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Earlier editions: 20222019

Appendix BG — SOUND TRANSMISSION

BG103 Structural-Borne Sound — 2025 California Residential Code

California Residential Code (Title 24, Part 2.5) · 2025 edition · updated 2026-10-19 · California

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Italicized text is a California amendment to the model code, as printed in the official publication.

Cite as: 2025 California Residential Code (Title 24, Part 2.5) § BG103 · Effective January 1, 2026 · Official source: Building Standards Commission

BG103.1 General.

Floor/ceiling assemblies between dwelling units, or between a dwelling unit and a public or service area within a structure, shall have an impact insulation class (IIC) rating of not less than 45 when tested in accordance with ASTM E492 or a Normalized Impact Sound Rating (NISR) of 42 where tested in accordance with ASTM E1007.

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▸Contents — California Residential Code (Title 24, Part 2.5)
California Residential Code (Title 24, Part 2.5)

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