SENATE BILL REPORT
SB 5552
As Reported by Senate Committee On:
Local Government, February 20, 2025
Title: An act relating to the creation of building codes for kit homes.
Brief Description: Concerning the creation of building codes for kit homes.
Sponsors: Senators Wilson, J., Shewmake, Fortunato, Nobles, Braun, Short, Gildon, Christian, Chapman, Holy, McCune, Warnick, Goehner, Dozier, Wilson, C., Slatter, Cortes, Liias, Frame, Krishnadasan and Ramos.
Brief History:
Committee Activity: Local Government: 2/06/25, 2/20/25 [DPS].
Brief Summary of First Substitute Bill
  • Requires the State Building Code Council to perform rulemaking applicable to kit homes by December 31, 2025.
SENATE COMMITTEE ON LOCAL GOVERNMENT
Majority Report: That Substitute Senate Bill No. 5552 be substituted therefor, and the substitute bill do pass.
Signed by Senators Salomon, Chair; Lovelett, Vice Chair; Torres, Ranking Member; Bateman and Goehner.
Staff: Rohan Bhattacharjee (786-7534)
Background:

The State Building Code. The State Building Code (Code) establishes minimum performance standards and requirements for construction and construction materials in the state, consistent with accepted standards of engineering, fire, and life safety. The Code comprises a number of model codes and standards, developed and published by international and national organizations, which are adopted by reference in the State Building Code Act (Act). Model codes and standards adopted in the Act include the International Building Code, International Residential Code, the International Mechanical Code, the International Fire Code, and the Uniform Plumbing Code Standards. The State Building Code Council (SBCC) is responsible for adopting, amending, and maintaining the model codes and standards adopted by reference in the Act.

 

Kit Homes. Kit homes, also known as mill-cut houses, pre-cut houses, mail order homes, or catalog homes, are a type of prefabricated housing. These homes are constructed from a series of prefabricated components which are assembled on site. Kit homes typically do not use materials such as brick, concrete, or masonry. 
Summary of Bill (First Substitute):

SBCC is instructed to perform rulemaking on the Codes applicable to kit homes by December 31, 2025.

 

SBCC may update the Codes applicable to kit homes.

 

Kit homes are defined as any structures intended for residential use comprised of prefabricated walls, floors, and roofs which are assembled on-site and are 800 square feet or smaller in size.
EFFECT OF CHANGES MADE BY LOCAL GOVERNMENT COMMITTEE (First Substitute):
  • Removes the $150 per square foot monetary threshold on rulemaking and the emergency clause.
Appropriation: None.
Fiscal Note: Available.
Creates Committee/Commission/Task Force that includes Legislative members: No.
Effective Date: Ninety days after adjournment of session in which bill is passed.
Staff Summary of Public Testimony on Original Bill:

The committee recommended a different version of the bill than what was heard.  PRO: This bill is a solution to the housing crisis. Kit homes are simple and can potentially be used as accessory dwelling units.The housing crisis deserves urgent solutions, with a projected shortfall of one million homes over 20 years.

 

CON: The bill's definition of kit homes lacks specificity, creating ambiguity about materials and components. The bill's cost cap of $150 per square foot is concerning, which could undermine building safety and health codes. The State Building Code Council’s role in ensuring safe and enforceable regulations is emphasized.

 

OTHER: There are challenges in ensuring long-term compliance with safety standards, particularly for kit homes manufactured out of state. Inspectors typically check homes once after construction, making it difficult to ensure compliance over decades. Clarity is necessary on cost control and long-term safety enforcement while recognizing the potential of kit homes to address housing needs.
Persons Testifying:

PRO: Senator Jeff Wilson, Prime Sponsor.

CON: Tammie Sueirro, AIAWA (American Institute of Architects WA Council).
OTHER: Tim Woodard, Washington Assn. of Building Officials (WABO).
Persons Signed In To Testify But Not Testifying: No one.