Committee hears bill directing state building code council to adopt standards for kit homes

Senate Bill 5552 would require the State Building Code Council to conduct rulemaking and adopt building-code provisions specific to “kit homes,” defined in the bill as residential structures of 800 square feet or smaller composed of prefabricated walls, floors and roofs intended to be assembled on site.

Kellen Wright, committee staff, told the committee: “The bill before you is senate bill 5 5 5 2, an act relating to the creation of building codes for kit homes.” The bill would require the council to complete rulemaking on portions of the code applicable to kit homes by the end of the year specified in the bill.

Sen. Jeff Wilson, sponsor, said the proposal is meant to add an additional housing option to respond to the state’s housing shortages. “Kit homes have been around,” Wilson said, noting historical catalog homes and describing kit homes as “preassembled and delivered as a kit” that could serve as primary residences or other housing uses.

Committee members asked how kit homes are currently regulated. Wilson said existing statutes leave kit homes “in limbo” and that while “factory assembled structures” are already defined in code, a clear kit-home definition and uniform standards do not yet exist.

Representatives from the State Building Code Council and Washington Association of Building Officials testified they do not oppose the policy goal but urged more time for rulemaking and clearer draft language. Dustin Kurb, managing director for the State Building Code Council, said the council’s normal three-year cycle and current staffing pressures make the bill’s proposed adoption date difficult to meet and recommended folding kit-home provisions into the regular code cycle. “The adoption date of 12/31/2025 necessitates the SBCC conduct rulemaking outside of its normal cycle,” Kurb said, recommending inclusion in the 2024 code cycle instead so code changes would take effect with the next regular update.

Tim Woodward of the Washington Association of Building Officials said the association appreciated the bill directing the council to do rulemaking rather than legislating technical code text, but also noted the workload burden on local building officials if the rulemaking is forced outside normal cycles.

No formal action was taken on the bill during this hearing. Committee staff and witnesses said technical language — for example clarifying which code provisions would or would not apply and whether federal accessibility requirements remain in force — should be refined before the council begins rulemaking.

Supporters said the bill’s intent is to give local permitting authorities a consistent framework for permitting new prefabricated housing types; critics and code officials urged adjustments to the bill’s schedule and wording to allow a robust public-rulemaking process and to avoid unintended exemptions from life-safety or accessibility requirements.