Article 1.5 — , DIVISION 4

[FOUNDATIONS]

Section

91.5.400 Basic Provisions.

SEC. 91.5.400. BASIC PROVISIONS.

Chapter 4 of the CRC is hereby adopted by reference with the following exceptions, modifications and additions.

91.5.401.1. Application. The provisions of this Division shall control the design and construction of the foundation and foundation spaces for all buildings. In addition to the provisions of this division, the design and construction of foundations in flood hazard areas as established by CRC Table R301.2(1) shall meet the provisions of CRC Section R322. Wood foundations shall be designed and installed in accordance with AF&PA PWF. (Amended by Ord. No. 185,587, Eff. 7/16/18.)

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;
When 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 not be permitted.

Exception: In non-occupied, single-story, detached storage sheds and similar uses other than carport or garage, provided the gross floor area does not exceed 200 square feet, the plate height does not exceed 12 feet in height above the grade at any point, and the maximum roof projection does not exceed 24 inches.

91.5.403.1.2. Continuous Footing in Seismic Design Categories D0, D1, D2. 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. All required interior braced wall panels in buildings located in Seismic Design Categories D0, D1, and D2 shall be supported on foundations. (Amended by Ord. No. 184,692, Eff. 12/30/16.)

91.5.403.1.3.6. Isolated Concrete Footings. In detached one- and two-family dwellings located in Seismic Design Category A, B or C that are three stories or less in height and constructed with stud bearing walls, isolated plain concrete footings supporting columns or pedestals are permitted in accordance with CRC Section R403.1.3.4. (Added by Ord. No. 184,692, Eff. 12/30/16.)

91.5.403.1.5. Slope. 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 ten units horizontal (10-percent slope).

For structures located in Seismic Design Categories D0, D1, and D2, or E, stepped footings shall be reinforced with four 1/2-inch diameter (12.7 mm) deformed reinforcing bars. Two bars shall be placed at the top and bottom of the footing as shown in figure 91.5.403.1.5.

Figure 91.5.403.1.5 Stepped Footing

91.5.404.2. Wood Foundation Walls. Wood foundation walls shall be constructed in accordance with the provisions of CRC Sections R404.2.1 through R404.2.6 and with the details shown in CRC Figures R403.1(2) and R403.1(3). Wood foundation walls shall not be used for structures located in Seismic Design Category D0, D1, or D2. (Amended by Ord. No. 185,587, Eff. 7/16/18.)