CRC · California Residential Code

When are soil tests required and how is bearing value handled?

If your building site is likely to have expansive, compressible, shifting or otherwise questionable soils, the building official can require a soil test per **§ R401.4**; if no soils report is provided you may use the CRC’s presumptive bearing values in **§ R401.4.1** (for example, **1,500 psf** for many clays), but if the official suspects bearing less than **1,500 psf** a soils investigation is mandatory.

Ask a question free See coverage

Last reviewed: July 6, 2026

What the code requires — plain English

If local or published data indicate expansive, compressible, shifting or other questionable soils, the building official may require a soil test to determine site conditions. The rule is in § R401.4. Where a full geotechnical evaluation is not provided, the code permits use of presumptive load‑bearing values and soil groups in § R401.4.1 and its tables (Table R401.4.1(1) and Table R401.4.1(2)).

If tests are required, they must be done by an approved agency and the report must give the allowable bearing capacity; if you don't have a report you may use the code's presumptive bearing values. § R401.4 and § R401.4.1 govern this choice.

Requirements in detail

Who decides whether a test is required

  • The building official decides when a soil test is required where quantifiable data indicate expansive soils, compressible soils, shifting soils or other questionable soil characteristics are likely. See § R401.4.
  • If soil testing is performed in areas with Seismic Design Category C or greater, the geotechnical report must include the site class and short‑period spectral response acceleration SDS (per CRC cross‑reference to CBC Section 1613) — see § R401.4.

What the soil test/report must provide (when required)

  • Tests must be done by an approved agency using an approved method and (when required) the geotechnical report must include bearing recommendations and seismic site information as noted above. See § R401.4.
  • If the building official determines that in‑place soils with allowable bearing capacity of less than 1,500 psf are likely, the allowable bearing shall be determined by a soils investigation (see Table R401.4.1(1) notes).

Use of presumptive values instead of a geotechnical report

  • In lieu of a complete geotechnical evaluation, the code allows the presumptive load‑bearing values and soil classifications in § R401.4.1 (Table R401.4.1(1) and Table R401.4.1(2)). These are used to size footings and select foundation details when a soils report is not required/available.

Key numeric thresholds & decision table

Decision factor / value What it means for permit design Code reference
Expansive, compressible, shifting soils likely Building official may require soil test / geotechnical investigation § R401.4
Seismic Design Category C or greater (when soil testing is performed) Geotechnical report must include site class and SDS per CBC §1613 § R401.4
Allowable bearing < 1,500 psf likely Building official must require soils investigation to determine allowable bearing Table R401.4.1(1) note (in § R401.4.1)
Use of presumptive values instead of a report Permitted by § R401.4.1 (Table R401.4.1(1) & (2)) § R401.4.1

Presumptive load‑bearing values (selected from Table R401.4.1(1))

Class of material Presumptive load‑bearing pressure (psf) Code reference
Crystalline bedrock 12,000 psf Table R401.4.1(1) — § R401.4.1
Sedimentary / foliated rock 4,000 psf Table R401.4.1(1) — § R401.4.1
Sandy gravel / gravel (GW, GP) 3,000 psf Table R401.4.1(1) — § R401.4.1
Sands / silty sands / gravels (SW, SP, SM, SC, GM, GC) 2,000 psf Table R401.4.1(1) — § R401.4.1
Clays / silts (CL, ML, MH, CH) 1,500 psf Table R401.4.1(1) — § R401.4.1

(Full tables and soil group properties are in Table R401.4.1(1) and Table R401.4.1(2) in § R401.4.1.)

Exceptions & special cases

  • The building official has discretion: even where presumptive values exist, if local knowledge or tests indicate otherwise, the official can require a geotechnical investigation (see § R401.4 and Table R401.4.1(1) note that soils < 1,500 psf must be investigated).
  • When soils testing is performed in Seismic Design Category C or greater, the geotechnical report must include site class and SDS (CRC cross‑references CBC Section 1613). § R401.4 covers this requirement.
  • For compressible or shifting soils, the code (see § R401.4.2) requires that instead of a full geotechnical evaluation, top/subsoils be removed to a depth/width sufficient to ensure stable moisture content in the active zone and not be reused as fill. (See CRC § R401.4.2.)
  • Local ordinances: many California jurisdictions require preliminary soil reports for subdivisions and may require lot‑by‑lot investigations where expansive soils are indicated (see R401.4.1.1 series). These are local‑ordinance provisions implemented under § R401.4.1.1.

Common mistakes

  • Relying on presumptive values when the building official has indicated a soils investigation is required — if the official expects < 1,500 psf soils, you must obtain a soils report. See Table R401.4.1(1) note and § R401.4.
  • Failing to include site class/SDS in the geotechnical report when testing is done in Seismic Design Category C or greater (site class and SDS are required by § R401.4).
  • Misreading the presumptive table: using extrapolation beyond the table limits. (The CRC and table notes allow linear interpolation between values but disallow extrapolation of footing widths/stone depths in related footing tables.) See table notes in the foundation chapters (e.g., footing table notes).
  • Treating the presumptive values as a “guarantee” of performance: they are conservative defaults for design sizing; unusual site conditions (groundwater, thin weak layers, high expansivity) require a geotechnical report. See § R401.4 and the CBC geotechnical investigation requirements referenced therein.

Worked example — applying the rule with numbers

Scenario: A small 2‑story wood‑frame house will sit on a site where the local planner flags potentially expansive clays. The building official requires a soils investigation.

  • If the soils investigation is required, the geotechnical report must provide the allowable bearing capacity and any foundation recommendations (per § R401.4).
  • If, instead, the building official had not required testing and you used the presumptive value for CL (clay) from Table R401.4.1(1), the allowable bearing would be 1,500 psf. Use that value for preliminary footing sizing.

Numeric footing example (simplified):

  • Suppose a column or wall tributary load is 10,000 lb. Required bearing area = load / allowable bearing = 10,000 lb / 1,500 psf = 6.67 ft².
  • Choose a square footing: side = sqrt(6.67 ft²) ≈ 2.58 ft (31 in). Check minimum footing width and depth requirements (minimum 12 in wide and 6 in thick for concrete footings per § R403.1.1) before final design. If local code or the geotechnical report imposes deeper embedment or larger footings, follow those requirements rather than the presumptive calculation.

Note: This is a simplified calculation to show how the presumptive bearing is used. Final footing sizes should follow the footing tables and/or engineer’s calculations, and must reflect seismic, live/dead loads and local conditions. See related sections for footing tables and minimum sizes.

Related provisions (quick list)

  • § R401.4 — Soil tests (main controlling text)
  • § R401.4.1 — Geotechnical evaluation; Table R401.4.1(1) presumptive load‑bearing values and Table R401.4.1(2) soil classifications
  • § R401.4.1.1 (and subsections) — Local preliminary soil report and lot investigations (ordinance authority)
  • § R401.4.2 — Compressible or shifting soils (removal/stabilization requirement)
  • § R403.1.1 — Minimum footing size; footing width based on load‑bearing values (see tables)
  • Table and footing notes (foundation chapter) — Interpolation allowed within table ranges; do not extrapolate beyond table limits (see footing table notes).

Code references

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

  • CRC § 2.2.1 High relevance — show source text

    This test shall be done by an approved agency using an approved method. Where the seismic design category in accordance with Section R301.2.2.1 is C or greater and where soil testing is performed, the geotechnical report shall include the determination of the site class and the short-period spectral response acceleration, S DS, in accordance with Section 1613 of the California Building Code . The seismic design category shall be assigned in accordance with Table R301.2.2.1.1.

    R401.4.1 Geotechnical evaluation. In lieu of a complete geotechnical evaluation, the load-bearing values in Table R401.4.1(1) and the soil classifications in Table R401.4.1(2) shall be assumed.

    TABLE R401.4.1(1)—PRESUMPTIVE LOAD-BEARING VALUES OF FOUNDATION MATERIALSa Col2
    ** CLASS OF MATERIAL** ** LOAD-BEARING PRESSURE**
    (pounds per square foot)
    Crystalline bedrock 12,000
    Sedimentary and foliated rock 4,000
    Sandy gravel and/or gravel (GW and GP) 3,000
    Sand, silty sand, clayey sand, silty gravel and clayey gravel (SW, SP, SM, SC, GM and GC) 2,000
    Clay, sandy, silty clay, clayey silt, silt and sandy siltclay (CL, ML, MH and CH) 1,500b
    For SI: 1 pound per square foot = 0.0479 kPa.
    a. Where soil tests are required by Section R401.4, the allowable bearing capacities of the soil shall be part of the recommendations.
    b. Where the building official determines that in-place soils with an allowable bearing capacity of less than 1,500 psf are likely to be present at the site, the allowable bearing
    capacity shall be determined by a soils investigation.    		 For SI: 1 pound per square foot = 0.0479 kPa.
    a. Where soil tests are required by Section R401.4, the allowable bearing capacities of the soil shall be part of the recommendations.
    b. Where the building official determines that in-place soils with an allowable bearing capacity of less than 1,500 psf are likely to be present at the site, the allowable bearing
    capacity shall be determined by a soils investigation.

    2025 CALIFORNIA RESIDENTIAL CODE 4-3

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

    FOUNDATIONS

    TABLE R401.4.1(2)—PROPERTIES OF SOILS CLASSIFIED ACCORDING TO THE UNIFIED SOIL CLASSIFICATION SYSTEM Col2 Col3 Col4 Col5 Col6 Col7
    ** SOIL**
    GROUP    		 ** UNIFIED SOIL**
    CLASSIFICATION
    SYSTEM SYMBOL    		 ** SOIL DESCRIPTION** ** USDA**
    TEXTURAL SOIL
    CLASSIFICATION    		 ** DRAINAGE**
    CHARACTERISTICSa    		 ** FROST**
    HEAVE
    POTENTIAL    		 ** VOLUME CHANGE**
    POTENTIAL
    EXPANSIONb
    Group I GW Well-graded gravels, gravel sand
    mixtures,
  • CRC § 0.0479 High relevance — show source text

    Where the building official determines that in-place soils with an allowable bearing capacity of less than 1,500 psf are likely to be present at the site, the allowable bearing
    capacity shall be determined by a soils investigation.|For SI: 1 pound per square foot = 0.0479 kPa.
    a. Where soil tests are required by Section R401.4, the allowable bearing capacities of the soil shall be part of the recommendations.
    b. Where the building official determines that in-place soils with an allowable bearing capacity of less than 1,500 psf are likely to be present at the site, the allowable bearing
    capacity shall be determined by a soils investigation.|

    2025 CALIFORNIA RESIDENTIAL CODE 4-3

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

    FOUNDATIONS

    TABLE R401.4.1(2)—PROPERTIES OF SOILS CLASSIFIED ACCORDING TO THE UNIFIED SOIL CLASSIFICATION SYSTEM Col2 Col3 Col4 Col5 Col6 Col7
    ** SOIL**
    GROUP    		 ** UNIFIED SOIL**
    CLASSIFICATION
    SYSTEM SYMBOL    		 ** SOIL DESCRIPTION** ** USDA**
    TEXTURAL SOIL
    CLASSIFICATION    		 ** DRAINAGE**
    CHARACTERISTICSa    		 ** FROST**
    HEAVE
    POTENTIAL    		 ** VOLUME CHANGE**
    POTENTIAL
    EXPANSIONb
    Group I GW Well-graded gravels, gravel sand
    mixtures, little or no fines    		 N/A Good Low Low
    Group I GP Poorly graded gravels or gravel sand
    mixtures, little or no fines    		 N/A Good Low Low
    Group I SW Well-graded sands, gravelly sands,
    little or no fines    		 N/A Good Low Low
    Group I SP Poorly graded sands or gravelly
    sands, little or no fines    		 Sand Good Low Low
    Group I GM Silty gravels, gravel-sand-silt
    mixtures    		 N/A Good Medium Low
    Group I SM Silty sand, sand-silt mixtures Loamy sand,
    sandy loam    		 Good Medium Low
    Group II GC Clayey gravels, gravel-sand-clay
    mixtures    		 N/A Medium Medium Low
    Group II SC Clayey sands, sand-clay mixture Sandy clay loam,
    sandy clay    		 Medium Medium Low
    Group II ML Inorganic silts and very fine sands,
    rock flour, silty or clayey fine sands
    or clayey silts with slight plasticity    		 Silt, silt loam Medium High Low
    Group II CL Inorganic clays of low to medium
    plasticity, gravelly clays, sandy clays,
    silty clays, lean clays    		 Loam, clay loam,
    silty clay loam    		 Medium Medium Medium to Low
    Group III CH Inorganic clays of high plasticity,
    fat clays    		 Clay, silty clay Poorc Medium High
    Group III MH Inorganic silts,
  • CRC § 1.1.1 High relevance — show source text

    Exception: The provisions of this chapter shall be permitted to be used for wood foundations only in the following situations:

    1. In buildings that have not more than two floors and a roof.
    2. Where interior basement and foundation walls are constructed at intervals not exceeding 50 feet (15 240 mm) .

    Wood foundations in Seismic Design Category D 0, D 1 or D 2 shall be designed in accordance with accepted engineering practice.

    R401.2 Requirements. Foundation construction shall be capable of accommodating all loads in accordance with Section R301 and of transmitting the resulting loads to the supporting soil. Fill soils that support footings and foundations shall be designed, installed and tested in accordance with accepted engineering practice.

    Note: See Section R301.1.1.1 for limited-density owner-built rural dwellings.

    R401.3 Drainage. Surface drainage shall be diverted to a storm sewer conveyance or other approved point of collection that does not create a hazard. Lots shall be graded to drain surface water away from foundation walls. The grade shall fall not fewer than 6 inches (152 mm) within the first 10 feet (3048 mm).

    Exception: Where lot lines, walls, slopes or other physical barriers prohibit 6 inches (152 mm) of fall within 10 feet (3048 mm), drains or swales shall be constructed to ensure drainage away from the structure. Impervious surfaces within 10 feet (3048 mm) of the building foundation shall be sloped not less than 2 percent away from the building.

    R401.4 Soil tests. Where quantifiable data created by accepted soil science methodologies indicate expansive soils, compressible soils, shifting soils or other questionable soil characteristics are likely to be present, the building official shall determine whether to require a soil test to determine the soil’s characteristics at a particular location. This test shall be done by an approved agency using an approved method. Where the seismic design category in accordance with Section R301.2.2.1 is C or greater and where soil testing is performed, the geotechnical report shall include the determination of the site class and the short-period spectral response acceleration, S DS, in accordance with Section 1613 of the California Building Code . The seismic design category shall be assigned in accordance with Table R301.2.2.1.1.

    R401.4.1 Geotechnical evaluation. In lieu of a complete geotechnical evaluation, the load-bearing values in Table R401.4.1(1) and the soil classifications in Table R401.4.1(2) shall be assumed.

    TABLE R401.4.1(1)—PRESUMPTIVE LOAD-BEARING VALUES OF FOUNDATION MATERIALSa Col2
    ** CLASS OF MATERIAL** ** LOAD-BEARING PRESSURE**
    (pounds per square foot)
    Crystalline bedrock 12,000
    Sedimentary and foliated rock 4,000
    Sandy gravel and/or gravel (GW and GP) 3,000
    Sand, silty sand, clayey sand, silty gravel and clayey gravel (SW, SP, SM, SC, GM and GC) 2,000
    Clay, sandy, silty clay, clayey silt, silt and sandy siltclay (CL, ML, MH and CH) 1,500b
    For SI: 1 pound per square foot = 0.0479 kPa.
    a. Where soil tests are required by Section R401.4, the allowable bearing capacities of the soil shall be part of the recommendations.
    b.
  • CRC § 4.1 Medium relevance — show source text

    Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R401.4.1(2).|For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R401.4.1(2).|For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R401.4.1(2).|For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R401.4.1(2).|For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R401.4.1(2).|For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R401.4.1(2).|For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System.

  • California Residential Code Medium relevance — show source text
    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 × 6 12 × 6 12 × 6 12 × 6
    20 psf roof live load or 25 psf
    ground snow load    		 2 story—slab-on-grade 18 × 6 13 × 6 12 × 6 12 × 6 12 × 6 12 × 6
    20 psf roof live load or 25 psf
    ground snow load    		 2 story—with crawl space 20 × 6 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6
    20 psf roof live load or 25 psf
    ground snow load    		 2 story—plus basement 23 × 8 17 × 6 14 × 6 12 × 6 12 × 6 12 × 6
    20 psf roof live load or 25 psf
    ground snow load    		 3 story—slab-on-grade 23 × 8 17 × 6 14 × 6 12 × 6 12 × 6 12 × 6
    20 psf roof live load or 25 psf
    ground snow load    		 3 story—with crawl space 25 × 9 19 × 6 15 × 6 13 × 6 12 × 6 12 × 6
    20 psf roof live load or 25 psf
    ground snow load    		 3 story—plus basement 29 × 11 21 × 7 17 × 6 14 × 6 12 × 6 12 × 6
    30 psf 1 story—slab-on-grade 13 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
    30 psf 1 story—with crawl
  • CRC § 25.4 Medium relevance — show source text

    @ 16″|—|32″
    (287)|25″
    (356)|36″
    (263)|29″
    (345)|21″
    (428)|29″
    (367)|20″
    (484)|—|23″
    (471)|—|—| |2 × 12 @ 12″|—|42″
    (209)|31″
    (263)|—|37″
    (253)|27″
    (317)|36″
    (271)|27″
    (358)|17″
    (447)|31″
    (348)|19″
    (462)|—| |2 × 12 @ 8″|—|48″
    (136)|45″
    (169)|—|48″
    (164)|38″
    (206)|—|40″
    (233)|26″
    (294)|36″
    (230)|29″
    (304)|18″
    (379)| |For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
    a. Tabulated values are for clear-span roof supported solely by exterior bearing walls.
    b. Spans are based on No. 2 Grade lumber of Douglas fir-larch, Southern pine, hem-fir and spruce-pine-fir for repetitive (three or more) members.
    c. Ratio of backspan to cantilever span shall be not less than 3:1.
    d. Connections capable of resisting the indicated uplift force shall be provided at the backspan support.
    e. Uplift force is for a backspan to cantilever span ratio of 3:1. Tabulated uplift values are permitted to be reduced by multiplying by a factor equal to 3 divided by the actual
    backspan ratio provided (3/backspan ratio).
    f. See Section R301.2.2.6, Item 1, for additional limitations on cantilevered floor joists for detached one- and two-family dwellings in Seismic Design Category D0, D1 or D2 and
    townhouses in Seismic Design Category C, D0, D1 or D2.
    g. Linear interpolation shall be permitted for building widths and ground snow loads other than shown.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
    a. Tabulated values are for clear-span roof supported solely by exterior bearing walls.
    b. Spans are based on No. 2 Grade lumber of Douglas fir-larch, Southern pine, hem-fir and spruce-pine-fir for repetitive (three or more) members.
    c. Ratio of backspan to cantilever span shall be not less than 3:1.
    d. Connections capable of resisting the indicated uplift force shall be provided at the backspan support.
    e. Uplift force is for a backspan to cantilever span ratio of 3:1. Tabulated uplift values are permitted to be reduced by multiplying by a factor equal to 3 divided by the actual
    backspan ratio provided (3/backspan ratio).
    f.

  • CRC § 25.4 Medium relevance — show source text

    300 plf|D|30|29|27|21|19|18|16|14|12|12|10|8|9|8|6|7|6|4| |3-story|5,300 plf|W|43|44|44|33|32|33|27|27|26|22|22|22|19|20|19|17|17|17| |For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R401.4.1(2).|For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R401.4.1(2).|For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R401.4.1(2).|For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R401.4.1(2).|For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R401.4.1(2).|For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
    b. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
    c. Soil classes are in accordance with the Unified Soil Classification System.

  • CRC § 4-7 Medium 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

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

    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 ×
  • California Residential Code Medium relevance — show source text

    FOUNDATIONS

    TABLE R403.4—MINIMUM DEPTH (D) AND WIDTH (W) OF CRUSHED STONE FOOTINGSa, b (inches) Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15 Col16 Col17 Col18 Col19 Col20 Col21
    ** NUMBER**
    OF
    STORIES    		 ** UNIFORM**
    WALL LOAD    		 ** DEPTH (D)
    AND WIDTH
    (W)**    		 ** 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)** ** 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)** ** 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)**
    ** NUMBER**
    OF
    STORIES    		 ** UNIFORM**
    WALL LOAD    		 ** DEPTH (D)
    AND WIDTH
    (W)**    		 ** 1,500** ** 1,500** ** 1,500** ** 2,000** ** 2,000** ** 2,000** ** 2,500** ** 2,500** ** 2,500** ** 3,000** ** 3,000** ** 3,000** ** 3,500** ** 3,500** ** 3,500** ** 4,000** ** 4,000** ** 4,000**
    ** NUMBER**
    OF
    STORIES    		 ** UNIFORM**
    WALL LOAD    		 ** DEPTH (D)
    AND WIDTH
    (W)**    		 ** MH, CH,**
    CL, MLc    		 ** MH, CH,**
    CL, MLc    		 ** MH, CH,**
    CL, MLc    		 ** SC, GC, SM,**
    GM, SP, SWc    		 ** SC, GC, SM,**
    GM, SP, SWc    		 ** SC, GC, SM,**
    GM, SP, SWc    		 ** GP, GWc** ** GP, GWc** ** GP,
  • CRC § 25.4 Medium relevance — show source text

    6|12 × 6| |50 psf|1 story—plus basement|20 × 60|15 × 6|12 × 6|12 × 6|12 × 6|12 × 6| |50 psf|2 story—slab-on-grade|20 × 6|15 × 6|12 × 6|12 × 6|12 × 6|12 × 6| |50 psf|2 story—with crawl space|22 × 7|17 × 6|13 × 6|12 × 6|12 × 6|12 × 6| |50 psf|2 story—plus basement|25 × 9|19 × 6|15 × 6|13 × 6|12 × 6|12 × 6| |50 psf|3 story—slab-on-grade|25 × 9|19 × 6|15 × 6|13 × 6|12 × 6|12 × 6| |50 psf|3 story—with crawl space|27 × 10|21 × 7|16 × 6|14 × 6|12 × 6|12 × 6| |50 psf|3 story—plus basement|31 × 12|23 × 8|18 × 6|15 × 6|13 × 6|12 × 6| |70 psf|1 story—slab-on-grade|14 × 6|12 × 6|12 × 6|12 × 6|12 × 6|12 × 6| |70 psf|1 story—with crawl space|17 × 6|14 × 6|12 × 6|12 × 6|12 × 6|12 × 6| |70 psf|1 story—plus basement|22 × 7|16 × 6|13 × 6|12 × 6|12 × 6|12 × 6| |70 psf|2 story—slab-on grade|21 × 7|16 × 6|13 × 6|12 × 6|12 × 6|12 × 6| |70 psf|2 story—with crawl space|24 × 8|18 × 6|14 × 6|12 × 6|12 × 6|12 × 6| |70 psf|2 story—plus basement|27 × 10|20 × 6|16 × 6|13 × 6|12 × 6|12 × 6| |70 psf|3 story—slab-on-grade|27 × 10|20 × 6|16 × 6|13 × 6|12 × 6|12 × 6| |70 psf|3 story—with crawl space|29 × 11|22 × 7|17 × 6|15 × 6|12 × 6|12 × 6| |70 psf|3 story—plus basement|32 × 12|24 × 8|19 × 6|16 × 6|14 × 6|12 × 6| |For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 47.9 N/m2.
    a. Linear interpolation of footing width is permitted between the soil bearing pressures in the table. Extrapolation is not permitted.
    b.

  • CRC § 3.2 Medium relevance — show source text

    Exception: Where the frost-protected shallow foundation abuts the heated structure to form an inside corner, vertical insulation extending along the adjoining foundation is not required.

    R403.3.2 Protection of horizontal insulation below ground. Horizontal insulation placed less than 12 inches (305 mm) below the ground surface or that portion of horizontal insulation extending outward more than 24 inches (610 mm) from the foundation edge shall be protected against damage by use of a concrete slab or asphalt paving on the ground surface directly above the insulation or by cementitious board, plywood rated for below-ground use, or other approved materials placed below ground, directly above the top surface of the insulation.

    R403.3.3 Drainage. Final grade shall be sloped in accordance with Section R401.3. In other than Group I Soils, as detailed in Table R401.4.1(2), gravel or crushed stone beneath horizontal insulation below ground shall drain to daylight or into an approved sewer system.

    R403.3.4 Termite protection. The use of foam plastic in areas of “very heavy” termite infestation probability shall be in accordance with Section R305.4.

    R403.4 Footings for precast concrete foundations. Footings for precast concrete foundations shall comply with Section R403.4.

    4-20 2025 CALIFORNIA RESIDENTIAL CODE

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

    FOUNDATIONS

    FIGURE R403.4(1)—BASEMENT OR CRAWL SPACE WITH PRECAST FOUNDATION WALL BEARING ON CRUSHED STONE

    2025 CALIFORNIA RESIDENTIAL CODE 4-21

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

    FOUNDATIONS

    TABLE R403.4—MINIMUM DEPTH (D) AND WIDTH (W) OF CRUSHED STONE FOOTINGSa, b (inches) Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15 Col16 Col17 Col18 Col19 Col20 Col21
    ** NUMBER**
    OF
    STORIES    		 ** UNIFORM**
    WALL LOAD    		 ** DEPTH (D)
    AND WIDTH
    (W)**    		 ** 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)** ** 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)** ** LOAD-BEARING VALUE OF SOIL (psf)** ** LOAD-BEARING VALUE OF SOIL (psf)** ** LOAD-BEARING VALUE OF SOIL
  • CRC § 4-8 Medium relevance — show source text

    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|

    4-8 2025 CALIFORNIA RESIDENTIAL CODE

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

    FOUNDATIONS

    TABLE R403.1(3)—MINIMUM WIDTH AND THICKNESS FOR CONCRETE FOOTINGS WITH
    CAST-IN-PLACE CONCRETE OR PARTIALLY GROUTED MASONRY WALL 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 CMU OR
    CONCRETE    		 ** 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 CMU OR
    CONCRETE    		 ** 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 13 × 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 16 × 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 19 × 6 14 × 6 12 × 6 12 × 6 12 × 6 12 ×

Frequently asked questions

When exactly does the building official require a soils investigation?

The code says the building official shall determine whether a soil test is required where quantifiable data indicate expansive, compressible, shifting or other questionable soil characteristics are likely. That determination is made under § R401.4.

Can I just use the prescriptive bearing values in the code and skip testing?

Yes, if the building official allows use of the presumptive values in § R401.4.1. However, if the official determines soils with allowable bearing < 1,500 psf are likely, a soils investigation is required and presumptive values cannot be used in place of a report.

What must a geotechnical report include in higher seismic areas?

If soil testing is performed in Seismic Design Category C or greater, the geotechnical report must include site class and SDS in accordance with CBC cross‑references, as required by § R401.4.

Are there code limits on using the footing tables tied to bearing values?

Yes — the footing tables allow linear interpolation between table values but do not permit extrapolation beyond table limits. See the footing table notes in the foundation chapter (related tables).

If soils are compressible or shifting, can I just stabilize the soil?

For compressible or shifting soils the code requires removal to a stable depth and width so those soils are not used as fill within the active zone, unless properly treated; see § R401.4.2.

More in California Residential Code

Ask about the CRC

Get cited, plain-English answers on the California Residential Code for your project — any code section, any scenario.

Start Free Trial

Related in the CRC

What foundations and foundation spaces does the CRC chapter cover?

How must the site be graded and surface drainage directed away from foundations?

What are the basic design duties for foundations and soil/fill?

General foundation requirements

California Residential Code