Chapter 16.19 — CALIFORNIA HISTORICAL BUILDING CODE, CALIFORNIA CODE OF

REGULATIONS, TITLE 24, PART 8 AND CALIFORNIA EXISTING BUILDING CODE, CALIFORNIA CODE OF REGULATIONS, TITLE 24, PART 10*

Sections

16.19.010 2025 California Historical Building Code, Title 24, Part 8 adopted.

16.19.020 2025 California Existing Building Code, Title 24, Part 10 adopted and amended.

• Editor’s Note: Prior ordinance history: Ordinance No. 5564

16.19.010 2025 California Historical Building Code, Title 24, Part 8 adopted.

The California Historical Building Code, 2025 Edition, Title 24, Part 8 (authorized by Health and Safety Code Sections 18950 through 18961), which provides alternative building regulations for the rehabilitation, preservation, restoration, or relocation of designated historic buildings, is adopted and hereby incorporated in this chapter by reference and made a part hereof the same as if fully set forth herein.

One copy of the California Historical Building Code, 2025 Edition, has been filed for use and examination of the public in the Office of the Chief Building Official of the City of Palo Alto.

(Ord. 5674 § 2 (part), 2025)

16.19.020 2025 California Existing Building Code, Title 24, Part 10 adopted and amended.

The California Existing Building Code, 2025 Edition, Title 24, Part 10 of the California Code of Regulations, which provides alternative building regulations for the rehabilitation, preservation restoration or relocation of existing buildings, together with those omissions, amendments, exceptions, and additions thereto, is adopted and hereby incorporated in this chapter by reference and made a part hereof the same as if fully set forth herein.

One copy of the California Existing Building Code, 2025 Edition, has been filed for use and examination of the public in the Office of the Chief Building Official of the City of Palo Alto.

(Ord. 5674 § 2 (part), 2025)

The provisions of this chapter contain cross-references to the provisions of the California Existing Building Code, 2025 Edition, in order to facilitate reference and comparison to those provisions.

(Ord. 5674 § 2 (part), 2025)

The provisions of this chapter shall constitute local amendments to the cross-referenced provisions of the California Existing Building Code, 2025 Edition, and shall be deemed to replace the cross-referenced sections of said Code with the respective provisions set forth in this chapter.

(Ord. 5674 § 2 (part), 2025)

16.19.050 101.2.1 Appendices.

Section 101.2.1 of Chapter 1 of the California Existing Building Code is amended to read:

2025 California Existing Building Code and International Existing Building Code Appendix Chapters Adopted.The following Appendix Chapters of the California Existing Building Code (CEBC), 2025 Edition, and International Existing Building Code (IEBC), 2024 Edition, are adopted and hereby incorporated in this chapter be reference and made a part hereof the same as if fully set forth herein:

A. CEBC Appendix A1 – Seismic Strengthening Provisions for Unreinforced Masonry Bearing Wall Buildings.

B. CEBC Appendix Chapter A2 – Earthquake Hazard Reduction in Existing Reinforced Concrete and Reinforced Masonry Wall Buildings with

Flexible Diaphragms.

C. CEBC Appendix A3 – Prescriptive Provisions for Seismic Strengthening of Cripple Walls and Sill Plate Anchorage of Light, Wood-Frame Residential Buildings.

D. CEBC Appendix A4 – Earthquake Risk Reduction in Wood-Frame Residential Buildings with Soft, Weak or Open Front Walls.

E. CEBC Appendix A5 – Referenced Standards.

(Ord. 5674 § 2 (part), 2025)

Administration and enforcement of this code shall be governed by Chapter 1, Division II of the 2025 California Building Code as amended by Palo Alto Municipal Code Chapter 16.04.

(Ord. 5674 § 2 (part), 2025)

Chapter 1, Division II, Parts 1 and 2 of the 2025 California Existing Building Code is adopted by the City of Palo Alto to supplement, to the extent it does not conflict with, Chapter 1, Division II of the 2025 California Building Code, as amended.

(Ord. 5674 § 2 (part), 2025)

Section 101.1 of Chapter 1 of the California Existing Building Code is amended to read:

101.1 Title. These regulations shall be known as the Existing Building Code of City of Palo Alto, hereinafter referred to as "this code."

(Ord. 5674 § 2 (part), 2025)

Section 324 of Chapter 3 of the California Existing Building Code is added to read:

324 Dwelling unit and congregate residence superficial floor area. Every dwelling unit and congregate residence shall have at least one room which shall have not less than 120 square feet of superficial floor area. Every room which is used for both cooking and living or both living and sleeping purposes shall have not less than 144 square feet of superficial floor area. Every room used for sleeping purposes shall have not less than 70 square feet of superficial floor area. When more than two persons occupy a room used for sleeping purposes the required superficial floor area shall be increased at the rate of 50 square feet for each occupant in excess of two. Guest rooms with cooking shall contain the combined required superficial areas of a sleeping and a kitchen, but not less than 144 square feet. Other habitable rooms shall be not less than 70 square feet.

Notwithstanding any provision of this section, children under the age of six shall not be counted for purposes of determining whether a family with minor children complies with the provisions of this Code.

For the purposes of this section, "superficial floor area" means the net floor area within the enclosing walls of the room in which the ceiling height is not less than seven feet six inches, excluding built-in equipment such as wardrobes, cabinets, kitchen units, or fixtures which are not readily removable.

(Ord. 5674 § 2 (part), 2025)

Section 503.21 of Chapter 5 the California Existing Building Code is added to read:

503.21 Suspended ceiling systems. In existing buildings or structures, when a permit is issued for alterations or repairs, the existing suspended ceiling system within the area of the alterations or repairs shall comply with ASCE 7-22 Section 13.5.6.

(Ord. 5674 § 2 (part), 2025)

Section 503.22 of Chapter 5 of the California Existing Building Code is added to read:

503.22 Mechanical and electrical equipment in seismic design categories D, E or F.In existing buildings or structures, when a permit is

issued for alteration or repairs, the existing mechanical and electrical equipment on the area of the roof shall comply with ASCE 7-22 Section 13.4 Nonstructural Component Anchorage.

(Ord. 5674 § 2 (part), 2025)

Section 405.2.3.1 of Chapter 5 of the California Existing Building Code is amended to read:

405.2.3.1 Evaluation and design procedures. The building shall be evaluated by a registered design professional, and the evaluation findings

shall be submitted to the code official. The evaluation shall establish whether the damaged building, if repaired to its pre-damage state, would comply with the provisions of the California Building Code for load combinations that include wind or earthquake effects, except that the seismic forces shall be reduced seismic forces. Evaluation for earthquake loads shall be required if the substantial structural damage was caused by or related to earthquake effects or if the building is in Seismic Design Category C, D, E or F. The seismic evaluation and design shall be based on the procedures specified in the building code, ASCE 41 Seismic Evaluation and Upgrade of Existing Buildings. The procedures contained in Appendix A of the International Existing Building Code (IEBC) shall be permitted to be used as specified in Section 405.2.3.1.

Wind loads for this evaluation shall be those prescribed in Section 1609.

405.2.3.1.1 CEBC level seismic forces. When seismic forces are required to meet the building code level, they shall be one of the following:

1. One hundred percent of the values in the building code. The R factor used for analysis in accordance with Chapter 16 of the building code

shall be the R factor specified for structural systems classified as "Ordinary" unless it can be demonstrated that the structural system satisfies the proportioning and detailing requirements for systems classified as "intermediate" or "special".

2. Forces corresponding to BSE-1 and BSE-2 Earthquake Hazard Levels defined in ASCE 41. Where ASCE 41 is used, the corresponding

performance levels shall be those shown in Table 405.2.3.1.

3. Forces corresponding to BSE-1 and BSE-2 Earthquake Hazard Levels defined in ASCE 41. Where ASCE 41 is used, the corresponding

performance levels shall be those shown in Table 405.2.3.1.

TABLE 405.2.3.1

ASCE 41 PERFORMANCE LEVELS

PERFORMANCE LEVEL FOR USE WITH PERFORMANCE LEVEL FOR USE WITH

RISK CATEGORY (BASED ON CBC TABLE ASCE 41 BSE-1 EARTHQUAKE HAZARD ASCE 41 BSE-2 EARTHQUAKE HAZARD 1604.5) LEVEL LEVEL *

I Life Safety (LS) Collapse Prevention (CP) II Life Safety (LS) Collapse Prevention (CP) III Damage Control Limited Safety IV Immediate Occupancy (IO) Life Safety (LS)

• Only applicable when Tier 3 procedure is used.

  405.2.3.1.2 Reduced CEBC level seismic forces. When seismic forces are permitted to meet reduced building code levels, they shall be one of the following:

  1. Seventy-five percent of the forces prescribed in the building code. The R factor used for analysis in accordance with Chapter 16 of the building code shall be the R factor as specified in Section 405.2.3.1.1.

  2. In accordance with the California Existing Building Code and applicable chapters in Appendix A of the International Existing Building Code, as specified in Items (a.) through (e.) below. Structures or portions of structures that comply with the requirements of the applicable chapter in Appendix A shall be deemed to comply with the requirements for reduced building code force levels.

  a. The seismic evaluation and design of unreinforced masonry bearing wall buildingsin Risk Category I or II are permitted to be based on

the procedures specified in CEBC Appendix Chapter A1.

b. Seismic evaluation and design of the wall anchorage system in reinforced concrete and reinforced masonry wall buildings with flexible

diaphragms in Risk Category I or II are permitted to be based on the procedures specified in IEBC Appendix Chapter A2.

c. Seismic evaluation and design of cripple walls and sill plate anchorage in residential buildings of light-frame wood construction in Risk

Category I or II are permitted to be based on the procedures specified in CEBC Appendix Chapter A3.

d. Seismic evaluation and design of soft, weak, or open-front wall conditions in multi-unit residential buildings of wood construction in Risk

Category I or II are permitted to be based on the procedures specified in CEBC Appendix Chapter A4.

e. Seismic evaluation and design of concrete buildings and concrete with masonry infill buildings in all risk categories are permitted to be

based on the procedures specified in IEBC Appendix Chapter A5.

Those associated with the BSE-1 Earthquake Hazard Level defined in ASCE 41 and the performance level as shown in Table 405.2.3.1. Where ASCE 41 is used, the design spectral response acceleration parameters SXS and SX1 shall not be taken less than seventy-five percent of the respective design spectral response acceleration parameters SDS and SD1 defined by the California Building Code and its reference standards.

(Ord. 5564 § 2 (part), 2022)