Simi Valley Municipal Code Ch. 23 Adoption and Amendments of the California Residential Code

(a) The California Residential Code, 2025 Edition, Part 2.5 of Title 24 of the California Code of Regulations together with those omissions, amendments, exceptions and additions thereto are hereby adopted and enacted, as the Primary Building Code of the City of Simi Valley and made part of this Code by reference with the same force and effect as if fully set forth herein.

(b) One copy of the 2025 California Residential Code has been filed for use and examination of the public in the Offices of the City of Simi Valley.

(§ 1(Exh. A), Ord. No. 1366, eff. December 18, 2025)

The following portions of the California Residential Code, are not approved or adopted or incorporated in this Chapter by reference, and shall not be deemed to be a part of this Chapter nor a part of the building code of the City of Simi Valley:

(a) Chapter 1 Division II, Administration.

(§ 2 (Exh. A), Ord. No. 1346, eff. January 5, 2023)

The provisions of this Chapter contain cross-references to the provisions of the California Residential Code, in order to facilitate reference and comparison to those provisions.

(§ 2 (Exh. A), Ord. No. 1346, eff. January 5, 2023)

The provisions of this Chapter shall constitute local amendments to the cross-referenced provisions of the California Residential Code and shall be deemed to replace the cross-referenced section of the California Residential Code with the respective provisions set forth in this Chapter.

SECTION R301 DESIGN CRITERIA.

This section is hereby amended to read as follows:

R301.1.3.2 Woodframe structures. The Building Official shall require construction documents to be designed, approved and stamped by a California licensed architect or engineer for all dwellings of woodframe construction more than one story in height or with a basement located in Seismic Design Category D 0 , D 1 , D 2 , or E

FINDINGS:

Local Geological Conditions - The City of Simi Valley, greater Ventura County area, and southern California region is a densely populated area having buildings constructed over and near a vast array of fault systems capable of producing major earthquakes, including but not limited to the 1994 Northridge Earthquake. Conventional framing does not address the need for a continuous load path, critical shear transfer mechanisms, connection ties, irregular and flexible portions of complex shaped structures. Unless designed by a registered design professional, such buildings built by conventional framing requirements will be prone to serious damage in future large earthquakes. This modification shall be incorporated into the Code to assure that new buildings and additions to existing buildings are designed and constructed in accordance with the scope and objectives of the California Building Code. For this reason, this jurisdiction determines that these amendments are reasonably necessary.

SECTION R401 GENERAL.

This section is hereby amended to read as follows:

R401.1 Application. The provisions of this Chapter shall control the design and construction of the foundation and foundations spaces for all buildings. In addition to the provisions of this Chapter, the design and construction of foundations in areas prone to flooding as established by Table R301.2(1) shall meet the provisions of section R322.

Wood foundations in Seismic Design Category D 0 , D 1 , D 2 or E shall not be permitted.

SECTION R403 FOOTINGS.

This section is hereby amended to read as follows:

R403.1.1 Minimum Size. Prescriptive reinforced concrete footings for one or two story woodframed residential buildings shall be dimensioned in accordance with Chapter 11 Section 1809.7 of this Code.

Minimum size of hold-down anchor bolt for braced wall panels shall be one-half (½) inch diameter.

R403.1.2 Continuous footing in Seismic Design Categories D0, D1, D2or E. The braced wall panels at exterior walls of buildings located in Seismic Design Categories D0, D1, D2 or E shall be supported by continuous footings. All required interior braced wall panels in buildings shall be supported by continuous footings.

R403.1.3 Seismic Reinforcing. Concrete footings located in Seismic Design Categories D0, D1, D2 or E shall have minimum reinforcement. Bottom reinforcement shall be located a minimum of 3 inches (76 mm) clear from the bottom of the footing.

In Seismic Design Categories D0, D1, D2 or E where a construction joint is created between a concrete footing and a stem wall, a minimum of one (1) No. 4 bar shall be installed at not more than 4 feet (1219 mm) on center. The vertical bar shall extend to 3 inches (76 mm) clear of the bottom of the footing, have a standard hook and extend a minimum of 14 inches (357 mm) into the stem wall.

FINDINGS:

Local Geological, Topographic Conditions - The City of Simi Valley, the greater Ventura County area, and the southern California region is a densely populated area having buildings constructed over and near a vast array of fault systems capable of producing major earthquakes, including but not limited to the 1994 Northridge Earthquake. The City contains areas designated as flood zones, liquefaction, and landslide hazards. These amendments are required to address and clarify special needs to reduce hazards resulting from liquefaction or soil displacement due to strong seismic events. This modification to improve design and construction methods for foundations of residential structures shall be incorporated into the Code to assure that new buildings and additions to existing buildings are designed and constructed in accordance with the scope and objectives of the California Building Code. For this reason, this jurisdiction determines that these amendments are reasonably necessary.

SECTION R601 GENERAL.

This section is hereby amended to read as follows:

R601.1 Application. The provisions of this Chapter shall control the design and construction of all walls and partitions for all buildings.

Notwithstanding any other provisions of this Code, gypsum lath, gypsum sheathing, gypsum board, Portland cement plaster, fiberboard, or particle board shall not be used as a structural material or structural component to resist seismic forces in shear walls, braced wall panels, vertical diaphragms or other similar seismic resisting elements. When materials are substantiated by cyclic testing, demonstrating the necessary strength and ductility, and are approved by the Building Official, such materials may be used to resist seismic forces.

The wood structural panel shear walls using staples as fasteners shall not be permitted unless the structural panel assembly is substantiated by cyclic testing, and approved by the Building Official.

Wall bracing method for seismic design categories D 2 and E shall be CS-WSP, with a minimum thickness of one-half (1/2) inch.

Minimum length of any individual braced wall panel shall not be less than thirty-six (36) inches for seismic design categories D 2 or E.

Minimum total length of braced wall panels along each braced wall line shall be in accordance with Table R602.10.3(3) for seismic design category D 2 .

FINDINGS:

Local Geological Conditions - The City of Simi Valley, the greater Ventura County area, and southern California region is a densely populated area having buildings constructed over and near a vast array of fault systems capable of producing major earthquakes, including but not limited to the 1994 Northridge Earthquake. Gypsum wallboard, exterior Portland cement plaster, and similar wall construction techniques and materials lacking adequate ductility, and deformation characteristics, have performed poorly during California seismic events. (Such as Loma Prieta and Northridge.) The shear values for gypsum wallboard, Portland cement stucco, fiberboard and staple fasteners contained in the Code are based on mono-directional testing only. The limitation on the use of these systems as set forth in the amendment until cyclic loading testing are performed and evaluated in a more rigorous standard which will better prevent damage to a structure's lateral load resisting system which can result from local conditions. This modification is incorporated into the Code to assure that new buildings and additions to existing buildings are designed and constructed in accordance with the scope and objectives of the California Building Code. For this reason, this jurisdiction determines that these amendments are reasonably necessary.

(§ 2 (Exh. A), Ord. No. 1346, eff. January 5, 2023)