Diamond Bar Municipal Code Div. 12 Residential Code

Footnotes:

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Editor's note— Ord. No. 04(2019), § B.7., adopted Dec. 3, 2019, repealed the former Div. 12, §§ 15.00.3210—15.00.3230, and enacted a new Div. 12 as set out herein. The former Div. 12 pertained to similar subject matter and derived from Ord. No. 10(2016), § 7, adopted Nov. 15, 2016.

Except as otherwise provided by this title, Sections 102 to 116 of the Administration Code, Section 1207 of Chapter 12, and Appendix J of the 2025 California Building Code (Part 2 of Title 24 of the California Code of Regulations) are hereby adopted and incorporated herein by reference as though fully set forth in this division, and shall be known as Sections R102 to 116 of Chapter 1, Section 1207 of Chapter 12, and Appendix J of the 2025 California Residential Code (Part 2.5 of Title 24 of the California Code of Regulations).

Except as amended by section 15.00.3220, the 2025 California Residential Code (Part 2.5 of Title 24 of the California Code of Regulations), and Appendices H (Patio Covers), J (Existing Buildings and Structures), K (Sound Transmission), and O (Automatic Vehicular Gates) thereto, based on the 2024 International Residential Code published by the International Code Council, is hereby adopted and incorporated herein by reference as though fully set forth in this division and shall constitute the building code of the city. A copy of such code has been deposited in the office of the city clerk and shall be, at all times, maintained by the city clerk for use and examination by the public.

(Ord. No. 04(2019), § B.7., 12-3-19; Ord. No. 03(2022), § 7, 11-15-22; Ord. No. 03(2025), § 7, 11-18-25)

(1) Section R301.1.3.2 of the California Residential Code is amended to read as follows:

R301.1.3.2 Wood frame structures. The building official shall require construction documents to be approved and stamped by a California licensed architect or engineer for all dwellings of wood frame construction more than two stories and basement in height located in Seismic Design Category A, B or C. Notwithstanding other sections, the law establishing these provisions is found in Business and Professions Code sections 5537 and 6737.1.

The building official shall require construction documents to be approved and stamped by a California licensed architect or engineer for all dwellings of wood frame construction more than one story in height or with a basement located in Seismic Design Category D0, D1, or D2.

(2) Sections R309.1 and R309.2 of the California Residential Code are revised by amending the exception to these two Sections to add exception 3 to read as follows:

Exception 3: An automatic residential fire sprinkler system shall not be required for additions or alterations to existing buildings that are not already provided with an automatic residential fire sprinkler system unless the addition or alteration affects more than 90% of an existing structure located within a Very High Fire Hazard Severity Zone. In that instance, modifications to more than 90% of the existing structure shall be considered a new structure and shall require the installation of an automatic residential fire sprinkler system and meet Fire Zone requirements.

(3) Section R337.1.3 of the California Residential Code is amended to restate exemption 5 as follows:

5. Additions to and remodels of buildings originally constructed prior to the applicable application date that do not affect more than 90% of the existing structure. Modifications to more than 90% of the existing structure shall be considered a new structure.

(4) Section R341 is added to the California Residential Code to read as follows:

R341 Sound Transmission Control. Criteria for sound transmission control between dwelling units and outside noise shall be as provided in the California Building Code. Refer to Section 1206 of the California Building Code for criteria where sound transmission applies.

(5) Section R342 is added the California Residential Code to read as follows:

R342 Structural Tests and Inspections. Structural test and inspection requirements which are omitted from the California Residential Code are intended to refer to the California Building Code.

When structural tests and special inspections are required due to the methods of construction the tests and inspections shall be performed and documented as required in Chapter 17 of the California Building Code.

(6) Section R343 is added to the California Residential Code to read as follows:

R343 Pool Barrier Requirements. Pool barrier criteria are not explicitly located within the California Residential Code and are intended to refer to the California Building Code.

Where any body of water over 18" occurs, refer to California Building Code Section 3109 for pool barrier requirements.

(7) Section R403.1.4.1 of the California Residential Code is amended to read as follows:

R403.1.4.1 Foundations on Expansive Soil. Unless otherwise specified by a registered geotechnical engineer, foundation systems within the City of Diamond Bar are considered to be on expansive soil and shall be constructed in a manner that will minimize damage to the structure from movement of the soil. See Building Code Section 1809.4 for requirements.

(8) Section R602.10 of the California Residential Code is amended by the addition of an exception to read as follows:

R602.10 Wall bracing.

EXCEPTION: Construction documents shall be designed in accordance with engineered design by a California licensed architect or engineer per the California Building Code for dwellings of wood frame construction more than one story.

(9) Section R602.10.8, item 1, of the California Residential Code is amended to read as follows:

R602.10.8 Braced wall panel connections.

1. Parallel rafters or roof trusses shall be attached to the top plates of braced wall panels through solid blocking and framing anchors or equal each bay. No gaps or voids from the roof sheathing through the entire connection shall occur.

(Ord. No. 04(2019), § B.7., 12-3-19; Ord. No. 03(2022), § 7, 11-15-22; Ord. No. 02(2025), § 3, 8-5-25; Ord. No. 03(2025), § 7, 11-18-25)

It shall be unlawful for any person, firm, partnership, or corporation to violate any provision, or to fail to comply with any of the requirements, of this division. Any person, firm, partnership, or corporation violating any provision of this division or failing to comply with their requirements shall be deemed guilty of a misdemeanor and upon conviction thereof shall be punished by a fine not exceeding $1,000.00 or by imprisonment not exceeding six months or by both such fine and imprisonment. Each such person, firm, partnership, or corporation shall be deemed guilty of a separate offense for each and every day or any portion thereof during which any violation of any of the provisions of this division or the codes adopted hereby is committed, continued or permitted by such person, firm, partnership, or corporation, and shall be deemed punishable therefore as provided in this division.

(Ord. No. 04(2019), § B.7., 12-3-19; Ord. No. 03(2022), § 7, 11-15-22; Ord. No. 03(2025), § 7, 11-18-25)