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
TABLE R404.1.1(2) 8-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d ≥ 5 INCHESa, c, f
TABLE R404.1.1(3) 10-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d ≥ 6.75 INCHESa, c, f
TABLE R404.1.1(4) 12-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d ≥ 8.75 INCHESa, c, f
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. |
| a. 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. |
| b. Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1. |
| c. 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. |
| d. Solid indicates solid masonry unit; grout indicates grouted hollow units. |
| e. 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. |
| f. 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. |
| a. Mortar shall be Type M or S and masonry shall be laid in running bond. |
| b. 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. |
| c. 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. |
| d. 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. |
| e. 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. |
| f. 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. |
| a. Mortar shall be Type M or S and masonry shall be laid in running bond. |
| b. 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. |
| c. 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. |
| d. 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. |
| e. 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. |
| f. 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) 5 feet 6 feet 8 inches | #4 at 72 #4 at 72 #4 at 72 | #4 at 72 #4 at 72 #4 at 72 | #4 at 72 #4 at 72 #5 at 72 |
| 7 feet 4 inches | 4 feet (or less) 5 feet 6 feet 7 feet 4 inches | #4 at 72 #4 at 72 #4 at 72 #4 at 72 | #4 at 72 #4 at 72 #4 at 72 #5 at 72 | #4 at 72 #4 at 72 #5 at 72 #6 at 72 |
| 8 feet | 4 feet (or less) 5 feet 6 feet 7 feet 8 feet | #4 at 72 #4 at 72 #4 at 72 #4 at 72 #5 at 72 | #4 at 72 #4 at 72 #4 at 72 #5 at 72 #6 at 72 | #4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 64 |
| 8 feet 8 inches | 4 feet (or less) 5 feet 6 feet 7 feet 8 feet 8 inches | #4 at 72 #4 at 72 #4 at 72 #4 at 72 #5 at 72 | #4 at 72 #4 at 72 #4 at 72 #5 at 72 #7 at 72 | #4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 48 |
| 9 feet 4 inches | 4 feet (or less) 5 feet 6 feet 7 feet 8 feet 9 feet 4 inches | #4 at 72 #4 at 72 #4 at 72 #4 at 72 #5 at 72 #6 at 72 | #4 at 72 #4 at 72 #5 at 72 #5 at 72 #6 at 72 #6 at 48 | #4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 56 #6 at 40 |
| 10 feet | 4 feet (or less) 5 feet 6 feet 7 feet 8 feet 9 feet 10 feet | #4 at 72 #4 at 72 #4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 64 | #4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 72 #6 at 56 #6 at 40 | #4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 48 #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. |
| a. Mortar shall be Type M or S and masonry shall be laid in running bond. |
| b. 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. |
| c. 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. |
| d. 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. |
| e. 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. |
| f. The use of this table shall be prohibited for soil classifications not shown. |