CRC · California Residential Code

What minimum footing widths/thicknesses apply for light‑frame construction?

Q: Can I interpolate between soil bearing values in the table?

Yes — the table notes permit linear interpolation between listed soil bearing values. Do not extrapolate beyond the table values.

Q: Are there separate rules for brick veneer or CMU walls?

Yes. CRC provides separate prescriptive tables for light‑frame with brick veneer (Table R403.1(2)) and for cast‑in‑place concrete or partially grouted masonry (Table R403.1(3)). Use the table that matches your wall assembly.

For a typical light‑frame house you pick the footing size from the CRC’s R403.1 tables based on your wall type, number of stories and soil bearing capacity; but regardless of the table you must meet the absolute minimum of 12 inches wide by 6 inches thick and follow the table notes (interpolate only, adjust for building width) — see § R403.1 and § R403.1.1.

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

The California Residential Code requires that footings for light‑frame construction meet the minimum widths and thicknesses shown in the prescriptive tables in § R403.1 (Tables R403.1(1)–(3)), with an absolute minimum width of 12 inches and minimum thickness of 6 inches for concrete footings. The footing width must be selected based on the load‑bearing value of the soil and the type/number of stories; additional notes to the tables permit limited interpolation and adjustments for building width. See § R403.1 and § R403.1.1 for the controlling requirements.

The single most important rule: choose the footing width from the applicable R403.1 table for your building type and soil bearing capacity, but never less than 12 in. wide and 6 in. thick.

Requirements in detail

Key definitions (first mention bolded)

Footing width (W) — horizontal dimension of the footing required to distribute wall loads to soil. § R403.1.
Footing thickness (T) — vertical depth (edge or overall as applicable) of the footing. § R403.1.1.
Load‑bearing value of the soil — the allowable bearing capacity used to select table values (see referral in § R403.1.1).

Where to read the tables

Use Table R403.1(1) for typical light‑frame exterior wall footings; there are alternate tables for footings supporting brick veneer (Table R403.1(2)) and for CMU/concrete wall construction (Table R403.1(3)). All are part of § R403.1.

Hard numeric minimums and table rules

Absolute minimums: 12 in. width and 6 in. depth/thickness for concrete footings (unless a specific table entry requires more). § R403.1.1.
Footing projection beyond the wall (P) must be not less than 2 in. and not greater than the thickness of the footing. § R403.1.1.
Footing width selection is based on the building/story type and the load‑bearing value of the soil per the table heading and notes. § R403.1 and § R403.1.1.
Table notes allow linear interpolation between listed soil bearing values but do not permit extrapolation beyond the table ranges. Table notes.

Decision‑relevant dimensions (quick reference table)

Condition / common case	Typical required W × T (in.)	Code reference
1‑story light‑frame, slab‑on‑grade (all listed soils 1,500–4,000 psf)	12 × 6	§ R403.1 Table R403.1(1)
1‑story light‑frame with basement, 1,500 psf soil	16 × 6	§ R403.1 Table R403.1(1)
Prescriptive (alternate reference) — walls supporting 1, 2 or 3 floors (CBC prescriptive)	1 floor: 12 × 6; 2 floors: 15 × 6; 3 floors: 18 × 8	See CBC Table 1809.7 (useful comparison)
Absolute minimum (regardless of table)	W ≥ 12 in., T ≥ 6 in.	§ R403.1.1

(Notes: the CRC provides separate tables for brick veneer and for CMU/concrete wall construction; use the table that matches your wall assembly and the soil bearing capacity shown in the table headings.)

Exceptions & special cases

Where the building width perpendicular to the wall footing differs from the table’s assumed 32 ft, you must adjust footing size: increase width by 2 in. and depth by 1 in. for every 4 ft of building width increase; conversely, you may reduce by the same increments down to the minimums. These adjustment rules are table notes.
Footings supporting fireplaces follow separate thickness/projection rules in § R1001.2 (referenced by § R403.1.1).
Footings for wood (permanent) foundations, precast foundations, or crushed‑stone footings are covered in Sections R403.2, R403.4, and R403.5 respectively; those sections include additional details and companion figures.
The prescriptive CRC tables are calibrated to specific load and building assumptions (see table notes). If your loads, widths, or soil conditions fall outside those assumptions, the tables may not apply and engineered design is required.

Common mistakes

Relying on interpolation beyond the table range (extrapolation) — the table notes explicitly prohibit extrapolation.
Using the wrong table for the wall type (e.g., using the “light‑frame with brick veneer” table when the wall is CMU or cast‑in‑place concrete). Always confirm which R403.1 table applies.
Forgetting the absolute minimums: even if a calculation suggests a smaller footing, do not go below 12 in. × 6 in. unless another code allowance explicitly permits it. § R403.1.1.
Mixing prescriptive tables from the CBC (Table 1809.7) with CRC tables without checking which code applies to your project; the CRC tables and CBC prescriptive tables may be similar but are presented in different chapters and contexts.

Worked example — concrete scenario applying the rule with numbers

Scenario: A detached, single‑story light‑frame house on a normal slab‑on‑grade foundation. Soil bearing test indicates 2,500 psf allowable bearing. Roof live load assumed per CRC table (20 psf roof live or 25 psf ground snow).

Which table? Use Table R403.1(1) for light‑frame exterior wall footings. § R403.1.
Table entry for 1‑story — slab‑on‑grade shows 12 × 6 (this entry applies across the soil bearing values listed in the table for the stated live load). Therefore the minimum footing required by the prescriptive table is 12 inches wide × 6 inches thick. § R403.1 Table R403.1(1).
Check minimums: the table result equals the absolute minimums of W = 12 in., T = 6 in., so no further adjustment is required. § R403.1.1.

If the building width perpendicular to the footing were greater than the table assumption (32 ft), you would increase the footing width 2 in. and depth 1 in. for every additional 4 ft of building width (table note).

Related provisions (CRC sections)

§ R403.1 — General footing requirements and the prescriptive footing tables (R403.1(1)–(3)).
§ R403.1.1 — Minimum size: restates the 12 in. × 6 in. minimums and projection rules.
§ R403.1.2 — Continuous footing requirements in specified Seismic Design Categories (D0, D1, D2).
§ R403.2 — Footings for wood foundations (details and figures).
§ R403.4 — Precast foundation footings (details and table cross‑references).
§ R403.5 — Crushed‑stone footings for cast‑in‑place foundations.
§ R401.4.1(1) — Table referenced for allowable soil bearing values used to pick footing widths.

Code references

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

CRC § 4-7 High relevance — show source text

Linear interpolation of footing width is permitted between the soil bearing pressures in the table. Extrapolation is not permitted.
b. The table is based on the following conditions and loads: building width, 32 feet; wall height, 9 feet; basement wall height, 8 feet; dead loads, 15 psf roof and ceiling assembly,
10 psf floor assembly, 12 psf wall assembly; live loads, roof and ground snow loads as listed, 40 psf first floor, 30 psf second and third floors. Footing sizes are calculated
assuming a clear span roof/ceiling assembly and an interior bearing wall or beam at each floor.
c. Where the building width perpendicular to the wall footing is greater than 32 feet, the footing width shall be increased by 2 inches and footing depth shall be increased by 1
inch for every 4 feet of increase in building width.
d. Where the building width perpendicular to the wall footing is less than 32 feet, a 2-inch decrease in footing width and 1-inch decrease in footing depth is permitted for every 4
feet of decrease in building width provided that the minimum width is 12 inches and minimum depth is 6 inches.
SLAB
ON GRADE
BASEMENT
CRAWL
SPACE|

2025 CALIFORNIA RESIDENTIAL CODE 4-7

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FOUNDATIONS

TABLE R403.1(2)—MINIMUM WIDTH AND THICKNESS FOR CONCRETE FOOTINGS FOR LIGHT-FRAME CONSTRUCTION WITH BRICK VENEER OR LATH AND PLASTER (inches)a, b, c, d	Col2	Col3	Col4	Col5	Col6	Col7	Col8
GROUND SNOW LOAD OR ROOF LIVE LOAD	STORY AND TYPE OF STRUCTURE WITH BRICK VENEER	LOAD-BEARING VALUE OF SOIL (psf)	LOAD-BEARING VALUE OF SOIL (psf)	LOAD-BEARING VALUE OF SOIL (psf)	LOAD-BEARING VALUE OF SOIL (psf)	LOAD-BEARING VALUE OF SOIL (psf)	LOAD-BEARING VALUE OF SOIL (psf)
GROUND SNOW LOAD OR ROOF LIVE LOAD	STORY AND TYPE OF STRUCTURE WITH BRICK VENEER	1,500	2,000	2,500	3,000	3,500	4,000
20 psf roof live load or 25 psf ground snow load	1 story—slab-on-grade	12 × 6	12 × 6	12 × 6	12 × 6	12 × 6	12 × 6
20 psf roof live load or 25 psf ground snow load	1 story—with crawl space	15 × 6	12 × 6	12 × 6	12 × 6	12 × 6	12 × 6
20 psf roof live load or 25 psf ground snow load	1 story—plus basement	18 × 6	14 × 6	12 ×

CRC § 1809.7 High relevance — show source text

TABLE 1809.7—PRESCRIPTIVE FOOTINGS SUPPORTING WALLS OF LIGHT-FRAME CONSTRUCTIONa, b, c, d, e	Col2	Col3
NUMBER OF FLOORS SUPPORTED BY THE FOOTINGf	WIDTH OF FOOTING (inches)	THICKNESS OF FOOTING (inches)
1	12	6
2	15	6
3	18	8g
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm. a. Depth of footings shall be in accordance with Section 1809.4. b. The ground under the floor shall be permitted to be excavated to the elevation of the top of the footing. c. Interior stud-bearing walls shall be permitted to be supported by isolated footings. The footing width and length shall be twice the width shown in this table, and footings shall be spaced not more than 6 feet on center. d. See Section 1905 for additional requirements for concrete footings of structures assigned to Seismic Design Category C, D, E or F. e. For thickness of foundation walls, see Section 1807.1.6. f. Footings shall be permitted to support a roof in addition to the stipulated number of floors. Footings supporting roof only shall be as required for supporting one floor. g. Plain concrete footings for Group R-3 occupancies shall be permitted to be 6 inches thick.	For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm. a. Depth of footings shall be in accordance with Section 1809.4. b. The ground under the floor shall be permitted to be excavated to the elevation of the top of the footing. c. Interior stud-bearing walls shall be permitted to be supported by isolated footings. The footing width and length shall be twice the width shown in this table, and footings shall be spaced not more than 6 feet on center. d. See Section 1905 for additional requirements for concrete footings of structures assigned to Seismic Design Category C, D, E or F. e. For thickness of foundation walls, see Section 1807.1.6. f. Footings shall be permitted to support a roof in addition to the stipulated number of floors. Footings supporting roof only shall be as required for supporting one floor. g. Plain concrete footings for Group R-3 occupancies shall be permitted to be 6 inches thick.	For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm. a. Depth of footings shall be in accordance with Section 1809.4. b. The ground under the floor shall be permitted to be excavated to the elevation of the top of the footing. c. Interior stud-bearing walls shall be permitted to be supported by isolated footings. The footing width and length shall be twice the width shown in this table, and footings shall be spaced not more than 6 feet on center. d. See Section 1905 for additional requirements for concrete footings of structures assigned to Seismic Design Category C, D, E or F. e. For thickness of foundation walls, see Section 1807.1.6. f. Footings shall be permitted to support a roof in addition to the stipulated number of floors. Footings supporting roof only shall be as required for supporting one floor. g.

CRC § 2-800 High relevance — show source text
—|—| |2-800S162-43|—|—|—|—|—|—|—|—|—|—| |2-800S162-54|4′-3″|3′-5″|2′-8″|—|—|3′-9″|3′-0″|2′-3″|—|—| |2-800S162-68|5′-8″|4′-11″|4′-2″|3′-7″|2′-11″|5′-3″|4′-6″|3′-10″|3′-3″|2′-7″| |2-1000S162-43|—|—|—|—|—|—|—|—|—|—| |2-1000S162-54|4′-8″|3′-11″|3′-1″|2′-2″|—|4′-3″|3′-5″|2′-7″|—|—| |2-1000S162-68|6′-5″|5′-7″|4′-9″|4′-1″|3′-4″|5′-11″|5′-1″|4′-5″|3′-8″|2′-11″| |2-1200S162-54|3′-11″|3′-5″|3′-0″|2′-4″|—|3′-7″|3′-2″|2′-10″|—|—| |2-1200S162-68|7′-1″|6′-2″|5′-3″|4′-6″|3′-8″|6′-6″|5′-8″|4′-10″|4′-0″|3′-3″| |For SI: 1 mil = 0.0254 mm, 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa, 1 ksi = 1,000 psi = 6.895 MPa.
a. Deflection criteria:L/360 for live loads,L/240 for total loads.
b. Design load assumptions:
Second-floor dead load is 10 psf.
Roof/ceiling dead load is 12 psf.
Second-floor live load is 40 psf.
Third floor live load is 30 psf.
Attic live load is 10 psf.
c. Building width is in the direction of horizontal framing members supported by the header.
d. Minimum Grade 33 ksi steel shall be used for 33 mil and 43 mil thicknesses.
CRC § 1807.1.6. High relevance — show source text
Interior stud-bearing walls shall be permitted to be supported by isolated footings. The footing width and length shall be twice the width shown in this table, and footings
shall be spaced not more than 6 feet on center.
d. See Section 1905 for additional requirements for concrete footings of structures assigned to Seismic Design Category C, D, E or F.
e. For thickness of foundation walls, see Section 1807.1.6.
f. Footings shall be permitted to support a roof in addition to the stipulated number of floors. Footings supporting roof only shall be as required for supporting one floor.
g. Plain concrete footings for Group R-3 occupancies shall be permitted to be 6 inches thick.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
a. Depth of footings shall be in accordance with Section 1809.4.
b. The ground under the floor shall be permitted to be excavated to the elevation of the top of the footing.
c. Interior stud-bearing walls shall be permitted to be supported by isolated footings. The footing width and length shall be twice the width shown in this table, and footings
shall be spaced not more than 6 feet on center.
d. See Section 1905 for additional requirements for concrete footings of structures assigned to Seismic Design Category C, D, E or F.
e. For thickness of foundation walls, see Section 1807.1.6.
f. Footings shall be permitted to support a roof in addition to the stipulated number of floors. Footings supporting roof only shall be as required for supporting one floor.
g. Plain concrete footings for Group R-3 occupancies shall be permitted to be 6 inches thick.|

1809.8 Plain concrete footings. [OSHPD 1R, 2 & 5] Not permitted by OSHPD. The edge thickness of plain concrete footings supporting walls of other than light-frame construction shall be not less than 8 inches (203 mm) where placed on soil or rock.

Exception: For plain concrete footings supporting Group R-3 occupancies, the edge thickness is permitted to be 6 inches (152 mm), provided that the footing does not extend beyond a distance greater than the thickness of the footing on either side of the supported wall.

1809.9 Masonry-unit footings. [OSHPD 1R, 2 & 5] Not permitted by OSHPD. The design, materials and construction of masonry-unit footings shall comply with Sections 1809.9.1 and 1809.9.2, and the provisions of Chapter 21.

Exception: Where a specific design is not provided, masonry-unit footings supporting walls of light-frame construction shall be permitted to be designed in accordance with Table 1809.7.

1809.9.1 Dimensions. Masonry-unit footings shall be laid in Type M or S mortar complying with Section 2103.2.1 and the depth shall be not less than twice the projection beyond the wall, pier or column. The width shall be not less than 8 inches (203 mm) wider than the wall supported thereon. 1809.9.2 Offsets. The maximum offset of each course in brick foundation walls stepped up from the footings shall be 1 [1] / 2 inches (38 mm) where laid in single courses, and 3 inches (76 mm) where laid in double courses.
CRC § 2.3 High relevance — show source text
2 � 6 IN. STUD INSULATED

AS APPROPRIATE AND WARM SIDE

VAPOR BARRIER

FINISH GRADE SLOPE [1] / 2 IN. PER FOOT, MIN. 6 FT. FROM WALL

PRESSURE-PRESERVATIVETREATED PLYWOOD (SEE TABLE R404.2.3)

6 MIL POLYETHYLENE FILM

6 MIL POLYETHYLENE FILM ON CRUSHED STONE OR GRAVEL BACKFILL

PRESSURE-PRESERVATIVE TREATED 2 � 6 IN. BOTTOM

Col1 2-IN. AIR GAP

. BACKFILL) 2-IN. AIR GAP
4 IN.
1-IN.-THICK PRESSURE
TREATED LUMBER OR
PROTECTING TOP OF P
PRESS
TREAT
PLATE
PRES
TREA
PLATE
.

HED
4 IN.
16 IN HED
4 IN.
16 IN

STONE FILL UNDER FLOOR (SEE SECTION R403.2)

6 IN.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mil = 0.0254 mm.

FIGURE R403.1(3)—PERMANENT WOOD FOUNDATION CRAWL SPACE SECTION

PRESSURE-PRESERVATIVE TREATED

6 MIL POLYETHYLENE FILM

6 IN.

6 IN. GRAVEL OR CRUSHED STONE (SEE SECTION R403.2)

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mil = 0.0254 mm.

FINISH GRADE SLOPE [1] / 2 IN. PER FOOT, MIN. 6 FT. FROM WALL

16 IN.

PRESSURE-PRESERVATIVE TREATED 2 � 6 IN. STUD WALL

PRESSURE-PRESERVATIVE TREATED PLYWOOD (SEE TABLE R404.2.3)

PRESSURE-PRESERVATIVE TREATED 2 � 6 IN. BOTTOM PLATE

PRESSURE-PRESERVATIVE TREATED 2 � 8 IN. FOOTING PLATE

BELOW FROST LINE

2025 CALIFORNIA RESIDENTIAL CODE 4-11

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FOUNDATIONS

R403.1.1 Minimum size. The minimum width, W, and thickness, T, for concrete footings shall be in accordance with Tables R403.1(1) through R403.1(3) and Figure R403.1(1) or R403.1.3, as applicable, but not less than 12 inches (305 mm) in width and 6 inches (152 mm) in depth. The footing width shall be based on the load-bearing value of the soil in accordance with Table R401.4.1(1). Footing projections, P, shall be not less than 2 inches (51 mm) and shall not exceed the thickness of the footing. Footing thickness and projection for fireplaces shall be in accordance with Section R1001.2. The size of footings supporting piers and columns shall be based on the tributary load and allowable soil pressure in accordance with Table R401.4.1(1).

Col1	2-IN. AIR GAP
. BACKFILL)	2-IN. AIR GAP 4 IN. 1-IN.-THICK PRESSURE TREATED LUMBER OR PROTECTING TOP OF P PRESS TREAT PLATE PRES TREA PLATE .
HED 4 IN. 16 IN	HED 4 IN. 16 IN

CRC § 2.3 High relevance — show source text

FINISH GRADE SLOPE [1] / 2 IN. PER FOOT, MIN. 6 FT. FROM WALL

16 IN.

PRESSURE-PRESERVATIVE TREATED 2 � 6 IN. STUD WALL

PRESSURE-PRESERVATIVE TREATED PLYWOOD (SEE TABLE R404.2.3)

PRESSURE-PRESERVATIVE TREATED 2 � 6 IN. BOTTOM PLATE

PRESSURE-PRESERVATIVE TREATED 2 � 8 IN. FOOTING PLATE

BELOW FROST LINE

2025 CALIFORNIA RESIDENTIAL CODE 4-11

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FOUNDATIONS

R403.1.1 Minimum size. The minimum width, W, and thickness, T, for concrete footings shall be in accordance with Tables R403.1(1) through R403.1(3) and Figure R403.1(1) or R403.1.3, as applicable, but not less than 12 inches (305 mm) in width and 6 inches (152 mm) in depth. The footing width shall be based on the load-bearing value of the soil in accordance with Table R401.4.1(1). Footing projections, P, shall be not less than 2 inches (51 mm) and shall not exceed the thickness of the footing. Footing thickness and projection for fireplaces shall be in accordance with Section R1001.2. The size of footings supporting piers and columns shall be based on the tributary load and allowable soil pressure in accordance with Table R401.4.1(1). Footings for wood foundations shall be in accordance with the details set forth in Section R403.2, and Figures R403.1(2) and R403.1(3). Footings for precast foundations shall be in accordance with the details set forth in Section R403.4, Table R403.4, and Figures R403.4(1) and R403.4(2). Crushed stone footings for cast-in-place concrete foundations shall be in accordance with Section R403.5.

R403.1.2 Continuous footing in Seismic Design Categories D 0 , D 1 and D 2 . Exterior walls and required interior braced wall panels of buildings located in Seismic Design Categories D 0, D 1 and D 2 shall be supported by continuous solid or fully grouted masonry or concrete footings in accordance with Table R403.1.2. Other footing materials or systems shall be designed in accordance with accepted engineering practice.

TABLE R403.1.2—CONTINUOUS FOOTING REQUIREMENTS IN SEISMIC DESIGN CATEGORIES D, D AND D 0 1 2	Col2	Col3	Col4	Col5	Col6	Col7	Col8	Col9	Col10	Col11	Col12	Col13	Col14	Col15
**BUILDING PLAN

CRC § 1809.8 High relevance — show source text
1809.8 Plain concrete footings. [OSHPD 1R, 2 & 5] Not permitted by OSHPD. The edge thickness of plain concrete footings supporting walls of other than light-frame construction shall be not less than 8 inches (203 mm) where placed on soil or rock.

Exception: For plain concrete footings supporting Group R-3 occupancies, the edge thickness is permitted to be 6 inches (152 mm), provided that the footing does not extend beyond a distance greater than the thickness of the footing on either side of the supported wall.

1809.9 Masonry-unit footings. [OSHPD 1R, 2 & 5] Not permitted by OSHPD. The design, materials and construction of masonry-unit footings shall comply with Sections 1809.9.1 and 1809.9.2, and the provisions of Chapter 21.

Exception: Where a specific design is not provided, masonry-unit footings supporting walls of light-frame construction shall be permitted to be designed in accordance with Table 1809.7.

1809.9.1 Dimensions. Masonry-unit footings shall be laid in Type M or S mortar complying with Section 2103.2.1 and the depth shall be not less than twice the projection beyond the wall, pier or column. The width shall be not less than 8 inches (203 mm) wider than the wall supported thereon. 1809.9.2 Offsets. The maximum offset of each course in brick foundation walls stepped up from the footings shall be 1 [1] / 2 inches (38 mm) where laid in single courses, and 3 inches (76 mm) where laid in double courses.

2025 CALIFORNIA BUILDING CODE 18-19

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SOILS AND FOUNDATIONS

1809.10 Pier and curtain wall foundations. Except in Seismic Design Categories D, E and F, pier and curtain wall foundations shall be permitted to be used to support light-frame construction not more than two stories above grade plane, provided that the following requirements are met:
1. All load-bearing walls shall be placed on continuous concrete footings bonded integrally with the exterior wall footings.
2. The minimum actual thickness of a load-bearing masonry wall shall be not less than 4 inches (102 mm) nominal or 3 [5] / 8 inches (92 mm) actual thickness, and shall be bonded integrally with piers spaced 6 feet (1829 mm) on center (o.c.).
3. Piers shall be constructed in accordance with Chapter 21 and the following: 3.1. The unsupported height of the masonry piers shall not exceed 10 times their least dimension. 3.2. Where structural clay tile or hollow concrete masonry units are used for piers supporting beams and girders, the cellular spaces shall be filled solidly with concrete or Type M or S mortar. Exception: Unfilled hollow piers shall be permitted where the unsupported height of the pier is not more than four times its least dimension.

CRC § 1809.5 High relevance — show source text

1809.5 Frost protection. Except where otherwise protected from frost, foundations and other permanent supports of buildings and structures shall be protected from frost by one or more of the following methods:

Extending below the frost line of the locality.
Constructing in accordance with ASCE 32.
Erecting on solid rock.

Exception: Free-standing buildings meeting all of the following conditions shall not be required to be protected:

Assigned to Risk Category I.
Area of 600 square feet (56 m [2] ) or less for light-frame construction or 400 square feet (37 m [2] ) or less for other than lightframe construction.
Eave height of 10 feet (3048 mm) or less.

Shallow foundations shall not bear on frozen soil unless such frozen condition is of a permanent character.

1809.5.1 Frost protection at required exits. Frost protection shall be provided at exterior landings for all required exits with outward-swinging doors. Frost protection shall only be required to the extent necessary to ensure the unobstructed opening of the required exit doors.

1809.6 Location of footings. Footings on granular soil shall be so located that the line drawn between the lower edges of adjacent footings shall not have a slope steeper than 30 degrees (0.52 rad) with the horizontal, unless the material supporting the higher footing is braced or retained or otherwise laterally supported in an approved manner or a greater slope has been properly established by engineering analysis.

1809.7 Prescriptive footings for light-frame construction. [OSHPD 1R, 2 & 5] Not permitted by OSHPD. Where a specific design is not provided, concrete or masonry-unit footings supporting walls of light-frame construction shall be permitted to be designed in accordance with Table 1809.7.

TABLE 1809.7—PRESCRIPTIVE FOOTINGS SUPPORTING WALLS OF LIGHT-FRAME CONSTRUCTIONa, b, c, d, e	Col2	Col3
NUMBER OF FLOORS SUPPORTED BY THE FOOTINGf	WIDTH OF FOOTING (inches)	THICKNESS OF FOOTING (inches)
1	12	6
2	15	6
3	18	8g
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm. a. Depth of footings shall be in accordance with Section 1809.4. b. The ground under the floor shall be permitted to be excavated to the elevation of the top of the footing. c. Interior stud-bearing walls shall be permitted to be supported by isolated footings. The footing width and length shall be twice the width shown in this table, and footings shall be spaced not more than 6 feet on center. d. See Section 1905 for additional requirements for concrete footings of structures assigned to Seismic Design Category C, D, E or F. e. For thickness of foundation walls, see Section 1807.1.6. f. Footings shall be permitted to support a roof in addition to the stipulated number of floors. Footings supporting roof only shall be as required for supporting one floor. g. Plain concrete footings for Group R-3 occupancies shall be permitted to be 6 inches thick.	For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm. a.

CRC § 8.8 High relevance — show source text
**
HOURS| |ITEM CODE|DEPTH|CONSTRUCTION DETAILS|LOAD|TIME|PRE-BMS-92|BMS-92|POST-BMS-92|POST-BMS-92|POST-BMS-92| |B-11-RC-1|11″|24″ wide × 11″ deep reinforced concrete “T”
beam (3290 psi); details: see Note 5 figure.|8.8 tons|4 hrs
2 min|||7|1, 2, 14|4| |B-10-RC-2|10″|24″ wide × 10″ deep reinforced concrete “T”
beam (4370 psi); details: see Note 6 figure.|8.8 tons|1 hr
53
min|||7|1, 3|13/4| |B-10-RC-3|101/2″|24″ wide × 101/2″ deep reinforced concrete
“T” beam (4450 psi); details: see Note 7
figure.|8.8 tons|2 hrs
40
min|||7|1, 3|22/3| |B-11-RC-4|11″|24″ wide × 11″ deep reinforced concrete “T”
beam (2400 psi); details: see Note 8 figure.|8.8 tons|3 hrs
32
min|||7|1, 3, 14|31/2| |B-11-RC-5|11″|24″ wide × 11″ deep reinforced concrete “T”
beam (4250 psi); details: see Note 9 figure.|8.8 tons|3 hrs
3 min|||7|1, 3, 14|3| |B-11-RC-6|11″|Concrete flange: 4″ deep × 2' wide (4895 psi)
concrete; concrete beam: 7″ deep × 61/2″
wide; “I” beam reinforcement; 10″ × 41/2″ ×
25 lbs R.S.J.; 1″ cover on flanges; flange rein-
forcement:3/8″ diameter bars at 6″ pitch
parallel to “T”; 1/4″ diameter bars perpendic-
ular to “T”; beam reinforcement: 4″ × 6″ No.
13 SWG wire mesh; span: 11' restrained;
details: see Note 10 figure.|10 tons|6 hrs|||7|1, 4|6| |B-11-RC-7|11″|Concrete flange: 6″ deep × 1' 61/2″ wide (3525
psi) concrete; concrete beam: 5″ deep × 8″
wide precast concrete blocks 83/4″ long; “I”
beam reinforcement; 7″ × 4″ × 16 lbs R.S.J.

CRC § 19.1 High relevance — show source text

Structural reinforcing steel shall meet the requirements of ASTM A615, A706M or A996M. The minimum yield strength of reinforcing steel shall be 40,000 psi (Grade 40) (276 MPa). Steel reinforcement for precast concrete foundation walls shall have a minimum concrete cover of [3] / 4 inch (19.1 mm).
Panel-to-panel connections shall be made with Grade II steel fasteners.
The use of nonstructural fibers shall conform to ASTM C1116.
Grout used for bedding precast foundations placed on concrete footings shall meet ASTM C1107.

R402.4 Masonry. Masonry systems shall be designed and installed in accordance with this chapter and shall have a minimum specified compressive strength of 1,500 psi (10.3 MPa).

SECTION R403—FOOTINGS

R403.1 General. All exterior walls shall be supported on continuous solid or fully grouted masonry or concrete footings, crushed stone footings, wood foundations, or other approved structural systems that shall be of sufficient design to accommodate all loads according to Section R301 and to transmit the resulting loads to the soil within the limitations as determined from the character of the soil. Footings shall be supported on undisturbed natural soils or engineered fill. Concrete footing shall be designed and constructed in accordance with the provisions of Section R403 or in accordance with ACI 332.

TABLE R403.1(1)—MINIMUM WIDTH AND THICKNESS FOR CONCRETE FOOTINGS FOR LIGHT-FRAME CONSTRUCTION (inches)a, b, c, d	Col2	Col3	Col4	Col5	Col6	Col7	Col8
GROUND SNOW LOAD OR ROOF LIVE LOAD	STORY AND TYPE OF STRUCTURE WITH LIGHT FRAME	LOAD-BEARING VALUE OF SOIL (psf)	LOAD-BEARING VALUE OF SOIL (psf)	LOAD-BEARING VALUE OF SOIL (psf)	LOAD-BEARING VALUE OF SOIL (psf)	LOAD-BEARING VALUE OF SOIL (psf)	LOAD-BEARING VALUE OF SOIL (psf)
GROUND SNOW LOAD OR ROOF LIVE LOAD	STORY AND TYPE OF STRUCTURE WITH LIGHT FRAME	1,500	2,000	2,500	3,000	3,500	4,000
20 psf roof live load or 25 psf ground snow load	1 story—slab-on-grade	12 × 6	12 × 6	12 × 6	12 × 6	12 × 6	12 × 6
20 psf roof live load or 25 psf ground snow load	1 story—with crawl space	12 × 6	12 × 6	12 × 6	12 × 6	12 × 6	12 × 6
20 psf roof live load or 25 psf ground snow load	1 story—plus basement	16 × 6	12 × 6	12 × 6	12 × 6	12 × 6	12 × 6
20 psf roof live load or 25 psf ground snow load	2 story—slab-on-grade	13 × 6	12 ×

CRC § 5.1 High relevance — show source text
1809 A .3 Stepped footings. The top surface of footings shall be level. The bottom surface of footings shall be permitted to have a slope not exceeding 1 unit vertical in 10 units horizontal (10-percent slope). Footings shall be stepped where it is necessary to change the elevation of the top surface of the footing or where the surface of the ground slopes more than 1 unit vertical in 10 units horizontal (10-percent slope).

Individual steps in continuous footings shall not exceed 18 inches (457 mm) in height and the slope of a series of such steps shall not exceed 1 unit vertical to 2 units horizontal (50 percent slope) unless otherwise recommended by a geotechnical report. The steps shall be detailed on the drawings. The local effects due to the discontinuity of the steps shall be considered in the design of the foundation.

1809 A .4 Depth and width of footings. The minimum depth of footings below the undisturbed ground surface shall be 12 inches (305 mm). Where applicable, the requirements of Section 1809 A .5 shall be satisfied. The minimum width of footings shall be 12 inches (305 mm).

1809 A .5 Frost protection. Except where otherwise protected from frost, foundations and other permanent supports of buildings and structures shall be protected from frost by one or more of the following methods:
1. Extending below the frost line of the locality.
2. Constructing in accordance with ASCE 32.
3. Erecting on solid rock.
Exception: Free-standing buildings meeting all of the following conditions shall not be required to be protected:
1. Assigned to Risk Category I.
2. Area of 600 square feet (56 m [2] ) or less for light-frame construction or 400 square feet (37 m [2] ) or less for other than lightframe construction.
3. Eave height of 10 feet (3048 mm) or less.
Shallow foundations shall not bear on frozen soil unless such frozen condition is of a permanent character.

1809 A .5.1 Frost protection at required exits. Frost protection shall be provided at exterior landings for all required exits with outward-swinging doors. Frost protection shall only be required to the extent necessary to ensure the unobstructed opening of the required exit doors.

1809 A .6 Location of footings. Footings on granular soil shall be so located that the line drawn between the lower edges of adjacent footings shall not have a slope steeper than 30 degrees (0.52 rad) with the horizontal, unless the material supporting the higher footing is braced or retained or otherwise laterally supported in an approved manner or a greater slope has been properly established by engineering analysis.

1809 A .7 Prescriptive footings for light-frame construction. Not permitted by DSA-SS, DSA-SS/CC or OSHPD.

1809 A .8 Plain concrete footings. Not permitted by DSA-SS, DSA-SS/CC or OSHPD.

1809 A .9 Masonry-unit footings. Not permitted by DSA-SS, DSA-SS/CC or OSHPD.

1809 A .10 Pier and curtain wall foundations. Not permitted by DSA-SS, DSA-SS/CC or OSHPD.

Frequently asked questions

When can I use the smallest 12 × 6 footing?

When your wall type and loads match a table entry that permits 12 × 6 (for example, many 1‑story slab‑on‑grade light‑frame walls) and the selected soil bearing capacity is within the table range. Also the absolute minimum per § R403.1.1 is 12 × 6; do not go smaller.

Can I interpolate between soil bearing values in the table?

Yes — the table notes permit linear interpolation between listed soil bearing values. Do not extrapolate beyond the table values.

Do these tables apply if my house is on a steep slope or unusual soil?

Not necessarily. The prescriptive tables assume specific site and loading conditions. For steep slopes, unusual soils, heavy loads, or buildings outside the table assumptions, you must use engineered footing design. The code tables are not a substitute for geotechnical/structural design when conditions differ.

Are there separate rules for brick veneer or CMU walls?

Yes. CRC provides separate prescriptive tables for light‑frame with brick veneer (Table R403.1(2)) and for cast‑in‑place concrete or partially grouted masonry (Table R403.1(3)). Use the table that matches your wall assembly.

What if my project is in a high seismic zone?

Seismic design categories can require continuous solid or fully grouted footings or engineered systems per § R403.1.2 and related seismic provisions; check the Section and design requirements for your seismic zone.

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Related in the CRC

What are the reinforcement and isolated footing requirements?

How deep must footings be and how is frost protection provided?

When are crushed‑stone or precast footings permitted and how are they detailed?

Footings (sizes, depths, reinforcement)

California Residential Code