CRC · California Residential Code
Which ACI concrete standards does the CRC reference for foundations, slabs and structural concrete?
The CRC points you to **ACI 318** for general structural concrete and **ACI 332** for residential slabs and many foundation walls (with **PCA 100** allowed as an alternative for foundation walls). Check **§ R402.2** for compressive‑strength requirements (Table R402.2), **§ R404.1.3** for foundation‑wall design options, and **§ R506.1** for slab‑on‑grade minimums (3 1/2" slab, base requirements).
Last reviewed: July 6, 2026
What the code requires — 2–4 sentences
The California Residential Code requires that concrete materials, testing and many constructive details for foundations, slabs and other structural concrete comply with the appropriate ACI standards. The CRC specifically points to ACI 318 and ACI 332 for structural concrete and residential concrete provisions, and also allows PCA 100 for foundation-wall design in the foundation-wall provision — see § R402.2, § R404.1.3 and § R506.1.
The single most important practical rule: use ACI 318 for general structural concrete and ACI 332 for residential slabs and foundation walls where the CRC references them — check the specific CRC table or section cited for mandatory dimensions and compressive-strength requirements.
Requirements in detail
Which ACI documents the CRC references (plain list)
- ACI 318 — Building Code Requirements for Structural Concrete (referenced for structural concrete design and testing and called out by the CRC).
- ACI 332 — Residential Code Requirements for Structural Concrete (specifically referenced for slab‑on‑ground floors and residential foundation walls).
- PCA 100 — (Portland Cement Association guidance) is permitted as an alternative for concrete foundation‑wall design where § R404.1.3 allows it.
(These references are listed in the CRC referenced-standards list and are explicitly cited in the controlling sections named below.)
Key code calls and where they apply
- § R402.2 — Materials: the CRC requires specified compressive strength be as shown in Table R402.2, and states that materials and testing must comply with the applicable standards in Chapters 19 and 20 of ACI 318 or ACI 332.
- § R404.1.3 — Concrete foundation walls: foundation walls “shall be designed and constructed in accordance with the provisions of this section, ACI 318, ACI 332 or PCA 100.” It also references the CRC’s own reinforcement tables for minimum reinforcement and cross-section limits (see the suite of Table R404.1.3.2 entries).
- § R506.1 — Concrete floors (on ground): slab-on-ground floors “shall be designed and constructed in accordance with the provisions of this section or ACI 332.” The section also sets the minimum slab thickness and ties the slab compressive-strength requirement back to § R402.2.
Decision‑relevant dimensions/values (code quick‑reference)
| Item | Value / Rule | Code Reference |
|---|---|---|
| Minimum slab‑on‑ground thickness | 3 1/2 inches (89 mm) minimum | § R506.1 |
| Base course under below‑grade slab | 4‑inch (102 mm) base course when slab is below grade | § R506.3.2 |
| Fill depth limits (when used without special approval) | 24 in max for clean sand/gravel; 8 in max for earth | § R506.3.1 |
| Specified compressive strength (f′c) | See Table R402.2 (CRC sets f′c values in that table) | § R402.2 |
| Standards for materials & testing | Use Chapters 19 & 20 of ACI 318 or ACI 332 as applicable | § R402.2 |
| Foundation wall design options | Design per CRC section, ACI 318, ACI 332, or PCA 100 | § R404.1.3 |
How the choice between ACI 318 and ACI 332 works in practice
- Use ACI 332 when the CRC explicitly permits it (slabs-on-ground and many residential foundation walls) — § R506.1 and § R404.1.3 name ACI 332 directly.
- Use ACI 318 for structural concrete that falls under general structural rules or where the CRC directs materials/testing to ACI 318 chapters (and for details not covered by ACI 332). § R402.2 and the referenced standards list show ACI 318 as the principal structural reference.
Exceptions & special cases
- R404.1.3 allows foundation walls to be designed with ACI 318, ACI 332 or PCA 100; when one of those is used, the CRC permits project drawings/details to omit an architect/engineer seal unless state law requires one. That is a limited administrative exception — § R404.1.3.
- Post‑tensioned slab‑on‑ground floors are outside ACI 332 prescriptive provisions and must follow PTI DC10.5 (see § R506.2).
- The CRC ties durability (air entrainment for freeze/thaw exposure) and maximum supplementary‑cementitious-material use for certain exterior slabs to ACI provisions (see § R402.2). If a needed numeric value or limit is found only in a CRC table (for example Table R402.2), consult that table in the CRC because it is the controlling source.
If a specific numeric value (for example, the exact minimum f′c for a particular application) is needed you must consult Table R402.2 in the CRC — that table is the code’s authoritative source for f′c and is referenced by § R402.2. The file excerpts available here show the code points to the table but do not reproduce all table entries; therefore I cannot quote those numeric values here without the table text.
Common mistakes
- Assuming ACI 318 always governs residential slabs: the CRC explicitly allows ACI 332 for slabs‑on‑ground and many residential foundation walls — check § R506.1 and § R404.1.3 before defaulting to ACI 318.
- Overlooking the CRC tables: the CRC sets the minimum f′c and many dimensions in its own tables (e.g., Table R402.2) — do not substitute an assumed compressive strength without checking the table. § R402.2.
- Forgetting administrative exceptions: when using ACI 318/332 or PCA 100 for foundation walls, the CRC allows omission of the design professional’s seal in many cases — but local/state law may still require a seal; see § R404.1.3.
Worked example — applying the rule with numbers (how to check compliance)
Scenario: You are building a slab‑on‑grade living area (not post‑tensioned). You plan a 4‑inch concrete slab on a 4‑inch clean‑graded sand base.
- Minimum slab thickness — check § R506.1: the CRC requires slabs‑on‑ground to be not less than 3 1/2 inches (89 mm). A 4‑inch slab meets that requirement.
- Base course — check § R506.3.2: a 4‑inch (102 mm) base course is required where the slab is below grade; your 4‑inch base complies.
- Fill compaction limits — if you intend to place fill under the slab, check § R506.3.1: clean sand/gravel fill depths should not exceed 24 inches without special approval. If you have deeper fill, you must get local approval or change the design.
- Compressive strength f′c — § R506.1 ties slab f′c back to § R402.2. You must verify the required f′c in Table R402.2 (the CRC table is the controlling source for the numeric f′c value). Because the table entries aren’t reproduced in these excerpts, consult the CRC Table R402.2 for the exact psi value. Do not assume a numeric f′c without checking Table R402.2.
- Design standard — since this is a residential slab‑on‑ground, the CRC allows design and construction per ACI 332 (or per § R506 provisions). Use ACI 332 for reinforcement and construction details unless the project circumstances require ACI 318.
Summary of the check: Thickness and base are compliant by the CRC numbers; check Table R402.2 for required f′c and use ACI 332 for slab details as allowed by § R506.1.
Related provisions (quick list)
- § R402.2 — Concrete materials, minimum specified compressive strength (Table R402.2), and ACI material/testing linkage.
- § R404.1.3 — Concrete foundation walls: design per CRC section, ACI 318, ACI 332, or PCA 100; references to the reinforcement tables.
- § R506.1 — Concrete floors (on ground): design per section or ACI 332; minimum slab thickness; link to § R402.2 for f′c.
- Table R402.2 — (See § R402.2) — Code table controlling minimum f′c for various applications.
- Associated CRC tables for foundation‑wall reinforcement: Table R404.1.3.2(1) and the series of R404.1.3.2 tables for vertical/horizontal reinforcement.
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 44-2 High relevance — show source text
44-2 2025 CALIFORNIA RESIDENTIAL CODE
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Part IX— Referenced Standards
44 REFERENCED STANDARDS
Notwithstanding California laws and regulations, these referenced standards shall be applicable only to those California Residential Code sections that are adopted.
User notes:
About this chapter: The one- and two-family dwelling code contains numerous references to standards promulgated by other organizations that are used to provide requirements for materials, products and methods of construction. Chapter 44 contains a comprehensive list of all standards that are referenced in this code. These standards, in essence, are part of this code to the extent of the reference to the standard.
This chapter lists the standards that are referenced in various sections of this document. The standards are listed herein by the promulgating agency of the standard, the standard identification, the effective date and title, and the section or sections of this document that reference the standard. The application of the referenced standards shall be as specified in Section R102.4.
ABTG Applied Building Technology Group LLC6300 Enterprise Lane Madison, WI 53719
ANSI/ABTG FS 100—2012 (R2018): Standard Requirements for Wind Pressure Resistance of Foam Plastic Insulation Sheathing Used in Exterior Wall Covering Assemblies
R303.8
ACCA Air Conditioning Contractors of America 1330 Braddock Place, Suite 350 Alexandria, VA 22314
ANSI/ACCA 2 Manual J—2016: Residential Load Calculation
Table R301.2
ACI American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331
318—19: Building Code Requirements for Structural Concrete R402.2, R404.1.3, R404.1.3.1, Table R404.1.3.2(2), Table R404.1.3.2(5), Table R404.1.3.2(6), Table R404.1.3.2(7), Table R404.1.3.2(8), R404.1.3.3, R404.1.3.4, R404.1.4.2, R404.5.1, R608.1, R608.1.1, R608.1.2, R608.2, R608.5.1, R608.6.1, R608.8.2, R608.9.2, R608.9.3
332—20: Residential Code Requirements for Structural Concrete
R402.2, R403.1, R404.1.3, R404.1.3.4, R404.1.4.2, R506.1
AISI American Iron and Steel Institute 25 Massachusetts Avenue, NW Suite 800 Washington, DC 20001
AISI S100—16 (2020) w/S2—20: North American Specification for the Design of Cold-Formed Steel Structural Members, 2016 Edition (Reaffirmed 2020), with Supplement 2, 2020 Edition
R608.9.2, R608.9.3
AISI S220—20: North American Standard for Cold-Formed Steel Nonstructural Framing, 2020 Edition
R702.3.3
AISI S230—19: North American Standard for Cold-Formed Steel Framing—Prescriptive Method for One and Two Family Dwellings, 2019 Edition
CRC § 1.3.3.7.6 Medium relevance — show source text
Vertical reinforcement with a yield strength of less than 60,000 psi and bars of a different size than specified in the table are permitted in accordance with Section
R404.1.3.3.7.6 and Table R404.1.3.2(9).
d. NR indicates vertical wall reinforcement is not required, except for 6-inch nominal walls formed with stay-in-place forming systems in which case vertical reinforcement shall
be No. 4@48 inches on center.
e. Allowable deflection criterion is_L_/240, where_L_ is the unsupported height of the basement wall in inches.
f. Interpolation is not permitted.
g. Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
h. Vertical reinforcement shall be located to provide a cover of 11/4 inches measured from the inside face of the wall. The center of the steel shall not vary from the specified loca-
tion by more than the greater of 10 percent of the wall thickness or3/8 inch.
i. Concrete cover for reinforcement measured from the inside face of the wall shall be not less than3/4 inch. Concrete cover for reinforcement measured from the outside face of
the wall shall be not less than 11/2 inches for No. 5 bars and smaller, and not less than 2 inches for larger bars.
j. DR means design is required in accordance with the applicable building code, or in the absence of a code, in accordance with ACI 318.
k. Concrete shall have a specified compressive strength,f′c, of not less than 2,500 psi at 28 days, unless a higher strength is required by Note l or m.
l. The minimum thickness is permitted to be reduced 2 inches, provided that the minimum specified compressive strength of concrete,f′c, is 4,000 psi.
m.A plain concrete wall with a minimum nominal thickness of 12 inches is permitted, provided that the minimum specified compressive strength of concrete,f′c, is 3,500 psi.
n. See Table R608.3 for tolerance from nominal thickness permitted for flat walls.
o. The use of this table shall be prohibited for soil classifications not shown.|2025 CALIFORNIA RESIDENTIAL CODE 4-35
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TABLE R404.1.3.2(9)—MINIMUM SPACING FOR ALTERNATE BAR SIZE AND ALTERNATE GRADE OF STEELa, b, c Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15 Col16 ** BAR SPACING FROM APPLICABLE**
TABLE IN SECTION R404.1.3.2
(inches)** BAR SIZE FROM APPLICABLE TABLE IN SECTION R404.1.3.2** ** BAR SIZE FROM APPLICABLE TABLE IN SECTION R404.1.3.2** ** BAR SIZE FROM APPLICABLE TABLE IN SECTION R404.1.3.2** ** BAR SIZE FROM APPLICABLE TABLE IN SECTION R404.1.3.2** ** BAR SIZE FROM APPLICABLE TABLE IN SECTION R404. CRC § 2.3.1 Medium relevance — show source text
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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 § 19A-5 Medium relevance — show source text
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CONCRETE
1907 A .2 Nonstructural slabs-on-ground. Nonstructural slabs-on-ground shall be required to comply with Sections 1904 A .2, 1907 A .3 and 1907 A .4. Portions of the nonstructural slabs-on-ground used to resist uplift forces or overturning shall be designed in accordance with accepted engineering practice throughout the entire portion designated as dead load to resist uplift forces or overturning. 1907 A .3 Thickness. The thickness of concrete floor slabs supported directly on the ground shall be not less than 3 [1] / 2 inches (89 mm).
1907 A .4 Vapor retarder. A 6-mil (0.006 inch; 0.15 mm) polyethylene vapor retarder with joints lapped not less than 6 inches (152 mm) shall be placed between the base course or subgrade and the concrete floor slab, or other approved equivalent methods or materials shall be used to retard vapor transmission through the floor slab.
Exception: A vapor retarder is not required:
For detached structures accessory to occupancies in Group R-3, such as garages, utility buildings or other unheated facilities.
For unheated storage rooms having an area of less than 70 square feet (6.5 m [2] ) and carports attached to occupancies in Group R-3.
For buildings of other occupancies where migration of moisture through the slab from below will not be detrimental to the intended occupancy of the building.
For driveways, walks, patios and other flatwork that will not be enclosed at a later date.
Where approved based on local site conditions.
SECTION 1908 A —SHOTCRETE
1908 A .1 General. Shotcrete shall be in accordance with the requirements of ACI 318 and the provisions of ACI 506R. Preconstruction tests of one or more shotcrete mockup panels prepared in accordance with Section 1705A.3.9.2 are required. In addition to testing requirements in ACI 318, special inspection and testing shall be in accordance with Section 1705A.3.9. The evaluation of the shotcrete mockup panel to qualify bar clearance dimensions in accordance with ACI 318 Section 25.2.7 or contact lap splices in accordance with ACI 318 Section 25.5.1.7 shall be in accordance with the requirements of ACI 506.4R with a core quality category of Very Good given in ACI 506.6T.
Shotcrete construction shall be in accordance with the requirements of ACI 506.2.
SECTION 1909A—MODIFICATIONS TO ACI 318
1909A.1 General. The text of ACI 318 shall be modified as indicated in Sections 1909A.1.1 through 1909A.1.16.
1909A.1.1 ACI 318, Section 4.12.2.2. Modify ACI 318, Section 4.12.2.2 by adding the following:
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.
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19 CONCRETE
User notes:
About this chapter: Chapter 19 provides minimum accepted practices for the design and construction of buildings and structural components using concrete—both plain and reinforced. Chapter 19 relies primarily on the reference to American Concrete Institute (ACI) 318, Building Code Requirements for Structural Concrete. Structural concrete must be designed and constructed to comply with this code and all listed standards. There are also specific provisions addressing slabs-on-ground and shotcrete.
This chapter was extensively reorganized for the 2024 edition. For complete information, see the relocations table in the Preface information of this code.
ICC code development note: Code change proposals to this chapter will be considered by the IBC—Structural Code Development Committee during the
2025 (Group B) Code Development Cycle.
SECTION 1901—GENERAL
1901.1 Scope. The provisions of this chapter shall govern the materials, quality control, design and construction of concrete used in structures.
1901.1.1 Application. [DSA-SS/CC, OSHPD] The scope of application of Chapter 19 is as follows: 1. Structures regulated by the Division of the State Architect—Structural Safety/Community Colleges (DSA-SS/CC), which include those applications listed in Section 1.9.2.2. 2. Structures regulated by the Department of Health Care Access and Information/Office of Statewide Hospital Planning and Development (OSHPD), which include hospital buildings removed from general acute care service, skilled nursing facility build- ings, intermediate care facility buildings and acute psychiatric hospital buildings listed in Sections 1.10.1, 1.10.2 and 1.10.5.
1901.1.2 Amendments in this chapter. [DSA-SS/CC, OSHPD] DSA-SS/CC and OSHPD adopts this chapter as amended.
1901.1.3 Identification of amendments. [DSA-SS/CC, OSHPD] 1. Division of the State Architect - Structural Safety/Community Colleges amendments appear in this chapter preceded by the appropriate acronym, as follows:
[DSA-SS/CC] – For applications listed in Section 1.9.2.2. 2. [OSHPD 1R, 2 & 5] Office of Statewide Hospital Planning and Development (OSHPD) amendments appear in this chapter preceded by the appropriate acronym, as follows:
[OSHPD 1R ] – For applications listed in Section 1.10.1.
[OSHPD 2] – For applications listed in Section 1.10.2.
[OSHPD 5] – For applications listed in Section 1.10.5.
CRC § 25.4 Medium relevance — show source text
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
(TYP.)
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FLOORS
SECTION R506—CONCRETE FLOORS (ON GROUND)
R506.1 General. Concrete slab-on-ground floors shall be designed and constructed in accordance with the provisions of this section or ACI 332. Such floors shall be not less than 3 [1] / 2 inches (89 mm) thick (for expansive soils, see Section R403.1.8). The specified compressive strength of concrete shall be as set forth in Section R402.2.
R506.2 Post-tensioned slab-on-ground floors. Post-tensioned concrete slabs-on-ground floors placed on expansive or stable soils shall be designed in accordance with PTI DC10.5.
R506.3 Site preparation. The area within the foundation walls shall have all vegetation, topsoil and foreign material removed.
R506.3.1 Fill. Fill material shall be free of vegetation and foreign material. The fill shall be compacted to ensure uniform support of the slab, and except where approved, the fill depths shall not exceed 24 inches (610 mm) for clean sand or gravel and 8 inches (203 mm) for earth.
R506.3.2 Base. A 4-inch-thick (102 mm) base course consisting of clean graded sand, gravel, crushed stone, crushed concrete or crushed blast-furnace slag passing a 2-inch (51 mm) sieve shall be placed on the prepared subgrade where the slab is below grade.
Exception: A base course is not required where the concrete slab is installed on well-drained or sand-gravel mixture soils classified as Group I according to the United Soil Classification System in accordance with Table R401.4.1(2).
R506.3.3 Vapor retarder. A minimum 6 mil (0.006 inch; 152 μ m) polyethylene or approved vapor retarder with joints lapped not less than 6 inches (152 mm) shall be placed between the concrete floor slab and the base course or the prepared subgrade where a base course does not exist.
Exception: The vapor retarder is not required for the following:
- Garages, utility buildings and other unheated accessory structures.
- For unheated storage rooms having an area of less than 70 square feet (6.5 m [2] ) and carports.
- Driveways, walks, patios and other flatwork not likely to be enclosed and heated at a later date.
- Where approved by the building official, based on local site conditions.
R506.3.3.1 Capillary break. When a vapor retarder is required, a capillary break shall be installed in accordance with the Califor- nia Green Building Standards Code, Chapter 4, Division 4.5.
R506.3.4 Reinforcement support. Where provided in slabs-on-ground, reinforcement shall be supported to remain in place from the center to upper one-third of the slab for the duration of the concrete placement.
SECTION R507—EXTERIOR DECKS
CRC § 3.8 Medium relevance — show source text
Each header joist shall be connected to trimmer joists with four 2-inch by 2-inch (51-mm by 51-mm) clip angles. Each clip angle shall be fastened to both the header and trimmer joists with four No. 8 screws, evenly spaced, through each leg of the clip angle. The clip angles shall have a thickness not less than that of the floor joist. Each track section for a built-up header or trimmer joist shall extend the full length of the joist (continuous).
FIGURE R505.3.8(1)—COLD-FORMED STEEL FLOOR CONSTRUCTION—6-FOOT FLOOR OPENING
JOIST
CLIP ANGLE
For SI: 1 foot = 304.8 mm.
For SI: 1 foot = 304.8 mm.
JOIST
FIGURE R505.3.8(2)—COLD-FORMED STEEL FLOOR CONSTRUCTION—8-FOOT FLOOR OPENING
JOIST
CLIP ANGLE
JOIST
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WITH 4 NO. 8 SCREWS THROUGH EACH LEG, BOTH SIDES OF CONNECTION
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
MINIMUM 2 IN. × 2 IN. CLIP ANGLE
WITH 4 NO. 8 SCREWS THROUGH EACH LEG, BOTH SIDES OF CONNECTION
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
(TYP.)
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FLOORS
SECTION R506—CONCRETE FLOORS (ON GROUND)
R506.1 General. Concrete slab-on-ground floors shall be designed and constructed in accordance with the provisions of this section or ACI 332. Such floors shall be not less than 3 [1] / 2 inches (89 mm) thick (for expansive soils, see Section R403.1.8). The specified compressive strength of concrete shall be as set forth in Section R402.2.
R506.2 Post-tensioned slab-on-ground floors. Post-tensioned concrete slabs-on-ground floors placed on expansive or stable soils shall be designed in accordance with PTI DC10.5.
R506.3 Site preparation. The area within the foundation walls shall have all vegetation, topsoil and foreign material removed.
R506.3.1 Fill. Fill material shall be free of vegetation and foreign material. The fill shall be compacted to ensure uniform support of the slab, and except where approved, the fill depths shall not exceed 24 inches (610 mm) for clean sand or gravel and 8 inches (203 mm) for earth.
R506.3.2 Base. A 4-inch-thick (102 mm) base course consisting of clean graded sand, gravel, crushed stone, crushed concrete or crushed blast-furnace slag passing a 2-inch (51 mm) sieve shall be placed on the prepared subgrade where the slab is below grade.
CRC § 1.3 Medium relevance — show source text
Where an interior concrete slab-on-grade is provided and in contact with the interior surface of the foundation wall, measurement of
the unbalanced backfill height is permitted to be measured from the exterior finish ground level to the top of the interior concrete slab is permitted.
f. The use of this table shall be prohibited for soil classifications not shown.|R404.1.3 Concrete foundation walls. Concrete foundation walls that support light-frame walls shall be designed and constructed in accordance with the provisions of this section, ACI 318, ACI 332 or PCA 100. Concrete foundation walls that support above-grade concrete walls that are within the applicability limits of Section R608.2 shall be designed and constructed in accordance with the provisions of this section, ACI 318, ACI 332 or PCA 100. Concrete foundation walls that support above-grade concrete walls that are not within the applicability limits of Section R608.2 shall be designed and constructed in accordance with the provisions of ACI 318, ACI 332 or PCA 100. Where ACI 318, ACI 332, PCA 100 or the provisions of this section are used to design concrete foundation walls, project drawings, typical details and specifications are not required to bear the seal of the architect or engineer responsible for design, unless otherwise required by the state law of the jurisdiction having authority.
R404.1.3.1 Concrete cross section. Concrete walls constructed in accordance with this code shall comply with the shapes and minimum concrete cross-sectional dimensions required by Table R608.3. Other types of forming systems resulting in concrete walls not in compliance with this section and Table R608.3 shall be designed in accordance with ACI 318.
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R404.1.3.2 Reinforcement for foundation walls. Concrete foundation walls shall be laterally supported at the top and bottom. Horizontal reinforcement shall be provided in accordance with Table R404.1.3.2(1). Vertical reinforcement shall be provided in accordance with Table R404.1.3.2(2), R404.1.3.2(3), R404.1.3.2(4), R404.1.3.2(5), R404.1.3.2(6), R404.1.3.2(7) or R404.1.3.2(8). Vertical reinforcement for flat basement walls retaining 4 feet (1219 mm) or more of unbalanced backfill is permitted to be determined in accordance with Table R404.1.3.2(9). For basement walls supporting above-grade concrete walls, vertical reinforcement shall be the greater of that required by Tables R404.1.3.2(2) through R404.1.3.2(8) or by Section R608.6 for the above-grade wall. In buildings assigned to Seismic Design Category D 0, D 1 or D 2, concrete foundation walls shall also comply with Section R404.1.4.2.
TABLE R404.1.3.2(1)—MINIMUM HORIZONTAL REINFORCEMENT FOR CONCRETE BASEMENT WALLSa, b Col2 ** MAXIMUM UNSUPPORTED**
WALL HEIGHT (feet)** LOCATION OF HORIZONTAL REINFORCEMENT** ≤ 8 One No. CRC § 7.2 Medium relevance — show source text
1905 A .7.2 Anchors in shear. The following exceptions are permitted to ACI 318 Section 17.10.6.2:
Exceptions:
- For the calculation of the in-plane shear strength of anchor bolts attaching wood sill plates of bearing or nonbearing walls of light-frame wood structures to foundations or foundation stemwalls, the in-plane shear strength in accordance with Sections 17.7.2 and 17.7.3 of ACI 318 need not be computed and Section 17.10.6.3 of ACI 318 shall be deemed to be satisfied provided that all of the following are met: 1.1. The allowable in-plane shear strength of the anchor is determined in accordance with ANSI/AWC NDS Table 12E for lateral design values parallel to grain. 1.2. The maximum anchor nominal diameter is [5] / 8 inch (16 mm). 1.3. Anchor bolts are embedded into concrete not less than 7 inches (178 mm). 1.4. Anchor bolts are located not less than 1¾ inches (45 mm) from the edge of the concrete parallel to the length of the wood sill plate. 1.5. Anchor bolts are located not less than 15 anchor diameters from the edge of the concrete perpendicular to the length of the wood sill plate. 1.6. The sill plate is 2-inch (51 mm) or 3-inch (76 mm) nominal thickness.
- For the calculation of the in-plane shear strength of anchor bolts attaching cold-formed steel track of bearing or nonbearing walls of light-frame construction to foundations or foundation stemwalls, the in-plane shear strength in accordance with Sections 17.7.2 and 17.7.3 of ACI 318 need not be computed and Section 17.10.6.3 shall be deemed to be satisfied provided that all of the following are met:
Allowable in-plane shear strength of exempt anchors, parallel to the edge of concrete, shall be permitted to be determined in accordance with AISI S100 Section J3.3.1.
2.1. The maximum anchor nominal diameter is [5] / 8 inch (16 mm). 2.2. Anchors are embedded into concrete a minimum of 7 inches (178 mm). 2.3. Anchors are located a minimum of 1 [3] / 4 inches (45 mm) from the edge of the concrete parallel to the length of the track.
2.4. Anchors are located a minimum of 15 anchor diameters from the edge of the concrete perpendicular to the length of the track. 2.5. The track is 33 to 68 mil (0.84 mm to 1.73 mm) designation thickness. 3. In light-frame construction bearing or nonbearing walls, shear strength of concrete anchors less than or equal to 1 inch (25 mm) in diameter attaching sill plate or track to foundation or foundation stemwalls need not satisfy Sections 17.10.6.3(a) through (c) when the design strength of the anchors is determined in accordance with Section 17.7.2.1(c) of ACI 318.
SECTION 1906 A — RESERVED
SECTION 1907 A —SLABS-ON-GROUND
CRC § 1.1 Medium relevance — show source text
1.1_|||||||||X||X|X|||X|||||||||| |1901.1.2|||||||||X||X|X|||X|||||||||| |1901.1.3|||||||||X||X|X|||X|||||||||| |1901.1.4|||||||||X|||||||||||||||| |1901.1.5|||||||||X|||||||||||||||| |1901.3.1 – 1901.3.4.5|||||||||||X|X|||X|||||||||| |1903.1|||||||||||X|X|||X|||||||||| |1903.3|||||||||||X|X|||X|||||||||| |1903.4|||||||||||X|X|||X|||||||||| |1903.5|||||||||||X|X|||X|||||||||| |1905.1.8||||||||||||||||||||||||| |1905.5|||||||||||X|X|||X|||||||||| |1905.6|||||||||||X|X|||X|||||||||| |1906|||||||||||X|X|||X|||||||||| |1907.4.1||||X||||||||||||||||||||| |1908.1|||||||||||X|X|||X|||||||||| |1909|||||||||X|||||||||||||||| |1910|||||||||||X|X|||X|||||||||| |1911|||||||||||X|X|||X||||||||||
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.
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19 CONCRETE
User notes:
About this chapter: Chapter 19 provides minimum accepted practices for the design and construction of buildings and structural components using concrete—both plain and reinforced. Chapter 19 relies primarily on the reference to American Concrete Institute (ACI) 318, Building Code Requirements for Structural Concrete. Structural concrete must be designed and constructed to comply with this code and all listed standards. There are also specific provisions addressing slabs-on-ground and shotcrete.
This chapter was extensively reorganized for the 2024 edition. For complete information, see the relocations table in the Preface information of this code.
ICC code development note: Code change proposals to this chapter will be considered by the IBC—Structural Code Development Committee during the
2025 (Group B) Code Development Cycle.
SECTION 1901—GENERAL
1901.1 Scope. The provisions of this chapter shall govern the materials, quality control, design and construction of concrete used in structures.
CRC § 4.1.1.4 Medium relevance — show source text
R401.4.1.1.4 Liability. A city, county, or city and county or other enforcement agency charged with the administration and enforcement of the provisions of Section R401.4.1.1, is not liable for any injury which arises out of any act or omission of the city, county or city and county, or other enforcement agency, or a public employee or any other person under Section R401.4.1.1.1, R401.4.1.1.2 or R401.4.1.1.3.
R401.4.1.1.5 Alternate procedures. The governing body of any city, county, or city and county may enact an ordinance prescribing an alternate procedure which is equal to or more restrictive than the procedures specified in Sections R401.4.1.1.1, R401.4.1.1.2 and R401.1.1.3.
R401.4.2 Compressible or shifting soil. Instead of a complete geotechnical evaluation, where top or subsoils are compressible or shifting, they shall be removed to a depth and width sufficient to ensure stable moisture content in each active zone and shall not be used as fill or stabilized within each active zone by chemical, dewatering or presaturation.
SECTION R402—MATERIALS
R402.1 Wood foundations. Wood foundation systems shall be designed and installed in accordance with the provisions of this code.
R402.1.1 Fasteners. Fasteners used below grade to attach plywood to the exterior side of exterior basement or crawl-space wall studs, or fasteners used in knee wall construction, shall be of Type 304 or 316 stainless steel. Fasteners used above grade to attach plywood and all lumber-to-lumber fasteners except those used in knee wall construction shall be of Type 304 or 316 stainless steel, silicon bronze, copper, hot-dipped galvanized (zinc coated) steel nails, or hot-tumbled galvanized (zinc coated) steel nails. Electro-galvanized steel nails and galvanized (zinc coated) steel staples shall not be permitted.
R402.1.2 Wood treatment. Lumber and plywood shall be pressure-preservative treated and dried after treatment in accordance with AWPA U1 (Commodity Specification A, Special Requirement 4.2), and shall bear the label of an accredited agency. Where lumber or plywood is cut or drilled after treatment, the treated surface shall be field treated with copper naphthenate, the concentration of which shall contain not less than 2-percent copper metal, by repeated brushing, dipping or soaking until the wood cannot absorb more preservative.
R402.2 Concrete. Concrete shall have a minimum specified compressive strength of f′ c, as shown in Table R402.2. Concrete subject to moderate or severe weathering as indicated in Table R301.2 shall be air entrained as specified in Table R402.2. The maximum weight of fly ash, other pozzolans, silica fume, slag or blended cements that is included in concrete mixtures for garage floor slabs and for exterior porches, carport slabs and steps that will be exposed to deicing chemicals shall not exceed the percentages of the total weight of cementitious materials specified in Section 19.3.3.4 of ACI 318. Materials used to produce concrete and testing thereof shall comply with the applicable standards listed in Chapters 19 and 20 of ACI 318 or ACI 332.
|TABLE R402.
CRC § 25.4 Medium relevance — show source text
Installation of all adhesive anchors in horizontal and upwardly inclined positions shall be performed by an ACI/CRSI Certified Adhesive Anchor Installer, except where the factored_
design tension on the anchors is less than 100 pounds and those anchors are clearly noted on the approved construction documents or where the anchors are shear dowels across
cold joints in slabs on grade where the slab is not part of the lateral force-resisting system.|For SI: 1 inch = 25.4 mm.
a. Where applicable, see Section 1705_A_.13.
b. Specific requirements for special inspection shall be included in the research report for the anchor issued by an approved source in accordance with 26.13 in ACI 318, or other
qualification procedures. Where specific requirements are not provided, special inspection requirements shall be specified by the registered design professional and shall be
approved by the building official prior to the commencement of the work.
c. Installation of all adhesive anchors in horizontal and upwardly inclined positions shall be performed by an ACI/CRSI Certified Adhesive Anchor Installer, except where the factored
design tension on the anchors is less than 100 pounds and those anchors are clearly noted on the approved construction documents or where the anchors are shear dowels across
cold joints in slabs on grade where the slab is not part of the lateral force-resisting system.|1705 A .3.1 Welding of reinforcing bars. Special inspections of welding and qualifications of special inspectors for reinforcing bars shall be in accordance with Section 1705A.2.7, the requirements of AWS D1.4 for special inspection and of AWS D1.4 for special inspector qualification.
1705 A .3.2 Material tests. In the absence of sufficient data or documentation providing evidence of conformance to quality standards for materials in Chapters 19, 20 and 26 of ACI 318, as modified by Chapter 19A, the building official shall require testing of materials in accordance with the appropriate standards and criteria for the material in Chapters 19, 20 and 26 of ACI 318 as modi- fied by Chapter 19A. Cementitious materials shall be in accordance with 1910A.1 ([DSA-SS/CC] 1909.2.3). Tests of reinforcing bars shall be in accordance with Section 1910A.2 ( [DSA-SS/CC] 1909.2.4).
1705A.3.3 Batch plant inspection. Except as provided under this section, the quality and quantity of materials used in transit-mixed concrete and in batched aggregates shall be continuously inspected by an approved agency at the location where materials are measured.
[DSA-SS, DSA-SS/CC] The minimum requirements for a qualified batch plant inspector shall be possession of either: 1. Both of the following: a. A valid certification from ACI as a Concrete Field or Lab Testing Technician.
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SPECIAL INSPECTIONS AND TESTS
b. Approved agency documented training records of batch plant inspection and California Administrative Code requirements. 2. A valid California Civil Engineering license.
_**1705A.3.3.1 Waiver of continuous batch plant inspection.
Frequently asked questions
Which ACI standard should I use for a typical residential interior slab‑on‑grade?
Use ACI 332 for design and construction of residential slabs-on-ground where the CRC permits it; confirm slab thickness and f′c per § R506.1 and § R402.2.
Does the CRC ever require ACI 318 instead of ACI 332?
Yes — for general structural concrete provisions and where the CRC explicitly references ACI 318 for materials, testing or where applicability exceeds ACI 332’s residential limits (see § R402.2 and the referenced-standards list).
Can I design foundation walls to PCA guidance instead of ACI?
Yes — § R404.1.3 permits foundation walls supporting light‑frame walls to be designed using ACI 318, ACI 332 or PCA 100. Check the section text for any limits and local seal requirements.
Where do I find the required compressive strength (f′c) for my slab or footing?
The CRC sets the required compressive strength values in Table R402.2; § R402.2 directs you to that table. Consult the CRC table directly for the numeric psi values.
Are post‑tensioned slabs covered by ACI 332 in the CRC?
No — § R506.2 requires post‑tensioned slab‑on‑ground floors to be designed in accordance with PTI DC10.5.
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