SECTION 748:20-5-7. IRC® 2015 Chapter 4 Foundations

  Chapter 4 of the IRC® 2015 is adopted with the following modifications:

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

(2)   Table R403.1(1) Minimum width and thickness for concrete footings for light-frame construction (inches). This table has been modified to strike footnote "b" from underneath the table. The footnote area at the bottom of the table has been amended to read: a. Interpolation allowed. Extrapolation is not allowed.

(3)   Table R403.1(2) Minimum width and thickness for concrete footings for light-frame construction with brick veneer (inches). This table has been modified to strike footnote "b" from underneath the table. The footnote area at the bottom of the table has been amended to read: a. Interpolation allowed. Extrapolation is not allowed.

(4)   Table R403.1(3) Minimum width and thickness for concrete footings with cast-in-place concrete or fully grouted masonry wall construction (inches). This table has been modified to strike footnote "b" from underneath the table. The footnote area at the bottom of the table has been amended to read: a. Interpolation allowed. Extrapolation is not allowed.

(5)   Figure R403.1(1) Plain concrete footings with masonry and concrete stem walls in SDC A, B, and C. The figure heading has been amended to include a superscript "g" to indicate an associated footnote. The "Notes" area at the bottom of this figure has been modified to add a note "g" to require reinforcement in the footings of structures in SDC A, B, and C. The "Notes" at the bottom of the figure have been amended to read:

(A)   a. See Section 404.3 for sill requirements.

(B)   b. See Section 403.1.6 for sill attachment.

(C)   c. See Section R506.2.3 for vapor barrier requirements.

(D)   d. See Section R403.1. for base.

(E)   e. See Figure R403.1.3 for additional footing requirements for structures in SDC D0, D1, and D2 and townhouses in SDC C.

(F)   f. See Section R408 for under-floor ventilation and access requirements.

(G)   g. Add two number four (4) rebar to all footings. Additionally all cold joints between footings and foundation walls (stem walls) shall be tied together by a number four (4) rebar at every corner and not to exceed 6 feet (1828 mm) o.c. with embedment of 12 inches (304 mm) into each footing and wall.

(6)   Section R403.1.6 Foundation anchorage. This section has been modified to specify hand driven cut and concrete nails are not an approved fastener and include an exception for wood sole plates of braced wall panels anchorage under specific criteria. This section has been modified to read:

(A)   R403.1.6 Foundation anchorage: Wood sill plates and wood walls supported directly on continuous foundations shall be anchored to the foundation in accordance with this section.

(B)   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 shall be in accordance with this section and Section R505.3.1 or R603.3.1.

(C)   Wood sole plates at the 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-inch-diameter (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 concrete masonry 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 that are not part of a braced wall panel shall be positively anchored with approved fasteners. Hand driven cut or concrete nails are not approved fasteners. Sill plates and sole plates shall be protected against decay and termites where required by Section R317 and R318. Exceptions:

(i)   Walls 24 inches (610 mm) total length or shorter connecting offset braced 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).

(ii)   Connection of walls 12 inches (305 mm) total length or shorter connecting offset braced wall panels to the foundation without anchor bolts shall be permitted. The wall shall be attached at corners as shown in Item 9 of Table R602.3(1).

(iii)   Wood sole plates of braced wall panels at building interiors on monolithic slabs may be anchored using connector(s) with a shear capacity of 2300 pounds and a tensile capacity of 800 pounds over a maximum span of 6 feet.

(7)   Section R403.1.7.3 Foundation Elevation. This section has been stricken from the code.

(8)   Section R403.1.9. Protection of footings. This section has been added to provide protection to footings when trenching work is needed. This section has been added to read: R403.1.9. Protection of footings. Trenching for work including but not limited to plumbing, electrical, storm shelters, and pools shall comply with this section. Trenching installed parallel to footings and walls shall not extend into the bearing plane of a footing wall. The upper boundary of the bearing plane is a line that extends downward, at an angle of 45 degrees from horizontal, from the outside bottom edge of the footing wall.

(9)   Section R406.2 Concrete and masonry foundation waterproofing. This section has been modified to include an additional option for waterproofing. This section has been modified to read:

(A)   R406.2 Concrete and masonry foundation waterproofing. 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 grade shall 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:

(i)   Two-ply hot-mopped felts.

(ii)   Fifty-five-pound (25 kg) roll roofing.

(iii)   Six-mil (0.15 mm) polyvinyl chloride.

(iv)   Six-mil (0.15 mm) polyethylene.

(v)   Forty-mil (1 mm) polymer-modified asphalt.

(vi)   Sixty-mil (1.5 mm) flexible polymer cement.

(vii)   One-eighth-inch (3 mm) cement-based, fiber-reinforced waterproof coating.

(viii)   Sixty-mil (1.5 mm) solvent-free liquid-applied synthetic rubber.

(ix)   Bentonite.

(B)   Exception: Organic-solvent-based products such as hydrocarbons, chlorinated hydrocarbons, ketones and esters shall not be used for ICF walls with expanded polystyrene form material. Use of plastic roofing cements, acrylic coatings, latex coatings, mortars, and pargings to seal ICF walls is permitted. Cold-setting asphalt or hot asphalt shall conform to Type C of ASTM D 449. Hot asphalt shall be applied at a temperature of less than 200 degrees Fahrenheit (93 degrees Celsius).

(C)   All joints in membrane waterproofing shall be lapped and sealed with an adhesive compatible with the membrane.

[Source: Added at 28 Ok Reg 2122, eff 7-15-11; Amended at 33 Ok Reg 1852, eff 11-1-16]