SOIL CLASS Df
•
TOTAL WALL HEIGHT = 10 FEET (INCLUDING STEM WALL AND BOND BEAM)
•
COB WALL HEIGHT PER TABLE BK106.11(1)
•
15 PSF ROOF-CEILING DEAD LOADd
•
STORY LOCATION: ONE-STORY BUILDING
•
SESIMIC DESIGN CATEGORY C
•
1.5″ PLASTER THICKNESS EACH SIDEg|MINIMUM TOTAL LENGTH (feet) OF COB BRACED WALL
PANELS REQUIRED ALONG EACH BRACED WALL LINEa, b, c, d, e|MINIMUM TOTAL LENGTH (feet) OF COB BRACED WALL
PANELS REQUIRED ALONG EACH BRACED WALL LINEa, b, c, d, e|MINIMUM TOTAL LENGTH (feet) OF COB BRACED WALL
PANELS REQUIRED ALONG EACH BRACED WALL LINEa, b, c, d, e| | Braced wall**
line spacing
(feet)|** Braced wall**
line length
(feet)|** Min. braced wall**
line % openings|** Min.California Residential Code Medium relevance — show source text
|100 psf|1 hr
23 min|||7|1, 2|11/3| |F/C-4-RC-9|4″|4″ deep (4370 psi);1/4″ reinforcement bars
at 6″ pitch with3/4″ cover;1/4″ main rein-
forcement bars at 4″ pitch perpendicular
with1/2″ cover; 13′1″ span restrained.|150 psf|2 hrs|||7|1, 3|2| |F/C-4-RC-10|4″|4″ thick (5140 psi) deck;1/4″ reinforce-
ment bars at 71/2″ pitch with7/8″ cover;3/8″
main reinforcement bars at 33/4″ pitch
perpendicular with1/2″ cover; 13′1″ span
restrained.|140 psf|1 hr
16 min|||7|1, 5|11/4| |F/C-4-RC-11|4″|4″ thick (4000 psi) concrete deck;
3″ × 11/2″ × 4 lbs R.S.J.; 2′6″ C.R.S.; flush
with top surface; 4″ × 6″ x 13 SWG mesh
reinforcement 1″ from bottom of slab; 6′6″
span restrained.|150 psf|2 hrs|||7|1, 3|2| |F/C-4-RC-12|4″|4″ deep (2380 psi) concrete deck;
3″ × 11/2″ × 4 lbs R.S.J.; 2′6″ C.R.S.; flush
with top surface; 4″ × 6″ x 13 SWG mesh
reinforcement 1″ from bottom surface;
6′6″ span restrained.|150 psf|1 hr
3 min|||7|1, 2|1| |F/C-4-RC-13|41/2″|41/2″ thick (5200 psi) deck;1/4″ reinforce-
ment bars at 71/4″ pitch with7/8″ cover;3/8″
main reinforcement bars at 33/4″ pitch
perpendicular with1/2″ cover; 13′1″ span
restrained.|140 psf|2 hrs|||7|1, 3|2| |F/C-4-RC-14|41/2″|41/2″ deep (2525 psi) concrete deck;1/4″
reinforcement bars at 71/2″ pitch with7/8″
cover;3/8″ main reinforcement bars at
33/8″ pitch perpendicular with1/2″ cover;
13′1″ span restrained.|150 psf|42 min|||7|1, 5|2/3| |F/C-4-RC-15|41/2″|41/2″ deep (4830 psi) concrete deck;
11/2″ × No.CRC § 0.0929 Medium relevance — show source text
000|27,100|18,000|27,100|18,000|21,100|12,000| |MAXIMUM HEIGHT IN STORIES|MAXIMUM HEIGHT IN STORIES|MAXIMUM HEIGHT IN STORIES|MAXIMUM HEIGHT IN STORIES|MAXIMUM HEIGHT IN STORIES|MAXIMUM HEIGHT IN STORIES|MAXIMUM HEIGHT IN STORIES|MAXIMUM HEIGHT IN STORIES| |Unlimited|12|4|2|4|2|3|2| |MAXIMUM HEIGHT IN FEET|MAXIMUM HEIGHT IN FEET|MAXIMUM HEIGHT IN FEET|MAXIMUM HEIGHT IN FEET|MAXIMUM HEIGHT IN FEET|MAXIMUM HEIGHT IN FEET|MAXIMUM HEIGHT IN FEET|MAXIMUM HEIGHT IN FEET| |Unlimited|160|65|55|65|55|50|40| |For SI: 1 square foot = 0.0929 m2.
a. See Section C102 for unlimited area under certain conditions.|For SI: 1 square foot = 0.0929 m2.
a. See Section C102 for unlimited area under certain conditions.|For SI: 1 square foot = 0.0929 m2.
a. See Section C102 for unlimited area under certain conditions.|For SI: 1 square foot = 0.0929 m2.
a. See Section C102 for unlimited area under certain conditions.|For SI: 1 square foot = 0.0929 m2.
a. See Section C102 for unlimited area under certain conditions.|For SI: 1 square foot = 0.0929 m2.
a. See Section C102 for unlimited area under certain conditions.|For SI: 1 square foot = 0.0929 m2.
a. See Section C102 for unlimited area under certain conditions.|For SI: 1 square foot = 0.0929 m2.
a. See Section C102 for unlimited area under certain conditions.|C102.2 One-story unlimited area. The area of a one-story Group U agricultural building shall not be limited if the building is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.
C102.3 Two-story unlimited area. The area of a two-story Group U agricultural building shall not be limited if the building is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width and is provided with an approved automatic sprinkler system throughout in accordance with Section 903.3.1.1.
SECTION C103—MIXED OCCUPANCIES
C103.1 Mixed occupancies. Mixed occupancies shall be protected in accordance with Section 508.
APPENDIX C-2 2025 CALIFORNIA BUILDING CODE
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APPENDIX C—GROUP U—AGRICULTURAL BUILDINGS
SECTION C104—EXITS
C104.1 Exit facilities. Exits shall be provided in accordance with Chapter 11A or 11B as applicable.
Exceptions:
- The maximum travel distance from any point in the building to an approved exit shall not exceed 300 feet (91 440 mm).
- One exit is required for each 15,000 square feet (1393.5 m [2] ) of area or fraction thereof.
CRC § 9.1 Medium relevance — show source text
Defined R202 Chimneys Caps R1003.9.1 Clearance R1003.18 Corbeling R1003.5 Crickets R1003.20 Design (masonry) R1003.1 Factory-built R1005 Fireblocking R1003.19 Fireplaces Chapter 10 Flue area R1003.14, R1003.15 Flue lining R1003.11 Load R1003.8 Multiple flue R1003.14 Rain caps R1003.9.3 Spark arrestors R1003.9.2 Termination R1003.9
Wall thickness R1003.10
Clay Tiles R905.3
Cleanout Masonry chimney R1003.17 Climate Types R301.2 Climate Zones R202, R702.7.3, Table R702.7(5) Columns R407
2025 CALIFORNIA RESIDENTIAL CODE INDEX-1
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INDEX
Live load R301.5
Nominal sizes R301.8
Roof load R301.6
Seismic R301.2.2
Snow loads R301.2.3 Story height R301.3 Sunrooms R301.2.1.1.1
Wind R301.2.1
Doors
Egress R318.2 Exterior R318.3, R609 Glazing R324 Draftstopping R302.12, R502.13 Drainage Foundation R405 Site drainage R300 Ducts
Defined R202 Dwelling-garage wall and ceiling penetration R302.5.2 System, definition R202 Dwelling Unit Separation R302.2, R302.3 Sprinklers (see Automatic Sprinkler System)
Electric Vehicle Charging Stations R317.6 Elevator R323.1, R323.3 Emergency Escape and Rescue Openings R319
Additions R319.6
Area wells R319.4 Bars, grilles, covers and screens R319.4.4
Basements, existing R319.7 Dimensions R319.2
Doors R319.3
Replacement window R319.5 Under decks and porches R319.2.4 Where required R319.1 Window fall protection R321.2 Emergency Housing Appendix CJ Energy Storage Systems R328 ESS vehicle impact protection Figure R330.8.1 Maximum aggregate ratings of ESS Table R330.5 Protection from impact R330.8 Toxic and highly toxic gas R330.12 Entry 1.8.5, R104.4 Existing Buildings Appendix BO Administrative R101.2, R102.6, R105.1, R105.8, R106.2, R113.1, R113.2 Basements R313.1.2, R319.7 Carbon monoxide alarms R311.2.2, R311.5, R311.6 Flood R104.3.1
CRC § 2.3 Medium relevance — show source text
SIP R610.8
Steel R603.6
Wood R602.7
Hearth R1001.9
Extension R1001.10, R1001.9
Heaters
Masonry R1002 Heating Required R325.8 Height Ceiling R313 Mezzanines R314.2 Sleeping lofts R315.3 Hollow-Unit Masonry (see Masonry)
INDEX-2 2025 CALIFORNIA RESIDENTIAL CODE
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INDEX
Roof shingles R905.4 Methods Water distribution pipe sizing Appendix CF Mezzanines (see also Sleeping Lofts) R314, R321 Modifications R104.2.3 Moisture Content, Building Materials R109.1.4.1
Moisture Control R702.7
Mortar
Joints R606.3.1 Multiple Flues R1003.13
Natural Light (see Light) Natural Ventilation (see Ventilation) Notching Steel joists R505.2.5, R505.3.5, R804.2.5, R804.3.3 Steel studs R603.2.6, R603.3.4 Wood joists R502.8, R802.7.1 Wood studs R602.6 Wood top plates R602.6.1
Opening Protection R302.5
Parapets R302.2.2, R606.4.4 Particleboard
Floor R503.3
Walls R605 Patio Covers Appendix BF Penetrations R302.4, R302.5 Permits 1.8.4, R105, R105.5.1 Permit fees Appendix AB Photovoltaic Panel Systems R907 Ground-mounted definition R202
Photovoltaic Support Structure, Elevated R202, R324.8, R324.8.1, R324.8.2 Piers R606.7
Masonry R404.1.9 Planning Building Chapter 3 Plans R106
Plaster
Exterior R703.7
Interior R702.2
Platform Lifts R323.2, R323.3 Plumbing Fixture clearances R327
Fixtures R326, R327 Inspection 109.1.2 Requirements and definitions R202 System, definition R202 Plywood Application R703.5 Materials, walls R604
Precast Concrete
Footings R403.4 Foundation material R402.3.1
Foundation walls R404.5
Protection Against decay and termites R304, R305 Against radon Appendix BE Public Way R318.1, R319.1 Purlins R802.4.5
Hot Tubs (see Swimming Pools) R324.3.1, R328 Hurricane (see Storm Shelter)
Impact Protective System Energy storage system R330.8 Flood R306.1.4.2, R306.3.3 Human impact R324.3 Storm shelter R307.2.1
CRC § 2023-17 Medium relevance — show source text
changes in the handbook https://www.hud.gov/sites/dfiles/OCHCO/documents/2023 17hsgml.pdf. Interested parties should look to HUD’s website for any updates.
Freddie Mac Freddie Mac now offers several options for adding an ADU to an existing home and financing a purchase with the intention to rent or build an ADU. This includes allowing rental income from ADUs to be included in qualified income for a loan.
24
For more information, please visit https://sf.freddiemac.com/docs/pdf/fact-sheet/adu-fact- sheet.pdf.
Fannie Mae Fannie Mae now offers financing options for adding an ADU to an existing property, building a home with an ADU using Construction-to-Permanent Financing, and buying a home with an existing ADU.
[For more information, please visit https://singlefamily.fanniemae.com/originating](https://singlefamily.fanniemae.com/originating-underwriting/mortgage-products/accessory-dwelling-units)underwriting/mortgage-products/accessory-dwelling-units.
Height Requirements
Is there a limit on the height of an ADU? There is no height limit contained in State ADU Law, but local agencies may impose height limits pursuant to Government Code section 66321, subdivision (b)(4). A local agency may impose a height limit by adopting a compliant ADU ordinance.
A local agency may not impose a height limit that is less than the following:
Detached ADUs
16 feet on a lot with a proposed or existing single-family or multifamily dwelling unit (Gov. Code, § 66321, subd. (b)(4)(A)).
18 feet on a lot with an existing or proposed single-family or multifamily dwelling, including an additional 2 feet to accommodate roof pitch that aligns with the primary dwelling, when the lot is a half-mile from a major transit stop or high-quality transit corridor (Gov. Code, § 66321, subd. (b)(4)(B)). Please see the ADU Glossary for definitions of these terms.
18 feet height on a lot with an existing or proposed multifamily, multistory dwelling (Gov. Code, § 66321, subd. (b)(4)(C)).
If a detached two-story ADU can be built according to the height allowances required under State ADU Law while remaining compliant with the building code, a local agency cannot deny an ADU application to create a two-story ADU, irrespective of the underlying zoning that might restrict a primary dwelling to one story. (Gov. Code, §§ 66321, subd. (b)(4)(D); 66314, subd. (d)(8).)
Attached ADUs
25 feet or the height limitation that applies to the primary dwelling in the local zoning ordinance, whichever is lower (Gov. Code, § 66321, subd. (b)(4)(D)).
25
Is there a limit on the number of stories of an ADU? There is no limit on the number of stories contained in State ADU Law. A local agency must allow at least two stories, and an attached ADU may be built to the height of the zoning for the primary dwelling or up to 25 feet, whichever is lower. (Gov. Code, § 66321, subd. (b)(4)(D).)
CRC § 2025 Medium relevance — show source text
It is important to understand that the IRC contains coverage for what is conventional and common in residential construction practice. While the IRC will provide all of the needed coverage for most residential construction, it might not address construction practices and systems that are atypical or rarely encountered in the industry. Therefore, the IRC contains several references to other codes either as an alternative to the provisions of the IRC or where the IRC lacks coverage for a particular type of structure, design, system, appliance or method of construction. In other words, the IRC is meant to be all inclusive for typical residential construction and it relies on other codes only where alternatives are desired or where the code lacks coverage for the uncommon aspect of residential construction. Of course, the IRC constantly evolves to address new technologies and construction practices that were once uncommon, but are now common.
The IRC is unique in that much of it, including Chapters 3 through 9 and Chapters 34 through 43, is presented in an ordered format that is consistent with the normal progression of construction, starting with the design phase and continuing through the final trimout phase. This is consistent with the “cookbook” philosophy of the IRC.
2025 CALIFORNIA RESIDENTIAL CODE xiii
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Arrangement and Format of the 2025 CRC
The CRC is divided into nine main parts, specifically: Part I—Administrative, Part II—Definitions, Part III—Building Planning and Construction, Part IV—Energy Conservation, Part V—Mechanical, Part VI—Fuel Gas, Part VII—Plumbing, Part VIII—Electrical and Part IX—Referenced Standards. Parts IV through VIII of IRC are not adopted in California and replaced with references to appropriate parts of Title 24. The following provides a brief description of the content of each chapter and appendix of the CRC:
Chapter 1 Scope and Administration.
Chapter 1 establishes the limits of applicability of the code and describes how the code is to be applied and enforced. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the design professional, contractor and property owner.
Chapter 2 Definitions.
Chapter 2 is the repository of the definitions of terms used in the body of the code. The user of the code should be familiar with and consult this chapter because the definitions are essential to the correct interpretation of the code and because the user may not be aware that a term is defined.
Chapter 3 Building Planning.
Chapter 3 provides guidelines for a minimum level of structural integrity, life safety, fire safety and livability for inhabitants of dwelling units regulated by this code. Chapter 3 is a compilation of the code requirements specific to the building planning sector of the design and construction process. This chapter sets forth code requirements dealing with light, ventilation, sanitation, minimum room size, ceiling height and environmental comfort. Chapter 3 establishes life-safety provisions including limitations on glazing used in hazardous areas, specifications on stairways, use of guards at elevated surfaces, window and fall protection, and rules for means of egress. Snow, wind and seismic design live and dead loads and flood-resistant construction, as well as solar energy systems are addressed in this chapter.
Chapter 4 Foundations.
Frequently asked questions
Where exactly do I find the CRC definition entries for these terms?
The formal entries are in § R202 (Chapter 2, Definitions). The CRC file I can access shows the definitions are located there but the retrieved snippets do not include the literal dictionary lines; I can extract and supply the verbatim text if you want me to pull § R202.
If my story height is 11 ft 8 in, do I automatically need engineered design?
Not automatically — § R301.3 sets 11 ft 7 in as the prescriptive wood‑framing story limit; heights above that will need to satisfy the stated exception conditions (which include limits on stud clear height, bracing, or an engineered framing design). Review the exception language in § R301.3 to see if you meet the conditions, otherwise provide engineered design.
Does “building height” used in zoning equal the CRC “height, building”?
Not necessarily. Local zoning definitions can differ. For code compliance (wind, seismic, bracing tables) use the CRC definitions in § R202 and the applicable code sections; confirm zoning separately with your local planning department.
Do mezzanines count as a story for height limits?
Mezzanines that comply with § R314 are not considered stories for story‑count/height limit purposes per the CRC (see § R301.2.2.7).
Where do I check the wind/bracing table assumptions that reference building height?
Check the R608 table notes and associated tables — they state the mean roof height and other assumptions used to derive the tabulated lengths and identify reduction factors for different mean roof heights.
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