OLYMPIA, WA — A new Washington state law aimed at expanding affordable housing options will make it easier to build small “kit homes” and backyard units across the state. Gov. Bob Ferguson signed Engrossed Substitute Senate Bill 5552 into law, following four years of work by Sen. Jeff Wilson. The measure directs the Washington State Building Code Council to develop rules specifically for kit homes under 800 square feet. Supporters say the legislation is intended to help address Washington’s housing shortage by reducing costs and simplifying the construction process for smaller homes. Wilson said standardized kit-home designs could allow plans to be approved once at the state level rather than requiring separate design reviews for each project. Kit homes typically include precut lumber delivered as a package that can be assembled on site. Modern versions often use prefabricated wall and roof panels to speed construction, and start at less than $10,000.