General foundation requirements

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

• CRC § 4.1.1 High relevance — show source text

  2||||X|||||||||||||||||||| |R401.4.1.1 through
  R401.4.1.1.5||||X|||||||||||||||||||| |R404.5.1||||X|||||||||||||||||||| |R408.3||||X|||||||||||||||||||| |R408.4||||X|||||||||||||||||||| |R408.8||||||||||||||||||||X||||

  The state agency does not adopt sections identified with the following symbol: †

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  4 FOUNDATIONS

  User notes:

  About this chapter: Chapter 4 provides requirements for constructing footings and walls for foundations of wood, masonry, concrete and precast concrete. In addition to a foundation’s ability to support the required design loads, this chapter addresses several other factors that can affect foundation performance. These include controlling surface water and subsurface drainage, requiring soil tests where conditions warrant and evaluating proximity to slopes and minimum depth requirements. This chapter also provides requirements to minimize adverse effects of moisture, decay and pests in basements and crawl spaces.

  SECTION R401—GENERAL

  R401.1 Application. The provisions of this chapter shall control the design and construction of the foundation and foundation spaces for buildings. In addition to the provisions of this chapter, the design and construction of foundations in flood hazard areas as established by Table R301.2 shall meet the provisions of Section R306. Wood foundations shall be designed and installed in accordance with AWC PWF.

  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.

• CRC § 1.6.1 High relevance — show source text

  R403.1.6.1 Foundation anchorage in Seismic Design Categories C, D 0 , D 1 and D 2 . In addition to the requirements of Section R403.1.6, the following requirements shall apply to wood light-frame structures in Seismic Design Categories D 0, D 1 and D 2 and wood light-frame townhouses in Seismic Design Category C.

  1. Plate washers conforming to Section R602.11.1 shall be provided for all anchor bolts over the full length of required braced wall lines except where approved anchor straps are used. Properly sized cut washers shall be permitted for anchor bolts in wall lines not containing braced wall panels.
  2. Interior braced wall plates shall have anchor bolts spaced at not more than 6 feet (1829 mm) on center and located within 12 inches (305 mm) of the ends of each plate section where supported on a continuous foundation.
  3. Interior bearing wall sole plates shall have anchor bolts spaced at not more than 6 feet (1829 mm) on center and located within 12 inches (305 mm) of the ends of each plate section where supported on a continuous foundation.
  4. The maximum anchor bolt spacing shall be 4 feet (1219 mm) for buildings over two stories in height.
  5. Stepped cripple walls shall conform to Section R602.11.2.
  6. Where continuous wood foundations in accordance with Section R404.2 are used, the force transfer shall have a capacity equal to or greater than the connections required by Section R602.11.1 or the braced wall panel shall be connected to the wood foundations in accordance with the braced wall panel-to-floor fastening requirements of Table R602.3(1).

  R403.1.7 Footings on or adjacent to slopes. The placement of buildings and structures on or adjacent to slopes steeper than 1 unit vertical in 3 units horizontal (33.3-percent slope) shall conform to Sections R403.1.7.1 through R403.1.7.4.

  R403.1.7.1 Building clearances from ascending slopes. In general, buildings below slopes shall be set a sufficient distance from the slope to provide protection from slope drainage, erosion and shallow failures. Except as provided in Section R403.1.7.4 and Figure R403.1.7.1, the following criteria will be assumed to provide this protection. Where the existing slope is steeper than 1 unit vertical in 1 unit horizontal (100-percent slope), the toe of the slope shall be assumed to be at the intersection of a horizontal plane drawn from the top of the foundation and a plane drawn tangent to the slope at an angle of 45 degrees (0.79 rad) to the horizontal. Where a retaining wall is constructed at the toe of the slope, the height of the slope shall be measured from the top of the wall to the top of the slope.

  2025 CALIFORNIA RESIDENTIAL CODE 4-15

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  FOUNDATIONS

  For SI: 1 foot = 304.8 mm.

  FIGURE R403.1.7.1—FOUNDATION CLEARANCE FROM SLOPES

  FACE OF

  AT LEAST THE SMALLER OF H/2 AND 15 FEET

• CRC § 3-82 High relevance — show source text

  R336 Large Family Day-Care Homes . . . . . . . . . . . . . . . . . . . 3-82

  R337 Materials and Construction Methods for Exterior

  Wildfire Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-83

  R338 Electric Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-83

  2025 CALIFORNIA RESIDENTIAL CODE xxi

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  CONTENTS

  R339 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-84

  R340 Pollutant Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-84

  CHAPTER 4 FOUNDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

  R401 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

  R402 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

  R403 Footings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

  R404 Foundation and Retaining Walls . . . . . . . . . . . . . . . . 4-24

  R405 Foundation Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . 4-42

  R406 Foundation Waterproofing and Dampproofing . . . 4-43

  R407 Columns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-44

  R408 Under-Floor Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-44

  CHAPTER 5 FLOORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

  R501 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

  R502 Wood Floor Framing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

  R503 Floor Sheathing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12

  R504 Pressure Preservative-Treated Wood

• CRC § 1.7 High relevance — show source text

  R403.1.7 Footings on or adjacent to slopes. The placement of buildings and structures on or adjacent to slopes steeper than 1 unit vertical in 3 units horizontal (33.3-percent slope) shall conform to Sections R403.1.7.1 through R403.1.7.4.

  R403.1.7.1 Building clearances from ascending slopes. In general, buildings below slopes shall be set a sufficient distance from the slope to provide protection from slope drainage, erosion and shallow failures. Except as provided in Section R403.1.7.4 and Figure R403.1.7.1, the following criteria will be assumed to provide this protection. Where the existing slope is steeper than 1 unit vertical in 1 unit horizontal (100-percent slope), the toe of the slope shall be assumed to be at the intersection of a horizontal plane drawn from the top of the foundation and a plane drawn tangent to the slope at an angle of 45 degrees (0.79 rad) to the horizontal. Where a retaining wall is constructed at the toe of the slope, the height of the slope shall be measured from the top of the wall to the top of the slope.

  2025 CALIFORNIA RESIDENTIAL CODE 4-15

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  FOUNDATIONS

  For SI: 1 foot = 304.8 mm.

  FIGURE R403.1.7.1—FOUNDATION CLEARANCE FROM SLOPES

  FACE OF

  AT LEAST THE SMALLER OF H/2 AND 15 FEET

  R403.1.7.2 Footing setback from descending slope surfaces. Footings on or adjacent to slope surfaces shall be founded in material with an embedment and setback from the slope surface sufficient to provide vertical and lateral support for the footing without detrimental settlement. Except as provided for in Section R403.1.7.4 and Figure R403.1.7.1, the following setback is deemed adequate to meet the criteria. Where the slope is steeper than 1 unit vertical in 1 unit horizontal (100-percent slope), the required setback shall be measured from an imaginary plane 45 degrees (0.79 rad) to the horizontal, projected upward from the toe of the slope.

  R403.1.7.3 Foundation elevation. On graded sites, the top of any exterior foundation shall extend above the elevation of the street gutter at point of discharge or the inlet of an approved drainage device not less than 12 inches (305 mm) plus 2 percent. Alternate elevations are permitted subject to the approval of the building official, provided that it can be demonstrated that required drainage to the point of discharge and away from the structure is provided at all locations on the site.

  R403.1.7.4 Alternate setbacks and clearances. Alternate setbacks and clearances are permitted, subject to the approval of the building official. The building official is permitted to require an investigation and recommendation of a qualified engineer to demonstrate that the intent of this section has been satisfied. Such an investigation shall include consideration of material, height of slope, slope gradient, load intensity and erosion characteristics of slope material.

  R403.1.8 Foundations on expansive soils. Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1808.6 of the California Building Code .

  Exception: Slab-on-ground and other foundation systems that have performed adequately in soil conditions similar to those encountered at the building site are permitted subject to the approval of the building official.

• CRC § 4-39 High relevance — show source text

  7. In Seismic Design Categories D 0, D 1 and D 2, prescriptive reinforcement shall be provided in the horizontal and vertical direction. Provide minimum horizontal joint reinforcement of two No. 9 gage wires spaced not less than 6 inches (152

  2025 CALIFORNIA RESIDENTIAL CODE 4-39

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  FOUNDATIONS

  mm) or one [1] / 4 -inch-diameter (6.4 mm) wire at 10 inches (254 mm) on center vertically. Provide minimum vertical reinforcement of one No. 4 bar at 48 inches (1220 mm) on center horizontally grouted in place.

  FIGURE R404.1.5.3—FOUNDATION WALL CLAY MASONRY CURTAIN WALL WITH CONCRETE MASONRY PIERS

  For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 degree = 0.0175 rad.

  R404.1.6 Height above finished grade. Concrete and masonry foundation walls shall extend above the finished grade adjacent to the foundation at all points not less than 4 inches (102 mm) where masonry veneer is used and not less than 6 inches (152 mm) elsewhere.

  R404.1.7 Backfill placement. Backfill shall not be placed against the wall until the wall has sufficient strength and has been anchored to the floor above, or has been sufficiently braced to prevent damage by the backfill.

  Exception: Bracing is not required for walls supporting less than 4 feet (1219 mm) of unbalanced backfill.

  R404.1.8 Rubble stone masonry. Rubble stone masonry foundation walls shall have a minimum thickness of 16 inches (406 mm), shall not support an unbalanced backfill exceeding 8 feet (2438 mm) in height, shall not support a soil pressure greater than 30 pounds per square foot per foot (4.71 kPa/m), and shall not be constructed in Seismic Design Categories D 0, D 1, D 2 or townhouses in Seismic Design Category C, as established in Figure R301.2(2).

  R404.1.9 Isolated masonry piers. Isolated masonry piers shall be constructed in accordance with this section and the general masonry construction requirements of Section R606. Hollow masonry piers shall have a minimum nominal thickness of 8 inches (203 mm), with a nominal height not exceeding four times the nominal thickness and a nominal length not exceeding three times the nominal thickness. Where hollow masonry units are solidly filled with concrete or grout, piers shall be permitted to have a nominal height not exceeding ten times the nominal thickness. Footings for isolated masonry piers shall be sized in accordance with Section R403.1.1.

  R404.1.9.1 Pier cap. Hollow masonry piers shall be capped with 4 inches (102 mm) of solid masonry or concrete, a masonry cap block, or shall have cavities of the top course filled with concrete or grout. Where required, termite protection for the pier cap shall be provided in accordance with Section R305.

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  FOUNDATIONS

  **R404.1.9.2 Masonry piers supporting floor girders.

• CRC § 1.7.3 High relevance — show source text

  R403.1.7.3 Foundation elevation. On graded sites, the top of any exterior foundation shall extend above the elevation of the street gutter at point of discharge or the inlet of an approved drainage device not less than 12 inches (305 mm) plus 2 percent. Alternate elevations are permitted subject to the approval of the building official, provided that it can be demonstrated that required drainage to the point of discharge and away from the structure is provided at all locations on the site.

  R403.1.7.4 Alternate setbacks and clearances. Alternate setbacks and clearances are permitted, subject to the approval of the building official. The building official is permitted to require an investigation and recommendation of a qualified engineer to demonstrate that the intent of this section has been satisfied. Such an investigation shall include consideration of material, height of slope, slope gradient, load intensity and erosion characteristics of slope material.

  R403.1.8 Foundations on expansive soils. Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1808.6 of the California Building Code .

  Exception: Slab-on-ground and other foundation systems that have performed adequately in soil conditions similar to those encountered at the building site are permitted subject to the approval of the building official.

  R403.1.8.1 Expansive soils classifications. Soils meeting all of the following provisions shall be considered to be expansive, except that tests to show compliance with Items 1, 2 and 3 shall not be required if the test prescribed in Item 4 is conducted:

  1. Plasticity Index (PI) of 15 or greater, determined in accordance with ASTM D4318.

  2. More than 10 percent of the soil particles pass a No. 200 sieve (75 μ m), determined in accordance with ASTM D422.

  3. More than 10 percent of the soil particles are less than 5 micrometers in size, determined in accordance with ASTM D422.

  4. Expansion Index greater than 20, determined in accordance with ASTM D4829.

  R403.2 Footings for wood foundations. Footings for wood foundations shall be in accordance with Figures R403.1(2) and R403.1(3). Gravel shall be washed and well graded. The maximum size stone shall not exceed [3] / 4 inch (19.1 mm). Gravel shall be free from organic, clayey or silty soils. Sand shall be coarse, not smaller than [1] / 16 -inch (1.6 mm) grains and shall be free from organic, clayey or silty soils. Crushed stone shall have a maximum size of [1] / 2 inch (12.7 mm).

  R403.3 Frost-protected shallow foundations. For buildings where the monthly mean temperature of the building is maintained at not less than 64°F (18°C), footings are not required to extend below the frost line where protected from frost by insulation in accordance with Figure R403.3(1) and Table R403.3(1). Foundations protected from frost in accordance with Figure R403.3(1) and Table R403.3(1) shall not be used for unheated spaces such as porches, utility rooms, garages and carports, and shall not be attached to basements or crawl spaces that are not maintained at a minimum monthly mean temperature of 64°F (18°C).

  Materials used below grade for the purpose of insulating footings against frost shall be labeled as complying with ASTM C578.

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• CRC § 2.4 Medium relevance — show source text

  Framing members that are both load-bearing and stabilization members shall meet the requirements of Section R602 and this section. Nonstructural stabilization members shall be not more than 32 inches (813 mm) on center. 2. Horizontal stabilization shall be installed at not more than 24 inches (610 mm) on center and in accordance with Figure BI103.2.4(1), BI103.2.4(2) or BI103.2.4(3). Horizontal stabilization shall be of any of the following with the stated minimum dimensions: [3] / 4 -inch (19.1 mm) bamboo, [1] / 2 -inch (12.7 mm) fiberglass rod, 1-inch (25 mm) wood dowel or nominal 1-inch by 2-inch (25 mm by 51 mm) wood.

  FIGURE BI103.2.4(1)—LIGHT STRAW-CLAY WALL WITH LARSEN TRUSSES

  DOUBLE TOP PLATE

  VERTICAL SOLID BLOCKING

  FLAT SOLID BLOCKING

  LADDER (LARSEN) TRUSSES MADE WITH 2x4s AND GUSSETS PER SECTION BI103.2.4, ITEM 1

  GUSSETS: [3] / 8 ″ x 3 ″ PLYWOOD OR 1x4 FASTENERS: 4–4d NAILS OR 4–1¾ ″ STAPLES

  WOOD OR METAL STRAP BRACING (LIB) PER TABLE 602.10.4 WHERE APPLICABLE PER SECTION R602.10

  LIGHT STRAW-CLAY INFILL

  HORIZONTAL STABILIZATION OF LIGHT STRAW-CLAY PER SECTION BI103.4, ITEM 2

  ANCHORAGE PER SECTION R403.1.6

  2X SILL PLATE

  CONCRETE OR MASONRY FOUNDATION PER SECTION R401

  FRAMING FASTENERS PER TABLE R602.3(1)

  For SI: 1 inch = 25.4 mm.

  APPENDIX BI-4 2025 CALIFORNIA RESIDENTIAL CODE

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  APPENDIX BI — LIGHT STRAW-CLAY CONSTRUCTION

  FIGURE BI103.2.4(2)—LIGHT STRAW-CLAY WALL, SINGLE STUD WIDTH

  DOUBLE TOP PLATE

  FLAT SOLID BLOCKING

  WOOD METAL STRAP BRACING (LIB) PER TABLE R602.10.4 WHERE APPLICABLE PER SECTION R602.10

  2X STUDS PER SECTION BI103.2.4, ITEM 1

  1x1 CLEAT CENTERED ON EACH STUD FACE BETWEEN HORIZONTAL STABILIZATION

  HORIZONTAL STABILIZATION OF LIGHT STRAW-CLAY PER SECTION BI103.2.4, ITEM 2

  LIGHT STRAY-CLAY INFILL

  ANCHORAGE PER SECTION R403.1.6

  2X SILL PLATE

  CONCRETE OR MASONRY FOUNDATION PER SECTION R401

  FRAMING FASTENERS PER TABLE R602.3(1)

  FIGURE BI103.2.4(3)—LIGHT STRAW-CLAY WALL WITH BLIND STUDS

  DOUBLE TOP PLATES

  2X LET-IN PLATE

  WOOD METAL BRACING (LIB) PER TABLE R602.10.4 WHERE APPLICABLE PER SECTION R602.10

  2x6 MINIMUM STUDS PER SECTION BI103.2.4, ITEM 1

  LIGHT STRAW-CLAY INFILL

• CRC § 5.1 Medium 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.

• CRC § 2.1 Medium relevance — show source text

  See Section R402.2 for maximum cementitious materials content.
  f. For garage floors with a steel-troweled finish, reduction of the total air content (percent by volume of concrete) to not less than 3 percent is permitted if the specified
  compressive strength of the concrete is increased to not less than 4,000 psi.|

  R402.2.1 Materials for concrete. Materials for concrete shall comply with the requirements of Section R608.5.1.

  R402.3 Precast concrete. Precast concrete foundations shall be designed in accordance with Section R404.5 and shall be installed in accordance with the provisions of this code and the manufacturer’s instructions.

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  FOUNDATIONS

  R402.3.1 Precast concrete foundation materials. Materials used to produce precast concrete foundations shall meet the following requirements:

  1. All concrete used in the manufacture of precast concrete foundations shall have a minimum compressive strength of 5,000 psi (34 470 kPa) at 28 days. Concrete exposed to a freezing and thawing environment shall be air entrained with a minimum total air content of 5 percent.

  2. 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).

  3. Panel-to-panel connections shall be made with Grade II steel fasteners.

  4. The use of nonstructural fibers shall conform to ASTM C1116.

  5. 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,

• CRC § 19.1 Medium relevance — show source text

  2. 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).

  3. Panel-to-panel connections shall be made with Grade II steel fasteners.

  4. The use of nonstructural fibers shall conform to ASTM C1116.

  5. 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 § 6.9 Medium relevance — show source text

  BJ105.6.9 Separation of exterior plaster and foundation. Exterior plaster shall be separated from the building foundation with a moisture barrier.

  BJ105.7 Inspections. The building official shall inspect the following aspects of strawbale construction in accordance with Section R109.1:

  1. Sill plate anchors, as part of and in accordance with Section R109.1.1.
  2. Mesh placement and attachment, where mesh is required by this appendix.
  3. Pins, where required by and in accordance with Section BJ105.4.

  BJ105.8 Voids and stuffing. Voids between bales and between bales and framing members shall not exceed 4 inches (102 mm) in width, and such voids shall be tightly stuffed with flakes, loose straw or straw-clay before application of finish.

  SECTION BJ106—STRAWBALE WALLS—STRUCTURAL

  BJ106.1 General. Plastered strawbale walls shall be permitted to be used as structural walls in accordance with the prescriptive provisions of this section.

  BJ106.2 Building limitations and requirements for use of strawbale structural walls. Buildings using strawbale structural walls shall be subject to the following limitations and requirements:

  1. Number of stories: Not more than one, except that two stories shall be allowed with an approved engineered design.
  2. Building height: Not more than 25 feet (7620 mm), except that greater heights shall be allowed with an approved engineered design.
  3. Wall height: In accordance with Table BJ105.4, BJ106.13(2) or BJ106.13(3), as applicable, whichever is most restrictive.
  4. Braced wall panel lengths: The greater of the values determined in accordance with Tables BJ106.13(2) and BJ106.13(3) for buildings using strawbale braced wall panels, or in accordance with Item 4 of Section BJ105.2 for buildings with load-bearing strawbale walls that do not use strawbale braced wall panels.

  BJ106.3 Loads and other limitations. Live and dead loads and other limitations shall be in accordance with Section R301. Strawbale wall dead loads shall not exceed 60 psf (2872 N/m [2] ) per face area of wall.

  BJ106.4 Foundations. Foundations for plastered strawbale walls shall be in accordance with Chapter 4, Figure BJ105.1(1), Figure BJ105.1(2) or an approved engineered design.

  2025 CALIFORNIA RESIDENTIAL CODE APPENDIX BJ-11

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

  APPENDIX BJ — STRAWBALE CONSTRUCTION

  BJ106.5 Orientation and configuration of bales. Bales in strawbale structural walls shall be laid flat or on-edge and in a running bond or stack bond, except that bales in structural walls with unreinforced plasters shall be laid in a running bond only.

  BJ106.6 Plaster on structural walls. Plaster on load-bearing walls shall be in accordance with Table BJ106.12. Plaster on shear walls shall be in accordance with Table BJ106.13(1).

• CRC § 2.4 Medium relevance — show source text

  HORIZONTAL STABILIZATION PER SECTION BI103.2.4, ITEM 2

  2X BOTTOM PLATE

  2X SILL PLATE

  ANCHORAGE PER SECTION R403.1.6

  CONCRETE OR MASONRY FOUNDATION PER SECTION R401

  FRAMING FASTENERS PER TABLE R602.3(1)

  2025 CALIFORNIA RESIDENTIAL CODE APPENDIX BI-5

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

  APPENDIX BI — LIGHT STRAW-CLAY CONSTRUCTION

  BI103.3 Materials. The materials used in light straw-clay construction shall be in accordance with Sections BI103.3.1 through BI103.3.3.

  BI103.3.1 Straw requirements. Straw shall be stems of wheat, rye, oats, rice or barley, and shall be free of visible decay, insects and green plant material.

  BI103.3.2 Clay subsoil requirements. Suitability of clay subsoil shall be determined in accordance with Table BI103.2.3.

  BI103.3.3 Light straw-clay mixture. A light straw-clay mixture shall consist of loose straw mixed and coated with clay slip such that there is not more than 5 percent uncoated straw, and shall be in accordance with Table BI103.2.3.

  BI103.4 Wall construction. Light straw-clay wall construction shall be in accordance with the requirements of Sections BI103.4.1 through BI103.4.7.

  BI103.4.1 Light straw-clay maximum thickness. The maximum thickness of light straw-clay shall be in accordance with Table BI103.2.3.

  BI103.4.2 Distance above grade. Light straw-clay and its exterior finish shall be not less than 8 inches (203 mm) above exterior finished grade.

  BI103.4.3 Moisture barrier. An approved moisture barrier shall separate the bottom of light straw-clay walls from any masonry or concrete foundation or slab that directly supports the walls. Penetrations and joints in the barrier shall be sealed with an approved sealant.

  BI103.4.4 Contact with wood members. Light straw-clay shall be permitted to be in contact with untreated wood members.

  BI103.4.5 Contact with nonwood structural members. Nonwood structural members in contact with light straw-clay shall be resistant to corrosion or shall be coated to prevent corrosion with an approved coating.

  BI103.4.6 Installation. Light straw-clay shall be installed in accordance with the following:

  1. Formwork shall be sufficiently strong to resist bowing where the light straw-clay is compacted into the forms.

  2. Light straw-clay shall be uniformly placed into forms and evenly tamped to achieve stable walls free of voids. Light straw-clay shall be placed in lifts of not more than 6 inches (152 mm) and shall be thoroughly tamped before additional material is added.

  3. Temporary formwork shall be removed from walls within 24 hours after tamping, and walls shall remain exposed until moisture content is in accordance with Section BI103.5.1. Visible voids shall be filled with light straw-clay or other insulative material prior to plastering.