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:
In buildings that have no more than two floors and a
roof.
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. Gravel fill used as footings for
wood and precast concrete foundations shall comply with
Section R403.
Surface drainage shall be diverted to a
storm sewer conveyance or other approvedpoint of collection
that does not create a hazard. 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 2 percent away from the building.
Where quantifiable data created by
accepted soil science methodologies indicate expansive, compressible,
shifting 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 approvedmethod.
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.
Where soil tests are required by Section R401.4, the allowable bearing capacities of the soil shall be part of the recommendations.
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.
Fasteners used below gradeto attach
plywood to the exterior side of exterior basementor crawlspace
wall studs, or fasteners used in knee wall construction,
shall be of Type 304 or 316 stainless steel. Fasteners
used above gradeto 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.
All lumber and plywood shall
be pressure-preservative treated and dried after treatment
in accordance with A WPA U1 (Commodity Specification
A, Use Category 4B and Section 5.2), and shall bear the
label of an accredited agency. Where lumber and/or plywood
is cut or drilled after treatment, the treated surface
shall be field treated with copper naphthenate, the concentration of which shall contain a minimum of 2-percent
copper metal, by repeated brushing, dipping or soaking
until the wood absorbs no more preservative.
Concrete shall have a minimum specified
compressive strength of ƒ' 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.
Concrete in these locations that is subject to freezing and thawing during construction shall be air-entrained concrete in accordance with Footnoted.
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.
See Section R402.2 for maximum cementitious materials content.
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.
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.
All concrete used in the manufacture of precast concrete
foundations shall have a minimum compressive
strength of 5,000 psi (34470 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.
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).
Panel-to-panel connections shall be made with
Grade II steel fasteners.
The use of nonstructural fibers shall conform to
ASTM C1116.
Grout used for bedding precast foundations placed
upon 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).
All exterior walls shall be supported on continuous solid or fully grouted masonry or concrete footings, crushed stone footings, wood foundations, or other approvedstructural systems which 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.
For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
Interpolation allowed. Extrapolation is not allowed.
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
For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
Interpolation allowed. Extrapolation is not allowed.
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 I inch of footing thickness (but not less than 6 inches thick).
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
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
For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.
Interpolation allowed. Extrapolation is not allowed.
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, 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).
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.
All required interior braced wall panels in buildings located
in Seismic Design Categories D0, D1 and D2 with plan
dimensions greater than 50 feet (15240 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 (15240 mm) provided that:
The height of cripple walls does not exceed 4 feet
(1219 mm).
First-floor braced wall panels are supported on
doubled floor joists, continuous blocking or floor
beams.
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:
In Seismic Design Categories D0, D1 and D2 where
a construction joint is created between a concrete footing
and a concrete stem wall, a minimum of 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 a minimum of 14 inches (357
mm) into the stem wall. Standard hooks shall comply
with Section R608.5.4.5. A minimum of 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, a minimum of 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 a minimum of 14 inches (357 mm) into the stem wall.
Standard hooks shall comply with Section R608.5.4.5.
A minimum of 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 a minimum of 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.
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.
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.
All exterior footings and foundation systems shall extend 42 inches below actual grade. Where applicable, the depth of the footings shall also conform to Section R403.1.4.1 of the code.
Exception: Upon evidence of the existence of any of the following conditions, the building official may modify the footing depth accordingly:
Freezing temperatures (freezing degree days).
Soil type.
Ground water conditions.
Snow depth experience.
Exposure to the elements.
Other specific conditions identified by the building official that may affect the foundation system.
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:
Extended below the frost line specified in Table
R301.2.(1).
Protection of freestanding 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.
Protection of freestanding 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.
Decks not supported by a dwelling need not be
provided with footings that extend below the
frost line.
Footings shall not bear on frozen soil unless the frozen
condition is permanent.
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 anchored to
the foundation. Anchorage of cold-formed steel framing
and sill plates supporting cold-formed steel framing shall
be in accordance with this section and Section R505.3.1 or
R603.3.1.
Wood sole plates at all exterior walls on monolithic
slabs, wood sole plates of braced wall panels at building
interiors on monolithic slabs and all wood sill plates shall
be anchored to the foundation with minimum 1/2-inchdiameter
(12.7 mm) anchor bolts spaced a maximum of 6
feet (1829 mm) on center or approved anchors or anchor
straps spaced as required to provide equivalent anchorage
to 1/2-inch-diameter (12.7 mm) anchor bolts. Bolts shall
extend a minimum of 7 inches (178 mm) into concrete or
grouted cells of concretemasonry units. The bolts shall be
located in the middle third of the width of the plate. A nut
and washer shall be tightened on each anchor bolt. There
shall be a minimum of two bolts per plate section with one
bolt located not more than 12 inches (305 mm) or less than
seven bolt diameters from each end of the plate section.
Interior bearing wall sole plates on monolithic slab foundation
that are not part of a braced wall panel shall be positively
anchored with approvedfasteners. Sill plates and
sole plates shall be protected against decay and termites
where required by Sections R317 and R318.
Exceptions:
Walls 24 inches (610 mm) total length or shorter
connecting offsetbraced wall panels shall be
anchored to the foundation with a minimum of
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).
Connection of walls 12 inches (305 mm) total
length or shorter connecting offsetbraced 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).
Plate washers conforming to Section R602.11.1
shall be provided for all anchor bolts over the full
length of required braced wall linesexcept where
approvedanchor straps are used. Properly sized
cut washers shall be permitted for anchor bolts in
wall lines not containing braced wall panels.
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 when supported on a
continuous foundation.
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 when supported
on a continuous foundation.
The maximum anchor bolt spacing shall be 4 feet
(1219 mm) for buildings over two stories in
height.
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.
For SI: 1 foot = 304.8 mm.
FIGURE R403.1.7.1
FOUNDATION CLEARANCE FROM SLOPES
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 approveddrainage device a minimum of 12
inches (305 mm) plus 2 percent. Alternate elevations
are permitted subject to the approval of the building
official, provided 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
which 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 four of the following provisions shall be considered 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:
Plasticity Index (PI) of 15 or greater, determined in accordance with ASTM D4318.
More than 10 percent of the soil particles pass a No. 200 sieve (75 μm), determined in accordance with ASTM D422.
More than 10 percent of the soil particles are less than 5 micrometers in size, determined in accordance with ASTM D422.
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 a minimum of 64°F (18°C), footings are not required to extend below the frost line when 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 gradefor the purpose of insulating footings against frost shall be labeledas complying with ASTMC578. For SI: 1 inch= 25.4 mm.
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
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-VEAR RETURN PERIOD
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-VALUE c, d
HORIZONTAL INSULATION R-VALUEc, e
HORIZONTAL INSULATION DIMENSIONS PER FIGURE R403.3(1) (inches)
Insulation requirements are for protection against frost damage in heated buildings. Greater values may be required to meet energy conservation standards.
See Figure R403.3(2) or Table R403.3(2) for Air Freezing Index values.
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-2.4R per inch; Type IV extruded polystyrene -4.5R per inch; Type VI extruded polystyrene -4.5R per inch; Type IX expanded polystyrene-3.2R per inch; Type X extruded polystyrene-4.5R per inch.
Vertical insulation shall be expanded polystyrene insulation or extruded polystyrene insulation
Horizontal insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.
TABLE R403.3(2) AIR-FREEZING INDEX FOR MICHIGAN LOCATIONS BY COUNTY
AIR-FREEZING INDEX
1500 or
2000
2500
3000
3500
4000
Berrien Branch Cass Kalamazoo Macomb Ottawa St. Clair St. Joseph
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 a minimum of 64°F
(l8°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.
For SI: 1 inch = 25.4 mm.
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
Where a
frost-protected shallow foundation abuts a structure
that has a monthly mean temperature maintained at a
minimum of 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.
FIGURE R403.3(4)
INSULATION PLACEMENT FOR FROST-PROTECTED FOOTINGS ADJACENT TO HEATED STRUCTURE
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 approvedmaterials placed below ground, directly
above the top surface of the insulation.
Final gradeshall 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 approvedsewer system.
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 than1/16 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 a maximum of 8-inch (203 mm)
lifts. Crushed stone footings shall be limited to Seismic
Design Categories A, B and C.
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:
Walls are subject to hydrostatic pressure from ground water.
Walls supporting more than 48 inches (1219 mm) of unbalanced backfill that do not have permanent lateral support at the top or bottom.
6 groutd or 8 solidd or 12 6 groutd or 10 solidd 8 groutd or 12 solidd 10 groutd 10 groutd 12 grout
6 groutd or 8 solidd 8 groutd or 12 solidd 10 groutd 10 groutd 12 grout Footnote e
8 groutd or 10solidd 8 groutd 10 groutd 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.
Mortar shall be Type M or S and masonry shall be laid in running bond. Ungrouted hollowmasonry units are permitted except where otherwise indicated.
Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
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 at 48 #4 at 48 #4 at 48 #5 at 48 #6 at 48 #6 at 40 #6 at 32
#4 at 48 #4 at 48 #5 at 48 #6 at 48 #6 at 32 #6 at 24 #6 at 16
#4 at 48 #5 at 48 #6 at 48 #6 at 32 #6 at 24 #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.
Mortar shall be Type M or S and masonry shall be laid in running bond.
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.
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.
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.
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.
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 INCHES a, 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)
#4 at 56 #4 at 56 #4 at 56 #5 at 56 #5 at 56 #6 at 56 #6 at 48
#4 at 56 #4 at 56 #5 at 56 #6 at 56 #6 at 48 #6 at 40 #6 at 32
#4 at 56 #4 at 56 #5 at 56 #6 at 48 #6 at 40 #6 at 24 #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.
Mortar shall be Type M or S and masonry shall be laid in running bond.
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.
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.
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.
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.
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 INCHES a, 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)
#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.
Mortar shall be Type M or S and masonry shall be laid in running bond.
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.
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.
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.
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.
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/ACI 530/ASCE 5. When TMS 402/ACI 530/ASCE 5 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.
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.
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.
See Section R404.1.2.2 for minimum reinforcement required for foundation walls supporting above-gradeconcretewalls.
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.
Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
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.
Vertical reinforcement with a yield strength of less than 60,000 psi and/or 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).
Deflection criterion is L/240, where L is the height of the basement wall in inches.
Interpolation is not permitted.
Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
NR indicates no vertical wall reinforcement is 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.
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.
Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
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.
Vertical reinforcement with a yield strength of less than 60,000 psi and/or 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).
NR indicates no vertical reinforcement is required.
Deflection criterion is L/240, where L is the height of the basement wall in inches.
Interpolation is not permitted.
Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
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.
Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
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.
Vertical reinforcement with a yield strength of less than 60,000 psi and/or 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).
NR indicates no vertical reinforcement is required.
Deflection criterion is L/240, where L is the height of the basement wall in inches.
Interpolation is not permitted.
Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
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.
Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
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.
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 (i.e., 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/or 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).
Deflection criterion is L/240, where L is the height of the basement wall in inches.
Interpolation is not permitted.
Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
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.
Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
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.
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 (i.e., 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/or 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).
NR indicates no vertical reinforcement is required.
Deflection criterion is L/240, where L is the height of the basement wall in inches.
Interpolation shall not be permitted.
Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
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.
Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
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.
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 (i.e., 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/or 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).
Deflection criterion is L/240, where L is the height of the basement wall in inches.
Interpolation is not permitted.
Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
See Table R608.3 for thicknesses and dimensions of screen-grid walls.
DR means design is required in accordance with the applicable building code, or where there is no code, in accordance with ACI 318.
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 BASEMENTWALLSb, 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
NR1
NR
NR
4 @ 35
NR1
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
NR1
NR
7
5 @ 46
NR
NR
NR
6 @ 42
5 @ 46
NR1
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
NR1
NR
NR
5 @ 43
NR
NR
NR
6
4 @ 37
NR1
NR
NR
5 @ 37
NR
NR
NR
6 @ 37
5 @ 43
NR1
NR
7
5 @ 40
NR
NR
NR
6 @ 37
5 @ 41
NR1
NR
6 @ 34
6 @ 43
NR
NR
8
6 @ 43
5 @ 47
NR1
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
NR1
NR
NR
5 @ 40
NR
NR
NR
6
4 @ 34
NR1
NR
NR
6 @ 48
NR
NR
NR
6 @ 36
6 @ 39
NR1
NR
7
5 @ 36
NR
NR
NR
6 @ 34
5 @ 37
NR
NR
6 @ 33
6 @ 38
5 @ 37
NR1
8
6 @ 38
5 @41
NR1
NR
6 @ 33
6 @ 38
5 @ 37
NR1
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
NR1
NR
NR
5 @ 38
NR
NR
NR
6
5 @ 48
NR1
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
NR1
8
6 @ 34
5 @ 38
NR
NR
6 @ 30
6 @ 34
6 @ 47
NR1
6 @ 22
6 @ 26
6 @ 35
6 @ 45m
9
6 @ 34
6 @ 41
4 @ 48
NR1
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.
Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.
Table values are based on reinforcing bars with a minimum yield strength of 60,000 psi.
Vertical reinforcement with a yield strength of less than 60,000 psi and/or 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).
NR indicates no vertical wall reinforcement is 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.
Allowable deflection criterion is L/240, where L is the unsupported height of the basement wall in inches.
Interpolation is not permitted.
Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.
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.
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.
DR means design is required in accordance with the applicable building code, or where there is no code, in accordance with ACI 318.
Concrete shall have a specified compressive strength,ƒ'c of not less than 2,500 psi at 28 days, unless a higher strength is required by Footnote l or m.
The minimum thickness is permitted to be reduced 2 inches, provided the minimum specified compressive strength of concrete,ƒ'c is 4,000 psi.
A plain concrete wall with a minimum nominal thickness of 12 inches is permitted, provided minimum specified compressive strength of concrete,ƒ'c is 3,500 psi.
See Table R608.3 for tolerance from nominal thickness permitted for flat walls.
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/OR ALTERNATE GRADE OF STEEL a, b, c
Maximum spacing for alternate bar size and/or 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
28
40
12
19
26
12
26
8
12
17
8
13
5
8
12
19
29
42
13
20
28
12
27
8
13
18
9
13
6
9
13
20
31
44
13
21
29
13
28
9
13
19
9
14
6
9
13
21
33
46
14
22
31
14
30
9
14
20
10
15
6
10
14
22
34
48
15
23
32
14
31
9
15
21
10
16
7
10
15
23
36
48
15
24
34
15
33
10
15
22
10
16
7
11
15
24
37
48
16
25
35
15
34
10
16
23
11
17
7
11
16
25
39
48
17
26
37
16
35
11
17
24
11
18
8
12
17
26
40
48
17
27
38
17
37
11
17
25
12
18
8
12
17
27
42
48
18
28
40
17
38
12
18
26
12
19
8
13
18
28
43
48
19
29
41
18
40
12
19
26
13
20
8
13
19
29
45
48
19
30
43
19
41
12
19
27
13
20
9
14
19
30
47
48
20
31
44
19
43
13
20
28
14
21
9
14
20
31
48
48
21
32
45
20
44
13
21
29
14
22
9
15
21
32
48
48
21
33
47
21
45
14
21
30
15
23
10
15
21
33
48
48
22
34
48
21
47
14
22
31
15
23
10
16
22
34
48
48
23
35
48
22
48
15
23
32
15
24
10
16
23
35
48
48
23
36
48
23
48
15
23
33
16
25
11
16
23
36
48
48
24
37
48
23
48
15
24
34
16
25
11
17
24
37
48
48
25
38
48
24
48
16
25
35
17
26
11
17
25
38
48
48
25
39
48
25
48
16
25
36
17
27
12
18
25
39
48
48
26
40
48
25
48
17
26
37
18
27
12
18
26
40
48
48
27
41
48
26
48
17
27
38
18
28
12
19
27
41
48
48
27
42
48
26
48
18
27
39
19
29
12
19
27
42
48
48
28
43
48
27
48
18
28
40
19
30
13
20
28
43
48
48
29
44
48
28
48
18
29
41
20
30
13
20
29
44
48
48
29
45
48
28
48
19
29
42
20
31
13
21
29
45
48
48
30
47
48
29
48
19
30
43
20
32
14
21
30
46
48
48
31
48
48
30
48
20
31
44
21
32
14
22
31
47
48
48
31
48
48
30
48
20
31
44
21
33
14
22
31
48
48
48
32
48
48
31
48
21
32
45
22
34
15
23
32
For SI: 1 inch = 25.4 mm, 1 pound per square inch = 6.895 kPa.
This table is for use with tables in Section R404.1.3.2 that specify the minimum bar size and maximum spacing of vertical wall reinforcement for foundation walls and above-gradewalls. Reinforcement specified in tables in Section R404.1.3.2 is based on Grade 60 steel reinforcement.
Bar spacing shall not exceed 48 inches on center and shall be not less than one-half the nominal wall thickness.
For Grade 50 steel bars (ASTM A996, Type R), use spacing for Grade 40 bars or interpolate between Grades 40 and 60.
Concrete foundation
walls that support light-frame walls shall be designed
and constructed in accordance with the provisions of this
section, ACI 318, ACI 332 or PCA 100. Concrete foundation
walls that support above-gradeconcretewalls that are
within the applicability limits of Section R608.2 shall be
designed and constructed in accordance with the provisions
of this section, ACI 318, ACI 332 or PCA 100. Concrete
foundation walls that support above-gradeconcretewalls that are not within the applicability limits of Section
R608.2 shall be designed and constructed in accordance
with the provisions of ACI 318, ACI 332 or PCA 100.
When ACI 318, ACI 332, PCA 100 or the provisions of
this section are used to design concrete 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 jurisdictionhaving authority.
Concretewalls
constructed in accordance with this code shall comply
with the shapes and minimum concrete cross-sectional
dimensions required by Table R608.3. Other types of
forming systems resulting in concretewalls not in compliance
with this section and Table R608.3 shall be
designed in accordance with ACI 318.
Foundation
stem walls that support above-gradeconcretewalls shall be designed and constructed in accordance
with this section.
Stem walls not laterally supported at top. Concrete
stem walls that are not monolithic with
slabs-on-ground or are not otherwise laterally
supported by slabs-on-ground shall comply
with this section. Where unbalanced backfill
retained by the stem wall is less than or equal to
18 inches (457 mm), the stem wall and above-grade
wall it supports shall be provided with
vertical reinforcement in accordance with Section
R608.6 and Table R608.6(1), R608.6(2) or
R608.6(3) for above-gradewalls. Where unbalanced
backfill retained by the stem wall is
greater than 18 inches (457 mm), the stem wall
and above-grade wall it supports shall be provided
with vertical reinforcement in accordance
with Section R608.6 and Table R608.6(4).
Stem walls laterally supported at top. Concrete
stem walls that are monolithic with slabs-on-ground
or are otherwise laterally supported by
slabs-on-ground shall be vertically reinforced
in accordance with Section R608.6 and Table
R608.6(1), R608.6(2) or R608.6(3) for above-gradewalls. Where the unbalanced backfill
retained by the stem wall is greater than 18
inches (457 mm), the connection between the
stem wall and the slab-on-ground, and the portion
of the slab-on-ground providing lateral
support for the wall shall be designed in accordance
with PCA 100 or with accepted engineering
practice. Where the unbalanced backfill
retained by the stem wall is greater than 18
inches (457 mm), the minimum nominal thickness
of the wall shall be 6 inches (152 mm).
Concrete foundation stem walls that support light-frame above-gradewalls shall be designed and constructed in accordance with this section.
Stem walls not laterally supported at top. Concrete stem walls that are not monolithic with slabs-on-ground or are not otherwise laterally supported by slabs-on-ground and retain 48 inches (1219 mm) or less of unbalanced fill, measured from the top of the wall, shall be constructed in accordance with Section R404.1.3. Foundation stem walls that retain more than 48 inches (1219 mm) of unbalanced fill, measured from the top of the wall, shall be designed in accordance with Sections R404.1.4 and R404.4.
Stem walls laterally supported at top. Concrete stem walls that are monolithic with slabs-on-ground or are otherwise laterally supported by slabs-on-ground shall be constructed in accordance with Section R404.1.3. Where the unbalanced backfill retained by the stem wall is greater than 48 inches (1219 mm), the connection between the stem wall and the slab-on-ground, and the portion of the slab-on-ground providing lateral support for the wall, shall be designed in accordance with PCA 100 or in accordance with accepted engineering practice.
The minimum specified compressive strength of concrete,ƒ'c, shall comply with Section R402.2 and shall be not less than 2,500 psi (17.2 MPa) at 28 days in buildings assigned to Seismic Design Category A, B or C and 3000 psi (20.5 MPa) in buildings assigned to Seismic Design Category D0, D1 or D2.
The nominal
maximum size of coarse aggregate shall not
exceed one-fifth the narrowest distance between
sides of forms, or three-fourths the clear spacing
between reinforcing bars or between a bar and the
side of the form.
Exception: When approved, these limitations
shall not apply where removable forms are used
and workability and methods of consolidation
permitconcrete to be placed without honeycombs
or voids.
Proportions of materials for concrete shall be established to provide workability and consistency to permitconcrete to be worked readily into forms and
around reinforcement under conditions of placement
to be employed, without segregation or excessive
bleeding. Slump of concrete placed in removable
forms shall not exceed 6 inches (152 mm).
Exception: When approved, the slump is permitted
to exceed 6 inches (152 mm) for concrete
mixtures that are resistant to segregation, and are
in accordance with the form manufacturer's recommendations.
Slump of concrete placed in stay-in-place forms
shall exceed 6 inches (152 mm). Slump of concrete
shall be determined in accordance with ASTM
C143.
Concrete
shall be consolidated by suitable means during
placement and shall be worked around embedded
items and reinforcement and into corners of forms.
Where stay-in-place forms are used, concrete shall
be consolidated by internal vibration.
Exception: When approvedfor concrete to be
placed in stay-in-place forms, self-consolidating
concrete mixtures with slumps equal to or greater
than 8 inches (203 mm) that are specifically
designed for placement without internal vibration
need not be internally vibrated.
Forms shall be made of wood, steel, aluminum, plastic, a
composite of cement and foam insulation, a composite
of cement and wood chips, or other approved
material suitable for supporting and containing concrete.
Forms shall provide sufficient strength to contain
concrete during the concrete placement
operation.
Form ties shall be steel, solid plastic, foam plastic,
a composite of cement and wood chips, a composite
of cement and foam plastic, or other suitable
material capable of resisting the forces created by
fluid pressure of fresh concrete.
Stay-in-place
concrete forms shall comply with this section.
Surface burning characteristics. The flame-spread
index and smoke-developed index
of forming material, other than foam plastic,
left exposed on the interior shall comply
with Section R302. The surface burning
characteristics of foam plastic used in insulating
concrete forms shall comply with
Section R316.3.
Interior covering. Stay-in-place forms constructed
of rigid foam plastic shall be protected
on the interior of the building as
required by Section R316. Where gypsum
board is used to protect the foam plastic, it shall be installed with a mechanical fastening
system. Use of adhesives in addition to
mechanical fasteners is permitted.
Exterior wall covering. Stay-in-place forms
constructed of rigid foam plastics shall be
protected from sunlight and physical damage
by the application of an approved exterior
wall covering complying with this
code. Exterior surfaces of other stay-in-place
forming systems shall be protected in
accordance with this code.
Termite protection. In areas where the probability
of termite infestation is "very heavy"
as indicated by Table R301.2(1) or Figure
R301.2(6), foam plastic insulation shall be permitted below grade on foundation walls
in accordance with Section R318.4.
Flat ICF wall system forms shall conform
to ASTM E2634.
Steel reinforcement
shall comply with the requirements of
ASTM A615, A706, or A996. ASTM A996 bars
produced from rail steel shall be Type R. In
buildings assigned to Seismic Design Category
A, B or C, the minimum yield strength of reinforcing
steel shall be 40,000 psi (Grade 40) (276
MPa). In buildings assigned to Seismic Design
Category D0, D1 or D2, reinforcing steel shall comply with the requirements of ASTM A706 for
low-alloy steel with a minimum yield strength of
60,000 psi (Grade 60) (414 MPa).
The center of vertical reinforcement in
basementwalls determined from Tables
R404.1.2(2) through R404.1.2(7) shall be located
at the centerline of the wall. Vertical reinforcement
in basementwalls determined from Table
R404.1.2(8) shall be located to provide a maximum
cover of 11/4 inches (32 mm) measured
from the inside face of the wall. Regardless of the
table used to determine vertical wall reinforcement,
the center of the steel shall not vary from
the specified location by more than the greater of 10 percent of the wall thickness and 3/8 inch (10
mm). Horizontal and vertical reinforcement shall
be located in foundation walls to provide the minimum
cover required by Section R404.1.3.3.7.4.
Vertical wall
reinforcement required by Section R404.1.3.2
that is interrupted by wall openings shall have
additional vertical reinforcement of the same size
placed within 12 inches (305 mm) of each side of
the opening.
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). The minus tolerance for
cover shall not exceed the smaller of one-third the
required cover or 3/8 inch (10 mm).
Vertical and horizontal
wall 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)].
Where tables in Section
R404.1.3.2 specify vertical wall reinforcement
based on minimum bar size and maximum spacing,
which are based on Grade 60 (414 MPa)
steel reinforcement, different size bars or bars
made from a different grade of steel are permitted
provided an equivalent area of steel per linear
foot of wall is provided. Use of Table
R404.1.2(9) is permitted to determine the maximum
bar spacing for different bar sizes than
specified in the tables or bars made from a different
grade of steel. Bars shall not be spaced less
than one-half the wall thickness, or more than 48
inches (1219 mm) on center.
Construction joints in foundation walls
shall be made and located to not impair the
strength of the wall. Construction joints in plain
concretewalls, including walls required to have
not less than No. 4 bars at 48 inches (1219 mm) on
center by Sections R404.1.3.2 and R404.1.4.2,
shall be located at points of lateral support, and a
minimum of one No. 4 bar shall extend across the
construction joint at a spacing not to exceed 24
inches (610 mm) on center. Construction joint
reinforcement shall have a minimum of 12 inches
(305 mm) embedment on both sides of the joint.
Construction joints in reinforced concretewalls
shall be located in the middle third of the span
between lateral supports, or located and constructed
as required for joints in plain concretewalls.
Exception: Use of vertical wall reinforcement
required by this code is permitted in lieu of
construction joint reinforcement provided the
spacing does not exceed 24 inches (610 mm),
or the combination of wall reinforcement and
No.4 bars described above does not exceed 24
inches (610 mm).
Requirements
for installation of masonry veneer, stucco and
other wall coverings on the exterior of concretewalls
and other construction details not covered in this section
shall comply with the requirements of this code.
In buildings
assigned to Seismic Design Category D0, D1 or D2, as
established in Table R301.2(1), masonry foundation walls shall comply with this section. In addition to the
requirements of Table R404.1.1(1), plain masonry
foundation walls shall comply with the following:
Wall height shall not exceed 8 feet (2438 mm).
Unbalanced backfill height shall not exceed 4
feet (1219 mm).
Minimum nominal thickness for plain masonry
foundation walls shall be 8 inches (203 mm).
Masonry stem walls shall have a minimum vertical
reinforcement of one No. 4 (No. 13) bar
located a maximum of 4 feet (1219 mm) on center
in grouted cells. Vertical reinforcement shall be
tied to the horizontal reinforcement in the footings.
Foundation walls, supporting more than 4 feet (1219
mm) of unbalanced backfill or exceeding 8 feet (2438
mm) in height shall be constructed in accordance with
Table R404.1.1(2), R404.1.1(3) or R404.1.1(4).
Masonry foundation walls shall have two No. 4 (No. 13)
horizontal bars located in the upper 12 inches (305 mm)
of the wall.
Unbalanced backfill height shall not exceed 4
feet (1219 mm).
Minimum thickness for plain concrete foundation
walls shall be 7.5 inches (191 mm) except that 6
inches (152 mm) is permitted where the maximum
wall height is 4 feet, 6 inches (1372 mm).
Foundation walls less than 7.5 inches (191 mm) in
thickness, supporting more than 4 feet (1219 mm) of
unbalanced backfill or exceeding 8 feet (2438 mm) in
height shall be provided with horizontal reinforcement
in accordance with Table R404.1.2(1), and vertical
reinforcement in accordance with Table R404.1.2(2),
R404.1.2(3), R404.1.2(4), R404.1.2(5), R404.1.2(6),
R404.1.2(7) or R404.1.2(8). Where Tables R404.1.2(2)
through R404.1.2(8) permit plain concretewalls, not
less than No. 4 (No. 13) vertical bars at a spacing not
exceeding 48 inches (1219 mm) shall be provided.
The thickness of masonry or concrete foundation
walls shall be not less than that required by Section
R404.1.5.1 or R404.1.5.2, respectively.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 degree = 0.0175 rad FIGURE R404.1.5(1)
FOUNDATION WALL CLAY MASONRY CURTAIN WALL WITH CONCRETE MASONRY PIERS
Masonry foundation
walls shall be not bless than the thickness of the
wall supported, except that masonry foundation walls of at least 8-inch (203 mm) nominal thickness shall be
permitted under brick veneered frame walls and under
10-inch-wide (254 mm) cavity walls where the total
height of the wall supported, including gables, is not
more than 20 feet (6096 mm), provided the requirements
of Section R404.1.1 are met.
The thickness of
concrete foundation walls shall be equal to or greater
than the thickness of the wall in the storyabove. Concrete
foundation walls with corbels, brackets or other
projections built into the wall for support of masonry
veneer or other purposes are not within the scope of the
tables in this section.
Where a concrete foundation wall is reduced in
thickness to provide a shelf for the support of masonry
veneer, the reduced thickness shall be equal to or
greater than the thickness of the wall in the storyabove.
Vertical reinforcement for the foundation wall shall be
based on Table R404.1.2(8) and located in the wall as
required by Section R404.1.3.3.7.2 where that table is
used. Vertical reinforcement shall be based on the
thickness of the thinner portion of the wall.
Exception: Where the height of the reduced thickness
portion measured to the underside of the floor
assembly or sill plate above is less than or equal to
24 inches (610 mm) and the reduction in thickness
does not exceed 4 inches (102 mm), the vertical
reinforcement is permitted to be based on the thicker
portion of the wall.
Use of
pier and curtain wall foundations shall be permitted to
support light-frame construction not more than two stories
in height, provided the following requirements are
met:
The minimum actual thickness of a load-bearing
masonry wall shall be not less than 4 inches (102
mm) nominal or 33/8 inches (92 mm) actual thickness,
and shall be bonded integrally with piers
spaced in accordance with Section R606.6.4.
Piers shall be constructed in accordance with Sections
R606.7 and R606.7.1, and shall be bonded
into the load-bearing masonry wall in accordance
with Section R606.13.1 or R606.13.1.1.
The maximum height of a 4-inch (102 mm) loadbearing
masonry foundation wall supporting
wood-frame walls and floors shall be not more
than 4 feet (1219 mm).
Anchorage shall be in accordance with Section
R403.1.6, Figure R404.1.5(1), or as specified by engineered design accepted by the building official.
The unbalanced fill for 4-inch (102 mm) foundation
walls shall not exceed 24 inches (610 mm)
for solid masonry or 12 inches (305 mm) for hollow
masonry.
In Seismic Design Categories D0, D1, and D2, prescriptive
reinforcement shall be provided in the
horizontal and vertical direction. Provide minimum
horizontal joint reinforcement of two No. 9
gage wires spaced not less than 6 inches (152 mm)
or one 1/4-inch-diameter (6.4 mm) wire at 10
inches (254 mm) on center vertically. Provide
minimum vertical reinforcement of one No. 4 bar
at 48 inches (1220 mm) on center horizontally
grouted in place.
Concrete and
masonry foundation walls shall extend above the finished
gradeadjacent to the foundation at all points a minimum
of 4 inches (102 mm) where masonry veneer is used and a
minimum of 6 inches (152 mm) elsewhere.
Backfill shall not be placed
against the wall until the wall has sufficient strength and
has been anchored to the floor above, or has been sufficiently
braced to prevent damage by the backfill.
Exception: Bracing is not required for walls supporting
less than 4 feet (1219 mm) of unbalanced backfill.
Rubble stone masonry
foundation walls shall have a minimum thickness of 16
inches (406 mm), shall not support an unbalanced backfill
exceeding 8 feet (2438 mm) in height, shall not support a
soil pressure greater than 30 pounds per square foot per
foot (4.71 kPa/m), and shall not be constructed in Seismic
Design Categories D0, D1, D2 or townhouses in Seismic
Design Category C, as established in Figure R301.2(2).
Isolated masonry piers
shall be constructed in accordance with this section and
the general masonry construction requirements of Section
R606. Hollow masonry piers shall have a minimum nominal
thickness of 8 inches (203 mm), with a nominal height
not exceeding four times the nominal thickness and a nominal
length not exceeding three times the nominal thickness.
Where hollowmasonry units are solidly filled with
concrete or grout, piers shall be permitted to have a nominal
height not exceeding ten times the nominal thickness.
Footings for isolated masonry piers shall be sized in accordance
with Section R403.1.1.
Hollow masonry piers shall be
capped with 4 inches (102 mm) of solid masonry or
concrete, a masonry cap block, or shall have cavities of
the top course filled with concrete or grout. Where
required, termite protection for the pier cap shall be
provided in accordance with Section R318.
Masonry piers supporting wood girders sized in accordance
with Tables R602.7(1) and R602.7(2) shall be
permitted in accordance with this section. Piers supporting
girders for interior bearing walls shall have a
minimum nominal dimension of 12 inches (305 mm)
and a maximum height of 10 feet (3048 mm) from top
of footing to bottom of sill plate or girder. Piers supporting
girders for exterior bearing walls shall have a
minimum nominal dimension of 12 inches (305 mm)
and a maximum height of 4 feet (1220 mm) from top of
footing to bottom of sill plate or girder. Girders and sill
plates shall be anchored to the pier or footing in accordance
with Section R403.1.6 or Figure R404.1.5(1).
Floor girder bearing shall be in accordance with Section
R502.6.
Masonry piers in dwellingslocated in Seismic Design
Category D0, D1 or D2, and townhouses in Seismic
Design Category C, shall be designed in accordance
with accepted engineering practice.
Load-bearing lumber shall be
identified by the grademark of a lumber grading or
inspection agency which has been approvedby an accreditation
body that complies with DOC PS 20. In lieu of a
grademark, a certificate of inspection issued by a lumber
grading or inspection agency meeting the requirements of
this section shall be accepted. Wood structural panels shall
conform to DOC PS 1 or DOC PS 2 and shall be identified
by a grademark or certificate of inspection issued by an
approved agency.
The studs used in foundation walls
shall be 2-inch by 6-inch (51 mm by 152 mm) members.
When spaced 16 inches (406 mm) on center, a wood species
with an Fbvalue of not less than 1,250 pounds per
square inch (8619 kPa) as listed in ANSI AWC NDS shall
be used. When spaced 12 inches (305 mm) on center, an
Fb of not less than 875 psi (6033 kPa) shall be required.
For wood foundations that are not designed and installed in accordance with AWC PWF, the height of backfill against a foundation wall shall not exceed 4 feet (1219 mm). When the height of fill is more than 12 inches (305 mm) above the interior grade of a crawl space or floor of a basement, the thickness of the plywood sheathing shall meet the requirements of Table R404.2.3.
TABLE R404.2.3 PLYWOOD GRADE AND THICKNESS FOR WOOD FOUNDATION CONSTRUCTION (30 pcf equivalent-fluid weight soil pressure)
Where a major portion of the wall is exposed above ground and a better appearance is desired, the following plywood grades marked exterior are suitable:
Structural I A-C, Structural I B-C or Structural I C-C (Plugged) in accordance with DOC PS 1.
A-C Group 1, B-C Group 1, C-C (Plugged) Group 1 or MDO Group 1 in accordance with DOC PS 1.
Single Floor in accordance with DOC PS 1 or DOC PS 2.
Minimum thickness 15/32 inch, except crawl space sheathing shall have not less than 3/8 inch for face grain across studs 16 inches on center and maximum 2-foot depth of unequal fill.
For this fill height, thickness and grade combination, panels that are continuous over less than three spans (across less than three stud spacings) require blocking 16 inches above the bottom plate. Offset adjacent blocks and fasten through studs with two 16d corrosion-resistant nails at each end.
Wood foundation walls shall not be
backfilled until the basementfloor and first floor have
been constructed or the walls have been braced. For crawl
space construction, backfill or bracing shall be installed on
the interior of the walls prior to placing backfill on the
exterior.
Wood sill plates shall be a minimum
of 2-inch by 4-inch (51 mm by 102 mm) nominal lumber.
Sill plate anchorage shall be in accordance with Sections
R403.1.6 and R602.11.
Retaining walls that are not laterally
supported at the top and that retain in excess of 48 inches
(1219 mm) of unbalanced fill, or retaining walls exceeding 24
inches (610 mm) in height that resist lateral loads in addition
to soil, shall be designed in accordance with accepted engineering
practice to ensure stability against overturning, sliding,
excessive foundation pressure and water uplift. Retaining
walls shall be designed for a safety factor of 1.5 against lateral
sliding and overturning. This section shall not apply to
foundation walls supporting buildings.
Precast concrete foundation walls shall
be designed in accordance with accepted engineering practice.
The design and manufacture of precast concrete foundation
wall panels shall comply with the materials
requirements of Section R402.3 or ACI 318. The panel
design drawings shall be prepared by a registered design
professional where required by the statutes of the jurisdiction
in which the project is to be constructed in accordance
with Section R106.1.
Precast concrete foundation wall design drawings shall be submitted to the building official and approvedprior to installation. Drawings shall include, at a minimum, the following information:
Design loading as applicable.
Footing design and material.
Concentrated loads and their points of application.
Drains shall be
provided around concrete or masonry foundations that retain
earth and enclose habitable or usable spaces located below
grade. Drainage tiles, gravel or crushed stone drains, perforated
pipe or other approvedsystems or materials shall be
installed at or below the area to be protected and shall discharge
by gravity or mechanical means into an approved
drainage system. Gravel or crushed stone drains shall extend
not less than 1 foot (305 mm) beyond the outside edge of the
footing and 6 inches (152 mm) above the top of the footing and
be covered with an approvedfilter membrane material. The
top of open joints of drain tiles shall be protected with strips of
building paper. Except where otherwise recommended by the
drain manufacturer, perforated drains shall be surrounded with
an approvedfilter membrane or the filter membrane shall
cover the washed gravel or crushed rock covering the drain.
Drainage tiles or perforated pipe shall be placed on a minimum
of 2 inches (51 mm) of washed gravel or crushed rock not less
than one sieve size larger than the tile joint opening or perforation and covered with not less than 6 inches (152 mm) of the
same material.
Exception:
A drainage system is not required where the
foundation is installed on well-drained ground or sand-gravel
mixture soils according to the Unified Soil Classification
System, Group I soils, as detailed in Table R405.1.
TABLE R405.1 PROPERTIES OF SOILS CLASSIFIED ACCORDING TO THE UNIFIED SOIL CLASSIFICATION SYSTEM
SOIL Group
UNIFIED SOIL CLASSIFICATION SYSTEM SYMBOL
SOIL DESCRIPTION
DRAINAGE CHARACTERISTICSa
FROST HEAVE POTENTIAL
VOLUME CHANGE POTENTIAL EXPANSIONb
Group I
GW
Well-graded gravels, gravel sand mixtures little or no fines
Good
Low
Low
GP
Poorly graded gravels or gravel sand mixtures, little or no fines
Good
Low
Low
SW
Well-graded sands, gravelly sands, little or no fines
Good
Low
Low
SP
Poorly graded sands or gravelly sands, little or no fines
Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts
Poor
High
High
Group IV
OL
Organic silts and organic silty clays of low plasticity
Poor
Medium
Medium
OH
Organic clays of medium to high plasticity, organic silts
Unsatisfactory
Medium
High
Pt
Peat and other highly organic soils
Unsatisfactory
Medium
High
For SI: 1 inch = 25.4 mm.
The percolation rate for good drainage is over 4 inches per hour, medium drainage is 2 inches to 4 inches per hour, and poor is less than 2 inches per hour.
Soils with a low potential expansion typically have a plasticity index (PI) of 0 to 15, soils with a medium potential expansion have a PI of 10 to 35 and soils with a high potential expansion have a PI greater than 20.
Precast concretewalls that retain earth and enclose habitable or useable
space located below-gradethat rest on crushed stone footings
shall have a perforated drainage pipe installed below
the base of the wall on either the interior or exterior side of
the wall, not less than 1 foot (305 mm) beyond the edge of
the wall. If the exterior drainage pipe is used, an approved
filter membrane material shall cover the pipe. The drainage
system shall discharge into an approvedsewer system
or to daylight.
Wood foundations enclosing
habitable or usable spaces located below gradeshall be adequately
drained in accordance with Sections R405.2.1
through R405.2.3.
A porous layer of gravel, crushed stone or
coarse sand shall be placed to a minimum thickness of 4
inches (102 mm) under the basementfloor. Provision shall
be made for automatic draining of this layer and the gravel
or crushed stone wall footings.
In other than Group I soils, a
sump shall be provided to drain the porous layer and footings.
The sump shall be not less than 24 inches (610 mm)
in diameter or 20 inches square (0.0129 m2), shall extend
not less than 24 inches (610 mm) below the bottom of the
basementfloor and shall be capable of positive gravity or
mechanical drainage to remove any accumulated water.
The drainage system shall discharge into an approved
sewer system or to daylight.
Except where required by Section R406.2 to be waterproofed,
foundation walls that retain earth and enclose interior spaces
and floors below gradeshall be dampproofed from the higher
of (a) the top of the footing or (b) 6 inches (152 mm) below the
top of the basement floor, to the finished grade. Masonry walls
shall have not less than 3/8 inch (9.5 mm) portland cement parging applied to the exterior of the wall. The parging shall be
dampproofed in accordance with one of the following:
Bituminous coating.
Three pounds per square yard (1.63 kg/m2) of acrylic
modified cement.
One-eighth-inch (3.2 mm) coat of surface-bonding
cement complying with ASTM C887.
Any material permitted for waterproofing in Section
R406.2.
Exception:
Parging of unit masonry walls is not required where a material is approved for direct application to the masonry.
Concretewalls shall be dampproofed by applying any one
of the listed dampproofing materials or any one of the waterproofing
materials listed in Section R406.2 to the exterior of
the wall.
In areas where a high water table or other severe soil-water
conditions are known to exist, exterior foundation walls that
retain earth and enclose interior spaces and floors below
gradeshall be waterproofed from the higher of (a) the top of
the footing or (b) 6 inches (152 mm) below the top of the
basement floor, to the finished grade. Walls shall be waterproofed
in accordance with one of the following:
Exception: Organic-solvent-based products such as
hydrocarbons, chlorinated hydrocarbons, ketones and esters
shall not be used for ICFwalls with expanded polystyrene
form material. Use of plastic roofing cements, acrylic
coatings, latex coatings, mortars and pargings to seal ICFwalls is permitted. Cold-setting asphalt or hot asphalt shall
conform to Type C of ASTM D449. Hot asphalt shall be
applied at a temperature of less than 200°F (93°C).
All joints in membrane waterproofing shall be lapped and
sealed with an adhesive compatible with the membrane.
Plywood panel joints in the
foundation walls shall be sealed full length with a caulking
compound capable of producing a moistureproof seal
under the conditions of temperature and moisture content
at which it will be applied and used.
A 6-mil-thick
(0.15 mm) polyethylene film shall be applied over the
below-gradeportion of exterior foundation walls prior to
backfilling. Joints in the polyethylene film shall be lapped
6 inches (152 mm) and sealed with adhesive. The top edge
of the polyethylene film shall be bonded to the sheathing to
form a seal. Film areas at gradelevel shall be protected
from mechanical damage and exposure by a pressure-preservative
treated lumber or plywood strip attached to the
wall several inches above finished gradelevel and extending approximately 9 inches (229 mm) below grade. The
joint between the strip and the wall shall be caulked full
length prior to fastening the strip to the wall. Where
approved, other coverings appropriate to the architectural
treatment shall be permitted to be used. The polyethylene
film shall extend down to the bottom of the wood footing
plate but shall not overlap or extend into the gravel or
crushed stone footing.
The space between the excavation
and the foundation wall shall be backfilled with the same
material used for footings, up to a height of 1 foot (305
mm) above the footing for well-drained sites, or one-half
the total back-fill height for poorly drained sites. The
porous fill shall be covered with strips of 30-pound (13.6
kg) asphalt paper or 6-mil (0.15 mm) polyethylene to permit
water seepage while avoiding infiltration of fine soils.
Precast concrete foundation
panel joints shall be sealed full height with a sealant meeting
ASTM C920, Type S or M, GradeNS, Class 25, Use
NT, M or A. Joint sealant shall be installed in accordance
with the manufacturer's instructions.
All surfaces (inside and
outside) of steel columns shall be given a shop coat of rustinhibitive
paint, except for corrosion-resistant steel and steel
treated with coatings to provide corrosion resistance.
The columns shall be
restrained to prevent lateral displacement at the bottom end.
Wood columns shall be not less in nominal size than 4 inches
by 4 inches (102 mm by 102 mm). Steel columns shall be not
less than 3-inch-diameter (76 mm) Schedule 40 pipe manufactured
in accordance with ASTM A53 Grade B or approved
equivalent.
Exception: In Seismic Design Categories A, B and C, columns
not more than 48 inches (1219 mm) in height on a
pier or footing are exempt from the bottom end lateral displacement
requirement within under-floor areas enclosed
by a continuous foundation.
The under-floor space between the bottom
of the floor joists and the earth under any building
(except space occupied by a basement) shall have ventilation
openings through foundation walls or exterior walls. The minimum net area of ventilation openings shall be not less
than 1 square foot (0.0929 m2) for each 150 square feet (14
m2) of under-floor space area, unless the ground surface is
covered by a Class 1 vapor retarder material. Where a Class 1
vapor retarder material is used, the minimum net area of ventilation
openings shall be not less than 1 square foot (0.0929
m2) for each 1,500 square feet (140 m2) of under-floor space
area. One such ventilating opening shall be within 3 feet (914
mm) of each corner of the building.
The minimum
net area of ventilation openings shall be not less than 1
square foot (0.0929 m2) for each 150 square feet (14 m2) of
under-floor area. One ventilation opening shall be within 3
feet (915 mm) of each corner of the building. Ventilation
openings shall be covered for their height and width with any
of the following materials provided that the least dimension
of the covering shall not exceed 1/4 inch (6.4 mm):
Perforated sheet metal plates not less than 0.070 inch
(1.8 mm) thick.
Expanded sheet metal plates not less than 0.047 inch
(1.2 mm) thick.
Hardware cloth of 0.035 inch (0.89 mm) wire or heavier.
Corrosion-resistant wire mesh, with the least dimension
being 1/8 inch (3.2 mm) thick.
Exception: The total area of ventilation openings shall be
permitted to be reduced to 1/1,500 of the under-floor area
where the ground surface is covered with an approved
Class I vapor retarder material and the required openings
are placed to provide cross ventilation of the space. The
installation of operable louvers shall not be prohibited.
Ventilation openings in
under-floor spaces specified in Sections R408.1 and R408.2
shall not be required where the following items are provided:
Exposed earth is covered with a continuous Class I
vapor retarder. Joints of the vapor retarder shall overlap
by 6 inches (152 mm) and shall be sealed or taped. The
edges of the vapor retarder shall extend not less than 6
inches (152 mm) up the stem wall and shall be attached
and sealed to the stem wall or insulation.
One of the following is provided for the under-floor
space:
2.1. Continuously operated mechanical exhaust ventilation
at a rate equal to 1 cubic foot per minute
(0.47 L/s) for each 50 square feet (4.7 m2) of
crawl space floor area, including an air pathway
to the common area (such as a duct or transfer
grille), and perimeter walls insulated in accordance
with Section N1102.2.11 of this code.
2.2. Conditioned air supply sized to deliver at a rate
equal to 1 cubic foot per minute (0.47 L/s) for
each 50 square feet (4.7 m2) of under-floor area, including a return air pathway to the common
area (such as a duct or transfer grille), and
perimeter walls insulated in accordance with
Section N1102.2.11 of this code.
2.3. Plenum in existing structures complying with
Section M1601.5, if under-floor space is used as
a plenum.
Access shall be provided to all under-floor
spaces. Access openings through the floor shall be a minimum
of 18 inches by 24 inches (457 mm by 610 mm). Openings
through a perimeter wall shall be not less than 16 inches
by 24 inches (407 mm by 610 mm). Where any portion of the
through-wall access is below grade, an areaway not less than
16 inches by 24 inches (407 mm by 610 mm) shall be provided.
The bottom of the areaway shall be below the threshold
of the access opening. Through wall access openings shall
not be located under a door to the residence. See Section
M1305.1.4 for access requirements where mechanical equipment
is located under floors.
The under-floor gradeshall be
cleaned of all vegetation and organic material. All wood
forms used for placing concrete shall be removed before a
building is occupied or used for any purpose. All construction
materials shall be removed before a building is occupied or
used for any purpose.
The finished gradeof under-floor
surface shall be permitted to be located at the bottom of the
footings; however, where there is evidence that the groundwater
table can rise to within 6 inches (152 mm) of the finished
floor at the building perimeter or where there is
evidence that the surface water does not readily drain from
the building site, the gradein the under-floor space shall be
as high as the outside finished grade, unless an approved
drainage system is provided.
For SI: 1 foot = 304.8 mm.
