ADOPTS WITH AMENDMENTS:

International Residential Code 2018 (IRC 2018)

Part IV Energy Conservation

Part V Mechanical

Part VI Fuel Gas

Part VII Plumbing

Part VIII Electrical

Heads up: There are no amended sections in this chapter.

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(1) shall meet the provisions of Section R322. 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 D0, D1 or D2 shall be designed in accordance with accepted engineering practice.

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.

Surface drainage shall be diverted to a storm sewer conveyance or other approved point of collection that does not create a hazard to the dwelling unit. Lots shall be graded to drain surface water away from foundation walls. The grade shall fall a minimum of 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 a minimum of 1.0 percent away from the building.

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.

In lieu of a complete geotechnical evaluation, the load-bearing values in Table R401.4.1 shall be assumed.

TABLE R401.4.1

PRESUMPTIVE LOAD-BEARING VALUES OF FOUNDATION MATERIALSa

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.

  1. Where soil tests are required by Section R401.4, the allowable bearing capacities of the soil shall be part of the recommendations.
  2. 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.
Instead of a complete geotechnical evaluation, where top or subsoils are compressible or shifting, they shall be removed to a depth and width sufficient to ensure stable moisture content in each active zone and shall not be used as fill or stabilized within each active zone by chemical, dewatering or presaturation.
Wood foundation systems shall be designed and installed in accordance with the provisions of this code.
Fasteners used below grade to attach plywood to the exterior side of exterior basement or crawlspace wall studs, or fasteners used in knee wall construction, shall be of Type 304 or 316 stainless steel. Fasteners used above grade to attach plywood and all lumber-to-lumber fasteners except those used in knee wall construction shall be of Type 304 or 316 stainless steel, silicon bronze, copper, hot-dipped galvanized (zinc coated) steel nails, or hot-tumbled galvanized (zinc coated) steel nails. Electro-galvanized steel nails and galvanized (zinc coated) steel staples shall not be permitted.
Lumber and plywood shall be pressure-preservative treated and dried after treatment in accordance with AWPA U1 (Commodity Specification A, Special Requirement 4.2), and shall bear the label of an accredited agency. Where lumber or plywood is cut or drilled after treatment, the treated surface shall be field treated with copper naphthenate, the concentration of which shall contain not less than 2-percent copper metal, by repeated brushing, dipping or soaking until the wood cannot absorb more preservative.

R402.2 Concrete

ILLUSTRATION

Concrete shall have a minimum specified compressive strength of f'c, as shown in Table R402.2. Concrete subject to moderate or severe weathering as indicated in Table R301.2(1) shall be air entrained as specified in Table R402.2. The maximum weight of fly ash, other pozzolans, silica fume, slag or blended cements that is included in concrete mixtures for garage floor slabs and for exterior porches, carport slabs and steps that will be exposed to deicing chemicals shall not exceed the percentages of the total weight of cementitious materials specified in Section 19.3.3.4 of ACI 318. Materials used to produce concrete and testing thereof shall comply with the applicable standards listed in Chapters 19 and 20 of ACI 318 or ACI 332.

TABLE R402.2

MINIMUM SPECIFIED COMPRESSIVE STRENGTH OF CONCRETE

TYPE OR LOCATION OF CONCRETE CONSTRUCTION MINIMUM SPECIFIED COMPRESSIVE STRENGTHa (f'c)
Weathering Potentialb
Negligible Moderate Severe
Basement walls, foundations and other concrete not exposed to the weather 2,500 2,500 2,500c
Basement slabs and interior slabs on grade, except garage floor slabs 2,500 2,500 2,500c
Basement walls, foundation walls, exterior walls and other vertical concrete work exposed to the weather 2,500 3,000d 3,000d
Porches, carport slabs and steps exposed to the weather, and garage floor slabs 2,500 3,000d, e, f 3,500d, e, f

For SI: 1 pound per square inch = 6.895 kPa.

  1. Strength at 28 days psi.
  2. See Table R301.2(1) for weathering potential.
  3. Concrete in these locations that is subject to freezing and thawing during construction shall be air-entrained concrete in accordance with Footnote d.
  4. Concrete shall be air-entrained. Total air content (percent by volume of concrete) shall be not less than 5 percent or more than 7 percent.
  5. See Section R402.2 for maximum cementitious materials content.
  6. 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.
Materials for concrete shall comply with the requirements of Section R608.5.1.
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.

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, A706 or A996. 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.
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

ILLUSTRATION

R403.1 General

ILLUSTRATION

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.

Exceptions:

  1. One-story detached accessory structures used as tool and storage sheds, playhouses and similar uses, not exceeding 256 square feet (24 m2) of building area, provided that all of the following conditions are met:

    1.1.  The building eave height is 10 feet (3 m) or less.

    1.2.  The maximum height from the finished floor level to grade does not exceed 18 inches (457 mm).

    1.3.  The supporting structural elements in direct contact with the ground shall be placed level on firm soil and where such elements are wood, they shall be approved pressure preservative treated suitable for ground contact use.

    1.4.  The structure is anchored to withstand wind loads as required by this code.

    1.5.  The structure shall be of light-frame construction whose vertical and horizontal structural elements are primarily formed by a system of repetitive wood or light-gauge steel framing members, with walls and roof of lightweight material, not slate, tile, brick or masonry.

  2. Footings are not required for ramps serving dwelling units in Groups R-3 and R-5 occupancies where the height of the entrance is not more than 30 inches (762 mm) above grade.

TABLE R403.1(1)

MINIMUM WIDTH AND THICKNESS FOR CONCRETE FOOTINGS FOR LIGHT-FRAME CONSTRUCTION (inches)a, b

SNOW LOAD OR ROOF LIVE LOAD STORY AND TYPE OF STRUCTURE WITH LIGHT FRAME LOAD-BEARING VALUE OF SOIL (psf)
1500 2000 2500 3000 3500 4000
20 psf 1 story—slab-on-grade 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 18 × 6 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—slab-on-grade 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—with crawl space 16 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—plus basement 22 × 6 16 × 6 13 × 6 12 × 6 12 × 6 12 × 6
3 story—slab-on-grade 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
3 story—with crawl space 19 × 6 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6
3 story—plus basement 25 × 8 19 × 6 15 × 6 13 × 6 12 × 6 12 × 6
30 psf 1 story—slab-on-grade 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 13 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 19 × 6 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—slab-on-grade 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—with crawl space 17 × 6 13 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—plus basement 23 × 6 17 × 6 14 × 6 12 × 6 12 × 6 12 × 6
3 story—slab-on-grade 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
3 story—with crawl space 20 × 6 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6
3 story—plus basement 26 × 8 20 × 6 16 × 6 13 × 6 12 × 6 12 × 6
50 psf 1 story—slab-on-grade 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 16 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 21 × 6 16 × 6 13 × 6 12 × 6 12 × 6 12 × 6
2 story—slab-on-grade 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—with crawl space 19 × 6 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—plus basement 25 × 7 19 × 6 15 × 6 12 × 6 12 × 6 12 × 6
3 story—slab-on-grade 17 × 6 13 × 6 12 × 6 12 × 6 12 × 6 12 × 6
3 story—with crawl space 22 × 6 17 × 6 13 × 6 12 × 6 12 × 6 12 × 6
3 story—plus basement 28 × 9 21 × 6 17 × 6 14 × 6 12 × 6 12 × 6
70 psf 1 story—slab-on-grade 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 18 × 6 13 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 24 × 7 18 × 6 14 × 6 12 × 6 12 × 6 12 × 6
2 story—slab-on-grade 16 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—with crawl space 21 × 6 16 × 6 13 × 6 12 × 6 12 × 6 12 × 6
2 story—plus basement 27 × 9 20 × 6 16 × 6 14 × 6 12 × 6 12 × 6
3 story—slab-on-grade 19 × 6 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6
3 story—with crawl space 25 × 7 18 × 6 15 × 6 12 × 6 12 × 6 12 × 6
3 story—plus basement 30 × 10 23 × 6 18 × 6 15 × 6 13 × 6 12 × 6

For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.

  1. Interpolation allowed. Extrapolation is not allowed.
  2. Based on 32-foot-wide house with load-bearing center wall that carries half of the tributary attic, and floor framing. For every 2 feet of adjustment to the width of the house, add or subtract 2 inches of footing width and 1 inch of footing thickness (but not less than 6 inches thick).

TABLE R403.1(2)

MINIMUM WIDTH AND THICKNESS FOR CONCRETE FOOTINGS FOR LIGHT-FRAME CONSTRUCTION WITH BRICK VENEER (inches)a, b

SNOW LOAD OR ROOF LIVE LOAD STORY AND TYPE OF STRUCTURE WITH BRICK VENEER LOAD-BEARING VALUE OF SOIL (psf)
1500 2000 2500 3000 3500 4000
20 psf 1 story—slab-on-grade 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 21 × 6 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—slab-on-grade 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—with crawl space 20 × 6 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—plus basement 26 × 8 20 × 6 16 × 6 13 × 6 12 × 6 12 × 6
3 story—slab-on-grade 20 × 6 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6
3 story—with crawl space 26 × 8 19 × 6 15 × 6 13 × 6 12 × 6 12 × 6
3 story—plus basement 32 × 11 24 × 7 19 × 6 16 × 6 14 × 6 12 × 6
30 psf 1 story—slab-on-grade 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 16 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 22 × 6 16 × 6 13 × 6 12 × 6 12 × 6 12 × 6
2 story—slab-on-grade 16 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—with crawl space 22 × 6 16 × 6 13 × 6 12 × 6 12 × 6 12 × 6
2 story—plus basement 27 × 9 21 × 6 16 × 6 14 × 6 12 × 6 12 × 6
3 story—slab-on-grade 21 × 6 16 × 6 13 × 6 12 × 6 12 × 6 12 × 6
3 story—with crawl space 27 × 8 20 × 6 16 × 6 13 × 6 12 × 6 12 × 6
3 story—plus basement 33 × 11 24 × 7 20 × 6 16 × 6 14 × 6 12 × 6
50 psf 1 story—slab-on-grade 13 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 18 × 6 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 24 × 7 18 × 6 14 × 6 12 × 6 12 × 6 12 × 6
2 story—slab-on-grade 18 × 6 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—with crawl space 24 × 7 18 × 6 14 × 6 12 × 6 12 × 6 12 × 6
2 story—plus basement 29 × 10 22 × 6 18 × 6 15 × 6 13 × 6 12 × 6
3 story—slab-on-grade 27 × 7 18 × 6 13 × 6 12 × 6 12 × 6 12 × 6
3 story—with crawl space 29 × 9 22 × 6 17 × 6 14 × 6 12 × 6 12 × 6
3 story—plus basement 35 × 12 26 × 8 21 × 6 17 × 6 15 × 6 13 × 6
70 psf 1 story—slab-on-grade 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 20 × 6 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 26 × 8 20 × 6 16 × 6 13 × 6 12 × 6 12 × 6
2 story—slab-on grade 20 × 6 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6
2 story—with crawl space 26 × 8 19 × 6 15 × 6 13 × 6 12 × 6 12 × 6
2 story—plus basement 32 × 11 24 × 7 19 × 6 16 × 6 14 × 6 12 × 6
3 story—slab-on-grade 26 × 8 19 × 6 15 × 6 13 × 6 12 × 6 12 × 6
3 story—with crawl space 31 × 11 23 × 7 19 × 6 16 × 6 13 × 6 12 × 6
3 story—plus basement 37 × 13 28 × 9 22 × 6 18 × 6 16 × 6 14 × 6

For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.

  1. Interpolation allowed. Extrapolation is not allowed.
  2. Based on 32-foot-wide house with load-bearing center wall that carries half of the tributary attic, and floor framing. For every 2 feet of adjustment to the width of the house, add or subtract 2 inches of footing width and 1 inch of footing thickness (but not less than 6 inches thick).

TABLE R403.1(3)

MINIMUM WIDTH AND THICKNESS FOR CONCRETE FOOTINGS WITH CAST-IN-PLACE CONCRETE OR FULLY GROUTED MASONRY WALL CONSTRUCTION (inches)a, b

SNOW LOAD OR ROOF LIVE LOAD STORY AND TYPE OF STRUCTURE WITH CMU LOAD-BEARING VALUE OF SOIL (psf)
1500 2000 2500 3000 3500 4000
20 psf 1 story—slab-on-grade 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 19 × 6 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 25 × 8 19 × 6 15 × 6 13 × 6 12 × 6 12 × 6
2 story—slab-on-grade 23 × 7 18 × 6 14 × 6 12 × 6 12 × 6 12 × 6
2 story—with crawl space 29 × 9 22 × 6 17 × 6 14 × 6 12 × 6 12 × 6
2 story—plus basement 35 × 12 26 × 8 21 × 6 17 × 6 15 × 6 13 × 6
3 story—slab-on-grade 32 × 11 24 × 7 19 × 6 16 × 6 14 × 6 12 × 6
3 story—with crawl space 38 × 14 28 × 9 23 × 6 19 × 6 16 × 6 14 × 6
3 story—plus basement 43 × 17 33 × 11 26 × 8 22 × 6 19 × 6 16 × 6
30 psf 1 story—slab-on-grade 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 20 × 6 15 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 26 × 8 20 × 6 16 × 6 13 × 6 12 × 6 12 × 6
2 story—slab-on-grade 24 × 7 18 × 6 15 × 6 12 × 6 12 × 6 12 × 6
2 story—with crawl space 30 × 10 22 × 6 18 × 6 15 × 6 13 × 6 12 × 6
2 story—plus basement 36 × 13 27 × 8 21 × 6 18 × 6 15 × 6 13 × 6
3 story—slab-on-grade 33 × 12 25 × 7 20 × 6 17 × 6 14 × 6 12 × 6
3 story—with crawl space 39 × 14 29 × 9 23 × 7 19 × 6 17 × 6 14 × 6
3 story—plus basement 44 × 17 33 × 12 27 × 8 22 × 6 19 × 6 17 × 6
50 psf 1 story—slab-on-grade 17 × 6 13 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 22 × 6 17 × 6 13 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 28 × 9 21 × 6 17 × 6 14 × 6 12 × 6 12 × 6
2 story—slab-on-grade 27 × 8 20 × 6 16 × 6 13 × 6 12 × 6 12 × 6
2 story—with crawl space 32 × 11 24 × 7 19 × 6 16 × 6 14 × 6 12 × 6
2 story—plus basement 38 × 14 28 × 9 23 × 6 19 × 6 16 × 6 14 × 6
3 story—slab-on-grade 35 × 13 27 × 8 21 × 6 18 × 6 15 × 6 13 × 6
3 story—with crawl space 41 × 15 31 × 10 24 × 7 20 × 6 17 × 6 15 × 6
3 story—plus basement 47 × 18 35 × 12 28 × 9 23 × 7 20 × 6 17 × 6
70 psf 1 story—slab-on-grade 19 × 6 14 × 6 12 × 6 12 × 6 12 × 6 12 × 6
1 story—with crawl space 25 × 7 18 × 6 15 × 6 12 × 6 12 × 6 12 × 6
1 story—plus basement 30 × 10 23 × 6 18 × 6 15 × 6 13 × 6 12 × 6
2 story—slab-on-grade 29 × 9 22 × 6 17 × 6 14 × 6 12 × 6 12 × 6
2 story—with crawl space 34 × 12 26 × 8 21 × 6 17 × 6 15 × 6 13 × 6
2 story—plus basement 40 × 15 30 × 10 24 × 7 20 × 6 17 × 6 15 × 6
3 story—slab-on-grade 38 × 14 28 × 9 23 × 6 19 × 6 16 × 6 14 × 6
3 story—with crawl space 43 × 16 32 × 11 26 × 8 21 × 6 18 × 6 16 × 6
3 story—plus basement 49 × 19 37 × 13 29 × 10 24 × 7 21 × 6 18 × 6

For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.

  1. Interpolation allowed. Extrapolation is not allowed.
  2. Based on 32-foot-wide house with load-bearing center wall that carries half of the tributary attic, and floor framing. For every 2 feet of adjustment to the width of the house add or subtract 2 inches of footing width and 1 inch of footing thickness (but not less than 6 inches thick).

For SI: 1 inch = 25.4 mm.

W = Width of footing, T = Thickness of footing and P = Projection per Section R403.1.1

NOTES:

  1. See Section R404.3 for sill requirements.
  2. See Section R403.1.6 for sill attachment.
  3. See Section R506.2.3 for vapor barrier requirements.
  4. See Section R403.1 for base.
  5. See Figure R403.1.3 for additional footing requirements for structures in SDC D0, D1 and D2 and townhouses in SDC C.
  6. See Section R408 for under-floor ventilation and access requirements.

FIGURE R403.1(1)

 PLAIN CONCRETE FOOTINGS WITH MASONRY AND CONCRETE STEM WALLS IN SDC A, B AND Ca, b, c, d, e, f

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

FIGURE R403.1(2)

 PERMANENT WOOD FOUNDATION BASEMENT WALL SECTION

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

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. The footing width shall be based on the load-bearing value of the soil in accordance with Table R401.4.1. 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. 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).

Exterior walls of buildings located in Seismic Design Categories D0, D1 and D2 shall be supported by continuous solid or fully grouted masonry or concrete footings. Other footing materials or systems shall be designed in accordance with accepted engineering practice. Required interior braced wall panels in buildings located in Seismic Design Categories D0, D1 and D2 with plan dimensions greater than 50 feet (15 240 mm) shall be supported by continuous solid or fully grouted masonry or concrete footings in accordance with Section R403.1.3.4, except for two-story buildings in Seismic Design Category D2, in which all braced wall panels, interior and exterior, shall be supported on continuous foundations.

Exception: Two-story buildings shall be permitted to have interior braced wall panels supported on continuous foundations at intervals not exceeding 50 feet (15 240 mm) provided that:

  1. The height of cripple walls does not exceed 4 feet (1219 mm).
  2. First-floor braced wall panels are supported on doubled floor joists, continuous blocking or floor beams.
  3. The distance between bracing lines does not exceed twice the building width measured parallel to the braced wall line.

Concrete footings located in Seismic Design Categories D0, D1 and D2, as established in Table R301.2(1), shall have minimum reinforcement in accordance with this section and Figure R403.1.3. Reinforcement shall be installed with support and cover in accordance with Section R403.1.3.5.

W = Width of footing, T = Thickness of footing and P = Projection per Section R403.1.1

NOTES:

  1. See Section R404.3 for sill requirements.
  2. See Section R403.1.6 for sill attachment.
  3. See Section R506.2.3 for vapor barrier requirements.
  4. See Section R403.1 for base.
  5. See Section R408 for under-floor ventilation and access requirements.
  6. See Section R403.1.3.5 for reinforcement requirements.

FIGURE R403.1.3

 REINFORCED CONCRETE FOOTINGS AND MASONRY AND CONCRETE STEM WALLS IN SDC D0, D1 AND D2a, b, c, d, e, f,

In Seismic Design Categories D0, D1 and D2 where a construction joint is created between a concrete footing and a concrete stem wall, not fewer than one No. 4 vertical bar shall be installed at not more than 4 feet (1219 mm) on center. The vertical bar shall have a standard hook and extend to the bottom of the footing and shall have support and cover as specified in Section R403.1.3.5.3 and extend not less than 14 inches (357 mm) into the stem wall. Standard hooks shall comply with Section R608.5.4.5. Not fewer than one No. 4 horizontal bar shall be installed within 12 inches (305 mm) of the top of the stem wall and one No. 4 horizontal bar shall be located 3 to 4 inches (76 mm to 102 mm) from the bottom of the footing.
In Seismic Design Categories D0, D1 and D2 where a masonry stem wall is supported on a concrete footing, not fewer than one No. 4 vertical bar shall be installed at not more than 4 feet (1219 mm) on center. The vertical bar shall have a standard hook and extend to the bottom of the footing and shall have support and cover as specified in Section R403.1.3.5.3 and extend not less than 14 inches (357 mm) into the stem wall. Standard hooks shall comply with Section R608.5.4.5. Not fewer than one No. 4 horizontal bar shall be installed within 12 inches (305 mm) of the top of the wall and one No. 4 horizontal bar shall be located 3 to 4 inches (76 mm to 102 mm) from the bottom of the footing. Masonry stem walls shall be solid grouted.

In Seismic Design Categories D0, D1 and D2, slabs-on-ground cast monolithically with turned-down footings shall have not fewer than one No. 4 bar at the top and the bottom of the footing or one No. 5 bar or two No. 4 bars in the middle third of the footing depth.

Where the slab is not cast monolithically with the footing, No. 3 or larger vertical dowels with standard hooks on each end shall be installed at not more than 4 feet (1219 mm) on center in accordance with Figure R403.1.3, Detail 2. Standard hooks shall comply with Section R608.5.4.5.

R403.1.3.4 Interior bearing and braced wall panel footings in Seismic Design Categories D0, D1 and D2. In Seismic Design Categories D0, D1 and D2, interior footings supporting bearing walls or braced wall panels, and cast monolithically with a slab on grade, shall extend to a depth of not less than 12 inches (305 mm) below the top of the slab.

Footing and stem wall reinforcement shall comply with Sections R403.1.3.5.1 through R403.1.3.5.4.
Steel reinforcement shall comply with the requirements of ASTM A615, A706 or A996. ASTM A996 bars produced from rail steel shall be Type R. The minimum yield strength of reinforcing steel shall be 40,000 psi (Grade 40) (276 MPa).
The center of vertical reinforcement in stem walls shall be located at the centerline of the wall. Horizontal and vertical reinforcement shall be located in footings and stem walls to provide the minimum cover required by Section R403.1.3.5.3.
Reinforcement shall be secured in the proper location in the forms with tie wire or other bar support system to prevent displacement during the concrete placement operation. Steel reinforcement in concrete cast against the earth shall have a minimum cover of 3 inches (75 mm). Minimum cover for reinforcement in concrete cast in removable forms that will be exposed to the earth or weather shall be 11/2 inches (38 mm) for No. 5 bars and smaller, and 2 inches (50 mm) for No. 6 bars and larger. For concrete cast in removable forms that will not be exposed to the earth or weather, and for concrete cast in stay-in-place forms, minimum cover shall be 3/4 inch (19 mm).
Vertical and horizontal reinforcement shall be the longest lengths practical. Where splices are necessary in reinforcement, the length of lap splice shall be in accordance with Table R608.5.4.(1) and Figure R608.5.4(1). The maximum gap between noncontact parallel bars at a lap splice shall not exceed the smaller of one-fifth the required lap length and 6 inches (152 mm) [see Figure R608.5.4(1)].
In detached one- and two-family dwellings that are three stories or less in height and constructed with stud bearing walls, isolated plain concrete footings supporting columns or pedestals are permitted.
Exterior footings shall be placed not less than 12 inches (305 mm) below the undisturbed ground surface. Where applicable, the depth of footings shall also conform to Section R403.1.4.1.

Except where otherwise protected from frost, foundation walls, piers and other permanent supports of buildings and structures shall be protected from frost by one or more of the following methods:

  1. Extended below the frost line specified in Table R301.2.(1).
  2. Constructed in accordance with Section R403.3.
  3. Constructed in accordance with ASCE 32.
  4. Erected on solid rock.

Footings shall not bear on frozen soil unless the frozen condition is permanent.

Exceptions:

  1. Protection of free-standing accessory structures with an area of 600 square feet (56 m2) or less, of light-frame construction, with an eave height of 10 feet (3048 mm) or less shall not be required.
  2. Protection of free-standing accessory structures with an area of 400 square feet (37 m2) or less, of other than light-frame construction, with an eave height of 10 feet (3048 mm) or less shall not be required.
  3. Decks not supported by a dwelling need not be provided with footings that extend below the frost line.

R403.1.5 Slope

ILLUSTRATION
The top surface of footings shall be level. The bottom surface of footings shall not have a slope exceeding one 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 footings or where the slope of the bottom surface of the footings will exceed one unit vertical in 10 units horizontal (10-percent slope).

Wood sill plates and wood walls supported directly on continuous foundations shall be anchored to the foundation in accordance with this section.

Cold-formed steel framing shall be anchored directly to the foundation or fastened to wood sill plates in accordance with Section R505.3.1 or R603.3.1, as applicable. Wood sill plates supporting cold-formed steel framing shall be anchored to the foundation in accordance with this section.

Wood foundation plates or sills shall be bolted or anchored to the foundation with not less than 1/2-inchdiameter (12.7 mm) steel bolts or approved anchors spaced to provide equivalent anchorage as the steel bolts. Bolts shall be embedded not less than 7 inches (178 mm) into concrete or grouted cells of concrete masonry units. The centerline of the bolts shall be located a minimum of 1.75 inches (44.5 mm) from the edge of the sill plate. Bolts shall be spaced not more than 6 feet (1829 mm) on center and there shall be not less than two bolts or anchor straps per piece with one bolt or anchor strap located not more than 12 inches (305 mm) or less than 4 inches (102 mm) from each end of each piece. A properly sized nut and washer shall be tightened on each bolt to the plate. Interior bearing wall sole plates on monolithic slab foundation that are not part of a braced wall panel shall be positively anchored with approved fasteners. Sill plates and sole plates shall be protected against decay and termites where required by Sections R317 and R318.

Exceptions:

  1. Walls 24 inches (610 mm) total length or shorter connecting offset braced wall panels shall be anchored to the foundation with no fewer than one anchor bolt located in the center third of the plate section and shall be attached to adjacent braced wall panels at corners as shown in Item 9 of Table R602.3(1).
  2. Connection of walls 12 inches (305 mm) total length or shorter connecting offset braced wall panels to the foundation without anchor bolts shall be permitted. The wall shall be attached to adjacent braced wall panels at corners as shown in Item 9 of Table R602.3(1).

In addition to the requirements of Section R403.1.6, the following requirements shall apply to wood light-frame structures in Seismic Design Categories D0, D1 and D2 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).
The placement of buildings and structures on or adjacent to slopes steeper than one unit vertical in three units horizontal (33.3-percent slope) shall conform to Sections R403.1.7.1 through R403.1.7.4.

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 one unit vertical in one 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.

FIGURE R403.1.7.1

 FOUNDATION CLEARANCE FROM SLOPES

For SI: 1 foot = 304.8 mm.

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 one unit vertical in one 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.
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.
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.

Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1808.6 of the International 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.

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 µm), 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.
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).

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.

For SI: 1 inch = 25.4 mm.

  1. See Table R403.3(1) for required dimensions and R-values for vertical and horizontal insulation and minimum footing depth.

FIGURE R403.3(1)

 INSULATION PLACEMENT FOR FROST-PROTECTED FOOTINGS IN HEATED BUILDINGS

TABLE R403.3(1)

MINIMUM FOOTING DEPTH AND INSULATION REQUIREMENTS FOR FROST-PROTECTED FOOTINGS IN HEATED BUILDINGSa

AIR FREEZING INDEX (°F-days)b MINIMUM FOOTING DEPTH, D (inches) VERTICAL INSULATION R-VALUEc, d HORIZONTAL INSULATION R-VALUEc, e HORIZONTAL INSULATION DIMENSIONS PER Figure R403.3(1) (inches)
Along walls At corners A B C
1,500 or less 12 4.5 Not required Not required Not required Not required Not required
2,000 14 5.6 Not required Not required Not required Not required Not required
2,500 16 6.7 1.7 4.9 12 24 40
3,000 16 7.8 6.5 8.6 12 24 40
3,500 16 9.0 8.0 11.2 24 30 60
4,000 16 10.1 10.5 13.1 24 36 60

For SI: 1 inch = 25.4 mm, °C = [(°F) - 32]/1.8.

  1. Insulation requirements are for protection against frost damage in heated buildings. Greater values could be required to meet energy conservation standards.
  2. See Figure R403.3(2) or Table R403.3(2) for Air Freezing Index values.
  3. Insulation materials shall provide the stated minimum R-values under long-term exposure to moist, below-ground conditions in freezing climates. The following R-values shall be used to determine insulation thicknesses required for this application: Type II expanded polystyrene (EPS)-3.2 R per inch for vertical insulation and 2.6 R per inch for horizontal insulation; Type IX expanded polystyrene (EPS)-3.4 R per inch for vertical insulation and 2.8 R per inch for horizontal insulation; Types IV, V, VI, VII, and X extruded polystyrene (XPS)-4.5 R per inch for vertical insulation and 4.0 R per inch for horizontal insulation.
  4. Vertical insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.
  5. Horizontal insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.

For SI: °C = [(°F) -32]/1.8.

Note: The air-freezing index is defined as cumulative degree days below 32°F. It is used as a measure of the combined magnitude and duration of air temperature below freezing. The index was computed over a 12-month period (July-June) for each of the 3,044 stations used in the above analysis. Dates from the 1951-80 period were fitted to a Weibull probability distribution to produce an estimate of the 100-year return period.

FIGURE R403.3(2)

 AIR-FREEZING INDEX AN ESTIMATE OF THE 100-YEAR RETURN PERIOD

TABLE R403.3(2)

AIR-FREEZING INDEX FOR U.S. LOCATIONS BY COUNTY

STATE AIR-FREEZING INDEX
1500 or less 2000 2500 3000 3500 4000
Alabama All counties
Alaska Ketchikan Gateway, Prince of Wales-Outer Ketchikan (CA), Sitka, Wrangell-Petersburg (CA) Aleutians West (CA), Haines, Juneau, Skagway-Hoonah-Angoon (CA), Yakutat All counties not listed
Arizona All counties
Arkansas All counties
California All counties not listed Nevada, Sierra
Colorado All counties not listed Archuleta, Custer, Fremont, Huerfano, Las Animas, Ouray, Pitkin, San Miguel Clear Creek, Conejos, Costilla, Dolores, Eagle, La Plata, Park, Routt, San Juan, Summit Alamosa, Grand, Jackson, Larimer, Moffat, Rio Blanco, Rio Grande Chaffee, Gunnison, Lake, Saguache Hinsdale, Mineral
Connecticut All counties not listed Hartford, Litchfield
Delaware All counties
District of Columbia All counties
Florida All counties
Georgia All counties
Hawaii All counties
Idaho All counties not listed Adams, Bannock, Blaine, Clearwater, Idaho, Lincoln, Oneida, Power, Valley, Washington Bingham, Bonneville, Camas, Caribou, Elmore, Franklin, Jefferson, Madison, Teton Bear Lake, Butte, Custer, Fremont, Lemhi Clark
Illinois All counties not listed Boone, Bureau, Cook, Dekalb, DuPage, Fulton, Grundy, Henderson, Henry, Iroquois, Jo Daviess, Kane, Kankakee, Kendall, Knox, La Salle, Lake, Lee, Livingston, Marshall, Mason, McHenry, McLean, Mercer, Peoria, Putnam, Rock Island, Stark, Tazewell, Warren, Whiteside, Will, Woodford Carroll, Ogle, Stephenson, Winnebago
Indiana All counties not listed Allen, Benton, Cass, Fountain, Fulton, Howard, Jasper, Kosciusko, La Porte, Lake, Marshall, Miami, Newton, Porter, Pulaski, Starke, Steuben, Tippecanoe, Tipton, Wabash, Warren, White
Iowa Appanoose, Davis, Fremont, Lee, Van Buren All counties not listed Allamakee, Black Hawk, Boone, Bremer, Buchanan, Buena Vista, Butler, Calhoun, Cerro Gordo, Cherokee, Chickasaw, Clay, Clayton, Delaware, Dubuque, Fayette, Floyd, Franklin, Grundy, Hamilton, Hancock, Hardin, Humboldt, Ida, Jackson, Jasper, Jones, Linn, Marshall, Palo Alto, Plymouth, Pocahontas, Poweshiek, Sac, Sioux, Story, Tama, Webster, Winnebago, Woodbury, Worth, Wright Dickinson, Emmet, Howard, Kossuth, Lyon, Mitchell, O'Brien, Osceola, Winneshiek
Kansas All counties
Kentucky All counties
Louisiana All counties
Maine York Knox, Lincoln, Sagadahoc Androscoggin, Cumberland, Hancock, Kennebec, Waldo, Washington Aroostook, Franklin, Oxford, Penobscot, Piscataquis, Somerset
Maryland All counties
Massachusetts All counties not listed Berkshire, Franklin, Hampden, Worcester
Michigan Berrien, Branch, Cass, Kalamazoo, Macomb, Ottawa, St. Clair, St. Joseph All counties not listed Alger, Charlevoix, Cheboygan, Chippewa, Crawford, Delta, Emmet, Iosco, Kalkaska, Lake, Luce, Mackinac, Menominee, Missaukee, Montmorency, Ogemaw, Osceola, Otsego, Roscommon, Schoolcraft, Wexford Baraga, Dickinson, Iron, Keweenaw, Marquette Gogebic, Houghton, Ontonagon
Minnesota Houston, Winona All counties not listed Aitkin, Big Stone, Carlton, Crow Wing, Douglas, Itasca, Kanabec, Lake, Morrison, Pine, Pope, Stearns, Stevens, Swift, Todd, Wadena Becker, Beltrami, Cass, Clay, Clearwater, Grant, Hubbard, Kittson, Koochiching, Lake of the Woods, Mahnomen, Marshall, Norman, Otter Tail, Pennington, Polk, Red Lake, Roseau, St. Louis, Traverse, Wilkin
Mississippi All counties
Missouri All counties not listed Atchison, Mercer, Nodaway, Putnam
Montana Mineral Broadwater, Golden Valley, Granite, Lake, Lincoln, Missoula, Ravalli, Sanders, Sweet Grass Big Horn, Carbon, Jefferson, Judith Basin, Lewis and Clark, Meagher, Musselshell, Powder River, Powell, Silver Bow, Stillwater, Westland Carter, Cascade, Deer Lodge, Falcon, Fergus, Flathead, Gallatin, Glacier, Madison, Park, Petroleum, Ponder, Rosebud, Teton, Treasure, Yellowstone Beaverhead, Blaine, Chouteau, Custer, Dawson, Garfield, Liberty, McCone, Prairie, Toole, Wibaux Daniels, Hill, Phillips, Richland, Roosevelt, Sheridan, Valley
Nebraska Adams, Banner, Chase, Cheyenne, Clay, Deuel, Dundy, Fillmore, Franklin, Frontier, Furnas, Gage, Garden, Gosper, Harlan, Hayes, Hitchcock, Jefferson, Kimball, Morrill, Nemaha, Nuckolls, Pawnee, Perkins, Phelps, Red Willow, Richardson, Saline, Scotts Bluff, Seward, Thayer, Webster All counties not listed Boyd, Burt, Cedar, Cuming, Dakota, Dixon, Dodge, Knox, Thurston
Nevada All counties not listed Elko, Eureka, Nye, Washoe, White Pine
New Hampshire All counties not listed Carroll, Coos, Grafton
New Jersey All counties
New Mexico All counties not listed Rio Arriba Colfax, Mora, Taos
New York Albany, Bronx, Cayuga, Columbia, Cortland, Dutchess, Genessee, Kings, Livingston, Monroe, Nassau, New York, Niagara, Onondaga, Ontario, Orange, Orleans, Putnam, Queens, Richmond, Rockland, Seneca, Suffolk, Wayne, Westchester, Yates All counties not listed Clinton, Essex, Franklin, Hamilton, Herkimer, Jefferson, Lewis, St. Lawrence, Warren
North Carolina All counties
North Dakota Billings, Bowman Adams, Dickey, Golden Valley, Hettinger, LaMoure, Oliver, Ransom, Sargent, Sioux, Slope, Stark All counties not listed
Ohio All counties not listed Ashland, Crawford, Defiance, Holmes, Huron, Knox, Licking, Morrow, Paulding, Putnam, Richland, Seneca, Williams
Oklahoma All counties
Oregon All counties not listed Baker, Crook, Grant, Harney
Pennsylvania All counties not listed Berks, Blair, Bradford, Cambria, Cameron, Centre, Clarion, Clearfield, Clinton, Crawford, Elk, Forest, Huntingdon, Indiana, Jefferson, Lackawanna, Lycoming, McKean, Pike, Potter, Susquehanna, Tioga, Venango, Warren, Wayne, Wyoming
Rhode Island All counties
South Carolina All counties
South Dakota Bennett, Custer, Fall River, Lawrence, Mellette, Shannon, Todd, Tripp Bon Homme, Charles Mix, Davison, Douglas, Gregory, Jackson, Jones, Lyman All counties not listed Beadle, Brookings, Brown, Campbell, Codington, Corson, Day, Deuel, Edmunds, Faulk, Grant, Hamlin, Kingsbury, Marshall, McPherson, Perkins, Roberts, Spink, Walworth
Tennessee All counties
Texas All counties
Utah All counties not listed Box Elder, Morgan, Weber Garfield, Salt Lake, Summit Carbon, Daggett, Duchesne, Rich, Sanpete, Uintah, Wasatch
Vermont Bennington, Grand Isle, Rutland, Windham Addison, Chittenden, Franklin, Orange, Washington, Windsor Caledonia, Essex, Lamoille, Orleans
Virginia All counties
Washington All counties not listed Chelan, Douglas, Ferry, Okanogan
West Virginia All counties
Wisconsin Kenosha, Kewaunee, Racine, Sheboygan, Walworth All counties not listed Ashland, Barron, Burnett, Chippewa, Clark, Dunn, Eau Claire, Florence, Forest, Iron, Jackson, La Crosse, Langlade, Marathon, Monroe, Pepin, Polk, Portage, Price, Rust, St. Croix, Taylor, Trempealeau, Vilas, Wood Bayfield, Douglas, Lincoln, Oneida, Sawyer, Washburn
Wyoming Goshen, Platte Converse, Crook, Laramie, Niobrara Campbell, Carbon, Hot Springs, Johnson, Natrona, Sheridan, Uinta, Weston Albany, Big Horn, Park, Washakie Fremont, Teton Lincoln, Sublette, Sweetwater

For SI: 1 inch = 25.4 mm.

  1. See Table R403.3(1) for required dimensions and R-values for vertical and horizontal insulation.

FIGURE R403.3(3)

 INSULATION PLACEMENT FOR FROST-PROTECTED FOOTINGS ADJACENT TO UNHEATED SLAB-ON-GROUND STRUCTURE

FIGURE R403.3(4)

 INSULATION PLACEMENT FOR FROST-PROTECTED FOOTINGS ADJACENT TO HEATED STRUCTURE

Foundations that adjoin frost-protected shallow foundations shall be protected from frost in accordance with Section R403.1.4.
Vertical wall insulation and horizontal insulation of frost-protected shallow foundations that adjoin a slab-on-ground foundation that does not have a monthly mean temperature maintained at not less than 64°F (18°C) shall be in accordance with Figure R403.3(3) and Table R403.3(1). Vertical wall insulation shall extend between the frost-protected shallow foundation and the adjoining slab foundation. Required horizontal insulation shall be continuous under the adjoining slab foundation and through any foundation walls adjoining the frost- protected shallow foundation. Where insulation passes through a foundation wall, it shall be either of a type complying with this section and having bearing capacity equal to or greater than the structural loads imposed by the building, or the building shall be designed and constructed using beams, lintels, cantilevers or other means of transferring building loads such that the structural loads of the building do not bear on the insulation.

Where a frost-protected shallow foundation abuts a structure that has a monthly mean temperature maintained at not less than 64°F (18°C), horizontal insulation and vertical wall insulation shall not be required between the frost-protected shallow foundation and the adjoining structure. Where the frost-protected shallow foundation abuts the heated structure, the horizontal insulation and vertical wall insulation shall extend along the adjoining foundation in accordance with Figure R403.3(4) a distance of not less than Dimension A in Table R403.3(1).

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.

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.
Final grade shall be sloped in accordance with Section R401.3. In other than Group I Soils, as detailed in Table R405.1, gravel or crushed stone beneath horizontal insulation below ground shall drain to daylight or into an approved sewer system.
The use of foam plastic in areas of "very heavy" termite infestation probability shall be in accordance with Section R318.4.

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

FIGURE R403.4(1)

 BASEMENT OR CRAWL SPACE WITH PRECAST FOUNDATION WALL BEARING ON CRUSHED STONE

FIGURE R403.4(2)

 BASEMENT OR CRAWL SPACE WITH PRECAST FOUNDATION WALL ON SPREAD FOOTING

TABLE R403.4

MINIMUM DEPTH (D) AND WIDTH (W) OF CRUSHED STONE FOOTINGSa, b(inches)

NUMBER OF STORIES UNIFORM WALL LOAD DEPTH (D) ANDWIDTH (W) LOAD-BEARING VALUE OF SOIL (psf)
1500 2000 2500 3000 3500 4000
MH, CH, CL, MLc SC, GC, SM, GM, SP, SWc GP, GWc
Wall width (Inches) Wall width (inches) Wall width (inches) Wall width (inches) Wall width (inches) Wall width (inches)
8 10 12 8 10 12 8 10 12 8 10 12 8 10 12 8 10 12
Conventional light-frame construction
1-story 1100 plf D 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4
W 13 15 17 13 15 17 13 15 17 13 15 17 13 15 17 13 15 17
2-story 1800 plf D 6 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4
W 15 15 17 13 15 17 13 15 17 13 15 17 13 15 17 13 15 17
3-story 2900 plf D 14 12 10 9 7 5 6 4 4 4 4 4 4 4 4 4 4 4
W 25 24 24 19 19 18 15 15 17 13 15 17 13 15 17 13 15 17
4-inch brick veneer over light-frame or 8-inch hollow concrete masonry
1-story 1500 plf D 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4
W 13 15 17 13 15 17 13 15 17 13 15 17 13 15 17 13 15 17
2-story 2700 plf D 12 11 9 8 6 4 5 4 4 4 4 4 4 4 4 4 4 4
W 22 23 23 18 17 17 14 15 17 13 15 17 13 15 17 13 15 17
3-story 4000 plf D 21 20 18 14 13 11 10 8 7 7 6 4 5 4 4 4 4 4
W 33 34 33 25 26 25 20 20 21 17 17 17 14 15 17 13 15 17
8-inch solid or fully grouted masonry
1-story 2000 plf D 7 6 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4
W 17 17 17 13 15 17 13 15 17 13 15 17 13 15 17 13 15 17
2-story 3600 plf D 19 17 15 12 11 9 9 7 5 6 4 4 4 4 4 4 4 4
W 30 30 30 22 23 23 19 19 18 15 15 17 13 15 17 13 15 17
3-story 5300 plf D 30 29 27 21 19 18 16 14 12 12 10 8 9 8 6 7 6 4
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.

  1. Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).
  2. Crushed stone must be consolidated in 8-inch lifts with a plate vibrator.
  3. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R404.5.1.
Clean crushed stone shall be free from organic, clayey or silty soils. Crushed stone shall be angular in nature and meet ASTM C33, with the maximum size stone not to exceed 1/2 inch (12.7 mm) and the minimum stone size not to be smaller than 1/16 inch (1.6 mm). Crushed stone footings for precast foundations shall be installed in accordance with Figure R403.4(1) and Table R403.4. Crushed stone footings shall be consolidated using a vibratory plate in not greater than 8-inch (203 mm) lifts. Crushed stone footings shall be limited to Seismic Design Categories A, B and C.
Concrete footings shall be installed in accordance with Section R403.1 and Figure R403.4(2).
Concrete foundation walls shall be selected and constructed in accordance with the provisions of Section R404.1.3. Masonry foundation walls shall be selected and constructed in accordance with the provisions of Section R404.1.2.

Concrete or masonry foundation walls shall be designed in accordance with accepted engineering practice where either of the following conditions exists:

  1. Walls are subject to hydrostatic pressure from ground water.
  2. Walls supporting more than 48 inches (1219 mm) of unbalanced backfill that do not have permanent lateral support at the top or bottom.

TABLE R404.1.1(1)

PLAIN MASONRY FOUNDATION WALLSf

MAXIMUM WALL HEIGHT (feet) MAXIMUM UNBALANCED BACKFILL HEIGHTc (feet) PLAIN MASONRYa MINIMUM NOMINAL WALL THICKNESS (inches)
Soil classesb
GW, GP, SW and SP GM, GC, SM, SM-SC and ML SC, MH, ML-CL and inorganic CL
5 4 6 solidd or 8 6 solidd or 8 6 solidd or 8
5 6 solidd or 8 8 10
6 4 6 solidd or 8 6 solidd or 8 6 solidd or 8
5 6 solidd or 8 8 10
6 8 10 12
7 4 6 solidd or 8 8 8
5 6 solidd or 8 10 10
6 10 12 10 solidd
7 12 10 solidd 12 solidd
8 4 6 solidd or 8 6 solidd or 8 8
5 6 solidd or 8 10 12
6 10 12 12 solidd
7 12 12 solidd Footnote e
8 10 groutd 12 groutd Footnote e
9 4 6 groutd or 8 solidd or 12 6 groutd or 8 solidd 8 groutd or 10 solidd
5 6 groutd or 10 solidd 8 groutd or 12 solidd 8 groutd
6 8 groutd or 12 solidd 10 groutd 10 groutd
7 10 groutd 10 groutd 12 grout
8 10 groutd 12 grout Footnote e
9 12 grout Footnote e Footnote e

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 Pa.

  1. Mortar shall be Type M or S and masonry shall be laid in running bond. Ungrouted hollow masonry units are permitted except where otherwise indicated.
  2. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
  3. Unbalanced backfill height is the difference in height between the exterior finish ground level and the lower of the top of the concrete footing that supports the foundation wall or the interior finish ground level. Where an interior concrete slab-on-grade is provided and is in contact with the interior surface of the foundation wall, measurement of the unbalanced backfill height from the exterior finish ground level to the top of the interior concrete slab is permitted.
  4. Solid indicates solid masonry unit; grout indicates grouted hollow units.
  5. Wall construction shall be in accordance with either Table R404.1.1(2), Table R404.1.1(3), Table R404.1.1(4), or a design shall be provided.
  6. The use of this table shall be prohibited for soil classifications not shown.

TABLE R404.1.1(2)

8-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d ≥ 5 INCHESa, c, f

WALL HEIGHT HEIGHT OF UNBALANCED BACKFILLe MINIMUM VERTICAL REINFORCEMENT AND SPACING (INCHES)b, c
Soil classes and lateral soil loadd (psf per foot below grade)
GW, GP, SW and SP soils 30 GM, GC, SM, SM-SC and ML soils 45 SC, ML-CL and inorganic CL soils 60
6 feet 8 inches 4 feet (or less) #4 at 48 #4 at 48 #4 at 48
5 feet #4 at 48 #4 at 48 #4 at 48
6 feet 8 inches #4 at 48 #5 at 48 #6 at 48
7 feet 4 inches 4 feet (or less) #4 at 48 #4 at 48 #4 at 48
5 feet #4 at 48 #4 at 48 #4 at 48
6 feet #4 at 48 #5 at 48 #5 at 48
7 feet 4 inches #5 at 48 #6 at 48 #6 at 40
8 feet 4 feet (or less) #4 at 48 #4 at 48 #4 at 48
5 feet #4 at 48 #4 at 48 #4 at 48
6 feet #4 at 48 #5 at 48 #5 at 48
7 feet #5 at 48 #6 at 48 #6 at 40
8 feet #5 at 48 #6 at 48 #6 at 32
8 feet 8 inches 4 feet (or less) #4 at 48 #4 at 48 #4 at 48
5 feet #4 at 48 #4 at 48 #5 at 48
6 feet #4 at 48 #5 at 48 #6 at 48
7 feet #5 at 48 #6 at 48 #6 at 40
8 feet 8 inches #6 at 48 #6 at 32 #6 at 24
9 feet 4 inches 4 feet (or less) #4 at 48 #4 at 48 #4 at 48
5 feet #4 at 48 #4 at 48 #5 at 48
6 feet #4 at 48 #5 at 48 #6 at 48
7 feet #5 at 48 #6 at 48 #6 at 40
8 feet #6 at 48 #6 at 40 #6 at 24
9 feet 4 inches #6 at 40 #6 at 24 #6 at 16
10 feet 4 feet (or less) #4 at 48 #4 at 48 #4 at 48
5 feet #4 at 48 #4 at 48 #5 at 48
6 feet #4 at 48 #5 at 48 #6 at 48
7 feet #5 at 48 #6 at 48 #6 at 32
8 feet #6 at 48 #6 at 32 #6 at 24
9 feet #6 at 40 #6 at 24 #6 at 16
10 feet #6 at 32 #6 at 16 #6 at 16

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot per foot = 0.157 kPa/mm.

  1. Mortar shall be Type M or S and masonry shall be laid in running bond.
  2. Alternative reinforcing bar sizes and spacings having an equivalent cross-sectional area of reinforcement per lineal foot of wall shall be permitted provided the spacing of the reinforcement does not exceed 72 inches in Seismic Design Categories A, B and C, and 48 inches in Seismic Design Categories D0, D1 and D2.
  3. Vertical reinforcement shall be Grade 60 minimum. The distance, d, from the face of the soil side of the wall to the center of vertical reinforcement shall be not less than 5 inches.
  4. Soil classes are in accordance with the Unified Soil Classification System and design lateral soil loads are for moist conditions without hydrostatic pressure. Refer to Table R405.1.
  5. Unbalanced backfill height is the difference in height between the exterior finish ground level and the lower of the top of the concrete footing that supports the foundation wall or the interior finish ground level. Where an interior concrete slab-on-grade is provided and is in contact with the interior surface of the foundation wall, measurement of the unbalanced backfill height from the exterior finish ground level to the top of the interior concrete slab is permitted.
  6. The use of this table shall be prohibited for soil classifications not shown.

TABLE R404.1.1(3)

10-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d ≥ 6.75 INCHESa, c, f

WALL HEIGHT HEIGHT OF UNBALANCED BACKFILLe MINIMUM VERTICAL REINFORCEMENT AND SPACING (INCHES)b, c
Soil classes and later soil loadd (psf per foot below grade)
GW, GP, SW and SP soils 30 GM, GC, SM, SM-SC and ML soils 45 SC, ML-CL and inorganic CL soils 60
6 feet 8 inches 4 feet (or less) #4 at 56 #4 at 56 #4 at 56
5 feet #4 at 56 #4 at 56 #4 at 56
6 feet 8 inches #4 at 56 #5 at 56 #5 at 56
7 feet 4 inches 4 feet (or less) #4 at 56 #4 at 56 #4 at 56
5 feet #4 at 56 #4 at 56 #4 at 56
6 feet #4 at 56 #4 at 56 #5 at 56
7 feet 4 inches #4 at 56 #5 at 56 #6 at 56
8 feet 4 feet (or less) #4 at 56 #4 at 56 #4 at 56
5 feet #4 at 56 #4 at 56 #4 at 56
6 feet #4 at 56 #4 at 56 #5 at 56
7 feet #4 at 56 #5 at 56 #6 at 56
8 feet #5 at 56 #6 at 56 #6 at 48
8 feet 8 inches 4 feet (or less) #4 at 56 #4 at 56 #4 at 56
5 feet #4 at 56 #4 at 56 #4 at 56
6 feet #4 at 56 #4 at 56 #5 at 56
7 feet #4 at 56 #5 at 56 #6 at 56
8 feet 8 inches #5 at 56 #6 at 48 #6 at 32
9 feet 4 inches 4 feet (or less) #4 at 56 #4 at 56 #4 at 56
5 feet #4 at 56 #4 at 56 #4 at 56
6 feet #4 at 56 #5 at 56 #5 at 56
7 feet #4 at 56 #5 at 56 #6 at 56
8 feet #5 at 56 #6 at 56 #6 at 40
9 feet 4 inches #6 at 56 #6 at 40 #6 at 24
10 feet 4 feet (or less) #4 at 56 #4 at 56 #4 at 56
5 feet #4 at 56 #4 at 56 #4 at 56
6 feet #4 at 56 #5 at 56 #5 at 56
7 feet #5 at 56 #6 at 56 #6 at 48
8 feet #5 at 56 #6 at 48 #6 at 40
9 feet #6 at 56 #6 at 40 #6 at 24
10 feet #6 at 48 #6 at 32 #6 at 24

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot per foot = 0.157 kPa/mm.

  1. Mortar shall be Type M or S and masonry shall be laid in running bond.
  2. Alternative reinforcing bar sizes and spacings having an equivalent cross-sectional area of reinforcement per lineal foot of wall shall be permitted provided the spacing of the reinforcement does not exceed 72 inches in Seismic Design Categories A, B and C, and 48 inches in Seismic Design Categories D0, D1 and D2.
  3. Vertical reinforcement shall be Grade 60 minimum. The distance, d, from the face of the soil side of the wall to the center of vertical reinforcement shall be not less than 6.75 inches.
  4. Soil classes are in accordance with the Unified Soil Classification System and design lateral soil loads are for moist conditions without hydrostatic pressure. Refer to Table R405.1.
  5. Unbalanced backfill height is the difference in height between the exterior finish ground level and the lower of the top of the concrete footing that supports the foundation wall or the interior finish ground level. Where an interior concrete slab-on-grade is provided and is in contact with the interior surface of the foundation wall, measurement of the unbalanced backfill height from the exterior finish ground level to the top of the interior concrete slab is permitted.
  6. The use of this table shall be prohibited for soil classifications not shown.

TABLE R404.1.1(4)

12-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d ≥ 8.75 INCHESa, c, f

WALL HEIGHT HEIGHT OF UNBALANCED BACKFILLe MINIMUM VERTICAL REINFORCEMENT AND SPACING (INCHES)b, c
Soil classes and lateral soil loadd (psf per foot below grade)
GW, GP, SW and SP soils 30 GM, GC, SM, SM-SC and ML soils 45 SC, ML-CL and inorganic CL soils 60
6 feet 8 inches 4 feet (or less) #4 at 72 #4 at 72 #4 at 72
5 feet #4 at 72 #4 at 72 #4 at 72
6 feet 8 inches #4 at 72 #4 at 72 #5 at 72
7 feet 4 inches 4 feet (or less) #4 at 72 #4 at 72 #4 at 72
5 feet #4 at 72 #4 at 72 #4 at 72
6 feet #4 at 72 #4 at 72 #5 at 72
7 feet 4 inches #4 at 72 #5 at 72 #6 at 72
8 feet 4 feet (or less) #4 at 72 #4 at 72 #4 at 72
5 feet #4 at 72 #4 at 72 #4 at 72
6 feet #4 at 72 #4 at 72 #5 at 72
7 feet #4 at 72 #5 at 72 #6 at 72
8 feet #5 at 72 #6 at 72 #6 at 64
8 feet 8 inches 4 feet (or less) #4 at 72 #4 at 72 #4 at 72
5 feet #4 at 72 #4 at 72 #4 at 72
6 feet #4 at 72 #4 at 72 #5 at 72
7 feet #4 at 72 #5 at 72 #6 at 72
8 feet 8 inches #5 at 72 #7 at 72 #6 at 48
9 feet 4 inches 4 feet (or less) #4 at 72 #4 at 72 #4 at 72
5 feet #4 at 72 #4 at 72 #4 at 72
6 feet #4 at 72 #5 at 72 #5 at 72
7 feet #4 at 72 #5 at 72 #6 at 72
8 feet #5 at 72 #6 at 72 #6 at 56
9 feet 4 inches #6 at 72 #6 at 48 #6 at 40
10 feet 4 feet (or less) #4 at 72 #4 at 72 #4 at 72
5 feet #4 at 72 #4 at 72 #4 at 72
6 feet #4 at 72 #5 at 72 #5 at 72
7 feet #4 at 72 #6 at 72 #6 at 72
8 feet #5 at 72 #6 at 72 #6 at 48
9 feet #6 at 72 #6 at 56 #6 at 40
10 feet #6 at 64 #6 at 40 #6 at 32

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot per foot = 0.157 kPa/mm.

  1. Mortar shall be Type M or S and masonry shall be laid in running bond.
  2. Alternative reinforcing bar sizes and spacings having an equivalent cross-sectional area of reinforcement per lineal foot of wall shall be permitted provided the spacing of the reinforcement does not exceed 72 inches in Seismic Design Categories A, B and C, and 48 inches in Seismic Design Categories D0, D1 and D2.
  3. Vertical reinforcement shall be Grade 60 minimum. The distance, d, from the face of the soil side of the wall to the center of vertical reinforcement shall be not less than 8.75 inches.
  4. Soil classes are in accordance with the Unified Soil Classification System and design lateral soil loads are for moist conditions without hydrostatic pressure. Refer to Table R405.1.
  5. Unbalanced backfill height is the difference in height between the exterior finish ground level and the lower of the top of the concrete footing that supports the foundation wall or the interior finish ground levels. Where an interior concrete slab-on-grade is provided and in contact with the interior surface of the foundation wall, measurement of the unbalanced backfill height is permitted to be measured from the exterior finish ground level to the top of the interior concrete slab is permitted.
  6. The use of this table shall be prohibited for soil classifications not shown.

Masonry foundation walls shall be designed and constructed in accordance with the provisions of this section or in accordance with the provisions of TMS 402. Where TMS 402 or the provisions of this section are used to design masonry foundation walls, project drawings, typical details and specifications are not required to bear the seal of the architect or engineer responsible for design, unless otherwise required by the state law of the jurisdiction having authority.

TABLE R404.1.2(1)

MINIMUM HORIZONTAL REINFORCEMENT FOR CONCRETE BASEMENT WALLSa, b

MAXIMUM UNSUPPORTED HEIGHT OF BASEMENT WALL (feet) LOCATION OF HORIZONTAL REINFORCEMENT
≤ 8 One No. 4 bar within 12 inches of the top of the wall story and one No. 4 bar near mid-height of the wall story.
> 8 One No. 4 bar within 12 inches of the top of the wall story and one No. 4 bar near third points in the wall story.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa.

  1. Horizontal reinforcement requirements are for reinforcing bars with a minimum yield strength of 40,000 psi and concrete with a minimum concrete compressive strength of 2,500 psi.
  2. See Section R404.1.3.2 for minimum reinforcement required for foundation walls supporting above-grade concrete walls.

TABLE R404.1.2(2)

MINIMUM VERTICAL REINFORCEMENT FOR 6-INCH NOMINAL FLAT CONCRETE BASEMENT WALLSb, c, d, e, g, h, i, j, k

MAXIMUM UNSUPPORTED WALL HEIGHT (feet) MAXIMUM UNBALANCED BACKFILL HEIGHTf (feet) MINIMUM VERTICAL REINFORCEMENT-BAR SIZE AND SPACING (inches)
Soil classesa and design lateral soil (psf per foot of depth)
GW, GP, SW, SP 30 GM, GC, SM, SM-SC and ML 45 SC, ML-CL and inorganic CL 60
8 4 NR NR NR
5 NR 6 @ 39 6 @ 48
6 5 @ 39 6 @ 48 6 @ 35
7 6 @ 48 6 @ 34 6 @ 25
8 6 @ 39 6 @ 25 6 @ 18
9 4 NR NR NR
5 NR 5 @ 37 6 @ 48
6 5 @ 36 6 @ 44 6 @ 32
7 6 @ 47 6 @ 30 6 @ 22
8 6 @ 34 6 @ 22 6 @ 16
9 6 @ 27 6 @ 17 DR
10 4 NR NR NR
5 NR 5 @ 35 6 @ 48
6 6 @ 48 6 @ 41 6 @ 30
7 6 @ 43 6 @ 28 6 @ 20
8 6 @ 31 6 @ 20 DR
9 6 @ 24 6 @ 15 DR
10 6 @ 19 DR DR

For SI: 1 inch = 25.4 mm; 1 foot = 304.8 mm; 1 pound per square foot per foot = 0.1571 kPa2/m, 1 pound per square inch = 6.895 kPa.

NR = Not Required.

DR = Design Required.

  1. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
  2. Table values are based on reinforcing bars with a minimum yield strength of 60,000 psi concrete with a minimum specified compressive strength of 2,500 psi and vertical reinforcement being located at the centerline of the wall. See Section R404.1.3.3.7.2.
  3. Vertical reinforcement with a yield strength of less than 60,000 psi and bars of a different size than specified in the table are permitted in accordance with Section R404.1.3.3.7.6 and Table R404.1.2(9).
  4. Deflection criterion is L/240, where L is the height of the basement wall in inches.
  5. Interpolation is not permitted.
  6. Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
  7. NR indicates vertical wall reinforcement is not required, except for 6-inch-nominal walls formed with stay-in-place forming systems in which case vertical reinforcement shall be No. 4@48 inches on center.
  8. See Section R404.1.3.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.
  9. See Table R608.3 for tolerance from nominal thickness permitted for flat walls.
  10. DR means design is required in accordance with the applicable building code, or in the absence of a code, in accordance with ACI 318.
  11. The use of this table shall be prohibited for soil classifications not shown.

TABLE R404.1.2(3)

MINIMUM VERTICAL REINFORCEMENT FOR 8-INCH (203 mm) NOMINAL FLAT CONCRETE BASEMENT WALLSb, c, d, e, f, h, i, j

MAXIMUM UNSUPPORTED WALL HEIGHT (feet) MAXIMUM UNBALANCED BACKFILL HEIGHTg (feet) MINIMUM VERTICAL REINFORCEMENT-BAR SIZE AND SPACING (inches)
Soil classesa and design lateral soil (psf per foot of depth)
GW, GP, SW, SP 30 GM, GC, SM, SM-SC and ML 45 SC, ML-CL and inorganic CL 60
8 4 NR NR NR
5 NR NR NR
6 NR NR 6 @ 37
7 NR 6 @ 36 6 @ 35
8 6 @ 41 6 @ 35 6 @ 26
9 4 NR NR NR
5 NR NR NR
6 NR NR 6 @ 35
7 NR 6 @ 35 6 @ 32
8 6 @ 36 6 @ 32 6 @ 23
9 6 @ 35 6 @ 25 6 @ 18
10 4 NR NR NR
5 NR NR NR
6 NR NR 6 @ 35
7 NR 6 @ 35 6 @ 29
8 6 @ 35 6 @ 29 6 @ 21
9 6 @ 34 6 @ 22 6 @ 16
10 6 @ 27 6 @ 17 6 @ 13

For SI: 1 inch = 25.4 mm; 1 foot = 304.8 mm; 1 pound per square foot per foot = 0.1571 kPa2/m, 1 pound per square inch = 6.895 kPa.

NR = Not Required.

  1. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
  2. Table values are based on reinforcing bars with a minimum yield strength of 60,000 psi, concrete with a minimum specified compressive strength of 2,500 psi and vertical reinforcement being located at the centerline of the wall. See Section R404.1.3.3.7.2.
  3. Vertical reinforcement with a yield strength of less than 60,000 psi and bars of a different size than specified in the table are permitted in accordance with Section R404.1.3.3.7.6 and Table R404.1.2(9).
  4. NR indicates vertical reinforcement is not required.
  5. Deflection criterion is L/240, where L is the height of the basement wall in inches.
  6. Interpolation is not permitted.
  7. Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
  8. See Section R404.1.3.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.
  9. See Table R608.3 for tolerance from nominal thickness permitted for flat walls. j. The use of this table shall be prohibited for soil classifications not shown.

TABLE R404.1.2(4)

MINIMUM VERTICAL REINFORCEMENT FOR 10-INCH NOMINAL FLAT CONCRETE BASEMENT WALLSb, c, d, e, f, h, i, j

MAXIMUM UNSUPPORTED WALL HEIGHT (feet) MAXIMUM UNBALANCED BACKFILL HEIGHTg (feet) MINIMUM VERTICAL REINFORCEMENT-BAR SIZE AND SPACING (inches)
Soil classesa and design lateral soil (psf per foot of depth)
GW, GP, SW, SP 30 GM, GC, SM, SM-SC and ML 45 SC, ML-CL and inorganic CL 60
8 4 NR NR NR
5 NR NR NR
6 NR NR NR
7 NR NR NR
8 6 @ 48 6 @ 35 6 @ 28
9 4 NR NR NR
5 NR NR NR
6 NR NR NR
7 NR NR 6 @ 31
8 NR 6 @ 31 6 @ 28
9 6 @ 37 6 @ 28 6 @ 24
10 4 NR NR NR
5 NR NR NR
6 NR NR NR
7 NR NR 6 @ 28
8 NR 6 @ 28 6 @ 28
9 6 @ 33 6 @ 28 6 @ 21
10 6 @ 28 6 @ 23 6 @ 17

For SI: 1 inch = 25.4 mm; 1 foot = 304.8 mm; 1 pound per square foot per foot = 0.1571 kPa2/m, 1 pound per square inch = 6.895 kPa.

NR = Not Required.

  1. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
  2. Table values are based on reinforcing bars with a minimum yield strength of 60,000 psi concrete with a minimum specified compressive strength of 2,500 psi and vertical reinforcement being located at the centerline of the wall. See Section R404.1.3.3.7.2.
  3. Vertical reinforcement with a yield strength of less than 60,000 psi and bars of a different size than specified in the table are permitted in accordance with Section R404.1.3.3.7.6 and Table R404.1.2(9).
  4. NR indicates vertical reinforcement is not required.
  5. Deflection criterion is L/240, where L is the height of the basement wall in inches.
  6. Interpolation is not permitted.
  7. Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
  8. See Section R404.1.3.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.
  9. See Table R608.3 for tolerance from nominal thickness permitted for flat walls.
  10. The use of this table shall be prohibited for soil classifications not shown.

TABLE R404.1.2(5)

MINIMUM VERTICAL WALL REINFORCEMENT FOR 6-INCH WAFFLE-GRID BASEMENT WALLSb, c, d, e, g, h, i, j

MAXIMUM UNSUPPORTED WALL HEIGHT (feet) MAXIMUM UNBALANCED BACKFILL HEIGHTf (feet) MINIMUM VERTICAL REINFORCEMENT-BAR SIZE AND SPACING (inches)
Soil classesa and design lateral soil (psf per foot of depth)
GW, GP, SW, SP 30 GM, GC, SM, SM-SC and ML 45 SC, ML-CL and inorganic CL 60
8 4 4 @ 48 4 @ 46 6 @ 39
5 4 @ 45 5 @ 46 6 @ 47
6 5 @ 45 6 @ 40 DR
7 6 @ 44 DR DR
8 6 @ 32 DR DR
9 4 4 @ 48 4 @ 46 4 @ 37
5 4 @ 42 5 @ 43 6 @ 44
6 5 @ 41 6 @ 37 DR
7 6 @ 39 DR DR
> 8 DRi DR DR
10 4 4 @ 48 4 @ 46 4 @ 35
5 4 @ 40 5 @ 40 6 @ 41
6 5 @ 38 6 @ 34 DR
7 6 @ 36 DR DR
> 8 DR DR DR

For SI: 1 inch = 25.4 mm; 1 foot = 304.8 mm; 1 pound per square foot per foot = 0.1571 kPa2/m, 1 pound per square inch = 6.895 kPa.

DR = Design Required.

  1. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
  2. Table values are based on reinforcing bars with a minimum yield strength of 60,000 psi concrete with a minimum specified compressive strength of 2,500 psi and vertical reinforcement being located at the centerline of the wall. See Section R404.1.3.3.7.2.
  3. Maximum spacings shown are the values calculated for the specified bar size. Where the bar used is Grade 60 and the size specified in the table, the actual spacing in the wall shall not exceed a whole-number multiple of 12 inches (12, 24, 36 and 48) that is less than or equal to the tabulated spacing. Vertical reinforcement with a yield strength of less than 60,000 psi and bars of a different size than specified in the table are permitted in accordance with Section R404.1.3.3.7.6 and Table R404.1.2(9).
  4. Deflection criterion is L/240, where L is the height of the basement wall in inches.
  5. Interpolation is not permitted.
  6. Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
  7. See Section R404.1.3.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.
  8. See Table R608.3 for thicknesses and dimensions of waffle-grid walls.
  9. DR means design is required in accordance with the applicable building code, or in the absence of a code, in accordance with ACI 318.
  10. The use of this table shall be prohibited for soil classifications not shown.

TABLE R404.1.2(6)

MINIMUM VERTICAL REINFORCEMENT FOR 8-INCH WAFFLE-GRID BASEMENT WALLSb, c, d, e, f, h, i, j, k

MAXIMUM UNSUPPORTED WALL HEIGHT (feet) MAXIMUM UNBALANCED BACKFILL HEIGHTg (feet) MINIMUM VERTICAL REINFORCEMENT-BAR SIZE AND SPACING (inches)
Soil classesa and design lateral soil (psf per foot of depth)
GW, GP, SW, SP 30 GM, GC, SM, SM-SC and ML 45 SC, ML-CL and inorganic CL 60
8 4 NR NR NR
5 NR 5 @ 48 5 @ 46
6 5 @ 48 5 @ 43 6 @ 45
7 5 @ 46 6 @ 43 6 @ 31
8 6 @ 48 6 @ 32 6 @ 23
9 4 NR NR NR
5 NR 5 @ 47 5 @ 46
6 5 @ 46 5 @ 39 6 @ 41
7 5 @ 42 6 @ 38 6 @ 28
8 6 @ 44 6 @ 28 6 @ 20
9 6 @ 34 6 @ 21 DR
10 4 NR NR NR
5 NR 5 @ 46 5 @ 44
6 5 @ 46 5 @ 37 6 @ 38
7 5 @ 38 6 @ 35 6 @ 25
8 6 @ 39 6 @ 25 DR
9 6 @ 30 DR DR
10 6 @ 24 DR DR

For SI: 1 inch = 25.4 mm; 1 foot = 304.8 mm; 1 pound per square foot per foot = 0.1571 kPa2/m, 1 pound per square inch = 6.895 kPa.

NR = Not Required.

DR = Design Required.

  1. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
  2. Table values are based on reinforcing bars with a minimum yield strength of 60,000 psi concrete with a minimum specified compressive strength of 2,500 psi and vertical reinforcement being located at the centerline of the wall. See Section R404.1.3.3.7.2.
  3. Maximum spacings shown are the values calculated for the specified bar size. Where the bar used is Grade 60 (420 MPa) and the size specified in the table, the actual spacing in the wall shall not exceed a whole-number multiple of 12 inches (12, 24, 36 and 48) that is less than or equal to the tabulated spacing. Vertical reinforcement with a yield strength of less than 60,000 psi and bars of a different size than specified in the table are permitted in accordance with Section R404.1.3.3.7.6 and Table R404.1.2(9).
  4. NR indicates vertical reinforcement is not required.
  5. Deflection criterion is L/240, where L is the height of the basement wall in inches.
  6. Interpolation shall not be permitted.
  7. Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
  8. See Section R404.1.3.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.
  9. See Table R608.3 for thicknesses and dimensions of waffle-grid walls.
  10. DR means design is required in accordance with the applicable building code, or in the absence of a code, in accordance with ACI 318.
  11. The use of this table shall be prohibited for soil classifications not shown.

TABLE R404.1.2(7)

MINIMUM VERTICAL REINFORCEMENT FOR 6-INCH (152 mm) SCREEN-GRID BASEMENT WALLSb, c, d, e, g, h, i, j

MAXIMUM UNSUPPORTED WALL HEIGHT (feet) MAXIMUM UNBALANCED BACKFILL HEIGHTf (feet) MINIMUM VERTICAL REINFORCEMENT-BAR SIZE AND SPACING (inches)
Soil classesa and design lateral soil (psf per foot of depth)
GW, GP, SW, SP 30 GM, GC, SM, SM-SC and ML 45 SC, ML-CL and inorganic CL 60
8 4 4 @ 48 4 @ 48 5 @ 43
5 4 @ 48 5 @ 48 5 @ 37
6 5 @ 48 6 @ 45 6 @ 32
7 6 @ 48 DR DR
8 6 @ 36 DR DR
9 4 4 @ 48 4 @ 48 4 @ 41
5 4 @ 48 5 @ 48 6 @ 48
6 5 @ 45 6 @ 41 DR
7 6 @ 43 DR DR
> 8 DR DR DR
10 4 4 @ 48 4 @ 48 4 @ 39
5 4 @ 44 5 @ 44 6 @ 46
6 5 @ 42 6 @ 38 DR
7 6 @ 40 DR DR
> 8 DR DR DR

For SI: 1 inch = 25.4 mm; 1 foot = 304.8 mm; 1 pound per square foot per foot = 0.1571 kPa2/m, 1 pound per square inch = 6.895 kPa.

DR = Design Required.

  1. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
  2. Table values are based on reinforcing bars with a minimum yield strength of 60,000 psi, concrete with a minimum specified compressive strength of 2,500 psi and vertical reinforcement being located at the centerline of the wall. See Section R404.1.3.3.7.2.
  3. Maximum spacings shown are the values calculated for the specified bar size. Where the bar used is Grade 60 and the size specified in the table, the actual spacing in the wall shall not exceed a whole-number multiple of 12 inches (12, 24, 36 and 48) that is less than or equal to the tabulated spacing. Vertical reinforcement with a yield strength of less than 60,000 psi and bars of a different size than specified in the table are permitted in accordance with Section R404.1.3.3.7.6 and Table R404.1.2(9).
  4. Deflection criterion is L/240, where L is the height of the basement wall in inches.
  5. Interpolation is not permitted.
  6. Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
  7. See Sections R404.1.3.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.
  8. See Table R608.3 for thicknesses and dimensions of screen-grid walls.
  9. DR means design is required in accordance with the applicable building code, or in the absence of a code, in accordance with ACI 318.
  10. The use of this table shall be prohibited for soil classifications not shown.

TABLE R404.1.2(8)

MINIMUM VERTICAL REINFORCEMENT FOR 6-, 8-, 10- AND 12-INCH NOMINAL FLAT BASEMENT WALLSb, c, d, e, f, h, i, k, n, o

MAXIMUM WALL HEIGHT (feet) MAXIMUM UNBALANCED BACKFILL HEIGHTg (feet) MINIMUM VERTICAL REINFORCEMENT-BAR SIZE AND SPACING (inches)
Soil classesa and design lateral soil (psf per foot of depth)
GW, GP, SW, SP 30 GM, GC, SM, SM-SC and ML 45 SC, ML-CL and inorganic CL 60
Minimum nominal wall thickness (inches)
6 8 10 12 6 8 10 12 6 8 10 12
5 4 NR NR NR NR NR NR NR NR NR NR NR NR
5 NR NR NR NR NR NR NR NR NR NR NR NR
6 4 NR NR NR NR NR NR NR NR NR NR NR NR
5 NR NR NR NR NR NRl NR NR 4 @ 35 NRl NR NR
6 NR NR NR NR 5 @ 48 NR NR NR 5 @ 36 NR NR NR
7 4 NR NR NR NR NR NR NR NR NR NR NR NR
5 NR NR NR NR NR NR NR NR 5 @ 47 NR NR NR
6 NR NR NR NR 5 @ 42 NR NR NR 6 @ 43 5 @ 48 NRl NR
7 5 @ 46 NR NR NR 6 @ 42 5 @ 46 NRl NR 6 @ 34 6 @ 48 NR NR
8 4 NR NR NR NR NR NR NR NR NR NR NR NR
5 NR NR NR NR 4 @ 38 NRl NR NR 5 @ 43 NR NR NR
6 4 @ 37 NRl NR NR 5 @ 37 NR NR NR 6 @ 37 5 @ 43 NRl NR
7 5 @ 40 NR NR NR 6 @ 37 5 @ 41 NRl NR 6 @ 34 6 @ 43 NR NR
8 6 @ 43 5 @ 47 NRl NR 6 @ 34 6 @ 43 NR NR 6 @ 27 6 @ 32 6 @ 44 NR
9 4 NR NR NR NR NR NR NR NR NR NR NR NR
5 NR NR NR NR 4 @ 35 NRl NR NR 5 @ 40 NR NR NR
6 4 @ 34 NRl NR NR 6 @ 48 NR NR NR 6 @ 36 6 @ 39 NRl NR
7 5 @ 36 NR NR NR 6 @ 34 5 @ 37 NR NR 6 @ 33 6 @ 38 5 @ 37 NRl
8 6 @ 38 5 @ 41 NRl NR 6 @ 33 6 @ 38 5 @ 37 NRl 6 @ 24 6 @ 29 6 @ 39 4 @ 48m
9 6 @ 34 6 @ 46 NR NR 6 @ 26 6 @ 30 6 @ 41 NR 6 @ 19 6 @ 23 6 @ 30 6 @ 39
10 4 NR NR NR NR NR NR NR NR NR NR NR NR
5 NR NR NR NR 4 @ 33 NRl NR NR 5 @ 38 NR NR NR
6 5 @ 48 NRl NR NR 6 @ 45 NR NR NR 6 @ 34 5 @ 37 NR NR
7 6 @ 47 NR NR NR 6 @ 34 6 @ 48 NR NR 6 @ 30 6 @ 35 6 @ 48 NRl
8 6 @ 34 5 @ 38 NR NR 6 @ 30 6 @ 34 6 @ 47 NRl 6 @ 22 6 @ 26 6 @ 35 6 @ 45m
9 6 @ 34 6 @ 41 4 @ 48 NRl 6 @ 23 6 @ 27 6 @ 35 4 @ 48m DR 6 @ 22 6 @ 27 6 @ 34
10 6 @ 28 6 @ 33 6 @ 45 NR DRj 6 @ 23 6 @ 29 6 @ 38 DR 6 @ 22 6 @ 22 6 @ 28

For SI: 1 inch = 25.4 mm; 1 foot = 304.8 mm; 1 pound per square foot per foot = 0.1571 kPa2/m, 1 pound per square inch = 6.895 kPa.

NR = Not Required.

DR = Design Required.

  1. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
  2. Table values are based on reinforcing bars with a minimum yield strength of 60,000 psi.
  3. Vertical reinforcement with a yield strength of less than 60,000 psi and bars of a different size than specified in the table are permitted in accordance with Section R404.1.3.3.7.6 and Table R404.1.2(9).
  4. NR indicates vertical wall reinforcement is not required, except for 6-inch nominal walls formed with stay-in-place forming systems in which case vertical reinforcement shall be No. 4@48 inches on center.
  5. Allowable deflection criterion is L/240, where L is the unsupported height of the basement wall in inches.
  6. Interpolation is not permitted.
  7. Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
  8. Vertical reinforcement shall be located to provide a cover of 11/4 inches measured from the inside face of the wall. The center of the steel shall not vary from the specified location by more than the greater of 10 percent of the wall thickness or 3/8 inch.
  9. Concrete cover for reinforcement measured from the inside face of the wall shall be not less than 3/4 inch. Concrete cover for reinforcement measured from the outside face of the wall shall be not less than 11/2 inches for No. 5 bars and smaller, and not less than 2 inches for larger bars.
  10. DR means design is required in accordance with the applicable building code, or in the absence of a code, in accordance with ACI 318.
  11. Concrete shall have a specified compressive strength, f'c, of not less than 2,500 psi at 28 days, unless a higher strength is required by Footnote l or m.
  12. The minimum thickness is permitted to be reduced 2 inches, provided that the minimum specified compressive strength of concrete, f'c, is 4,000 psi.
  13. A plain concrete wall with a minimum nominal thickness of 12 inches is permitted, provided that the minimum specified compressive strength of concrete, f'c, is 3,500 psi.
  14. See Table R608.3 for tolerance from nominal thickness permitted for flat walls.
  15. The use of this table shall be prohibited for soil classifications not shown.

TABLE R404.1.2(9)

MINIMUM SPACING FOR ALTERNATE BAR SIZE AND ALTERNATE GRADE OF STEELa, b, c

BAR SPACING FROM APPLICABLE TABLE IN Section R404.1.3.2 (inches) BAR SIZE FROM APPLICABLE TABLE IN Section R404.1.3.2
#4 #5 #6
Alternate bar size and alternate grade of steel desired
Grade 60 Grade 40 Grade 60 Grade 40 Grade 60 Grade 40
#5 #6 #4 #5 #6 #4 #6 #4 #5 #6 #4 #5 #4 #5 #6
Maximum spacing for alternate bar size and alternate grade of steel (inches)
8 12 18 5 8 12 5 11 3 5 8 4 6 2 4 5
9 14 20 6 9 13 6 13 4 6 9 4 6 3 4 6
10 16 22 7 10 15 6 14 4 7 9 5 7 3 5 7
11 17 24 7 11 16 7 16 5 7 10 5 8 3 5 7
12 19 26 8 12 18 8 17 5 8 11 5 8 4 6 8
13 20 29 9 13 19 8 18 6 9 12 6 9 4 6 9
14 22 31 9 14 21 9 20 6 9 13 6 10 4 7 9
15 23 33 10 16 22 10 21 6 10 14 7 11 5 7 10
16 25 35 11 17 23 10 23 7 11 15 7 11 5 8 11
17 26 37 11 18 25 11 24 7 11 16 8 12 5 8 11
18