§ 16.06.240. Section R403.1.8 - Foundations on expansive soils.

Section R403.1.8 of the California Residential Code is amended to read:

R403.1.8 Foundations on expansive soils. Foundations and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1808.6 or Table 1809.7 of the California Building Code.

TABLE 1809.7

Prescriptive Footings Supporting Walls of Light-Frame Constructionabcd

Number of Floors Supported by the Footing e	Thickness of Foundation Wall (inches)	Width of Footing (inches)	Thickness of Footing (inches)	Depth of Foundation Below Natural Surface of Ground or Finish Grade (inches)
1 & 2	8	15	8	20
3	8	18	8	30
Group U Occupancies	8	12	8	12

a) The ground under the floor shall be permitted to be excavated to the elevation of the top of the footing.

b) Interior stud-bearing walls shall be permitted to be supported by isolated footings. The footing width and length shall be twice the width shown in this table, and footings shall be spaced not more than 6 feet on center.

c) See Section 1905 of California Building Code for additional requirements for concrete footings of structures assigned to Seismic Design Category C, D, E or F.

d) All foundations as required in the above Table shall be continuous and have a minimum of three #4 bars of reinforcing steel, except for one story, detached accessory buildings of Group U occupancy where two bars are required.

e) Footings shall be permitted to support a roof in addition to the stipulated number of floors. Footings supporting roof only shall be as required for supporting one floor.

(Ord. 5479 § 1 (part), 2019)