Council examines supplemental sound‑separation construction standards for duplexes

Staff presented language to the council that would supplement the city’s construction standards to require specific stud-wall assemblies — staggered studs or double-stud walls — intended to increase sound transmission class (STC) and reduce noise between attached units. The staff presentation noted the proposed supplement is intended to be more stringent than the International Residential Code (IRC) 2018 and not to supplant essential IRC requirements.

Council members pressed for technical detail. One council member asked whether the package specifically required insulation or other sound‑deadening materials; staff replied that the assembly package would include insulation and sheetrock and that staff would verify and clarify the exact installation requirements. Staff also said the code language would be revised to explicitly state it supplements, rather than replaces, existing code where those codes remain applicable.

The council appeared inclined to move forward with careful revisions but asked staff to verify the technical claims and return with more precise language that preserves or increases sound attenuation without inadvertently reducing other safety or fire-rating standards. The council discussed inspection capacity and the need for the new building inspector (starting July 1) to be able to enforce any new requirements.