The bill aims to reduce embodied carbon emissions in buildings and building materials in Washington State by establishing new standards and requirements for construction projects. It mandates the state building code council to adopt rules that will apply to all new constructions, additions, and renovations of buildings over 50,000 square feet, ensuring they meet specific embodied carbon emissions reductions. The bill outlines that projects maintaining at least 45% of an existing structure will comply with these requirements, and it introduces a framework for calculating embodied carbon emissions based on various metrics. Additionally, it requires that at least 90% of covered products used in building projects meet established carbon emissions goals, with compliance verified by a licensed design professional.

Furthermore, the bill includes provisions for whole building life-cycle assessments as an alternative compliance pathway, ensuring that projects can demonstrate reduced emissions compared to a reference building. It establishes a public database for tracking emissions reductions data and mandates the creation of educational resources to support implementation. The state building code council is tasked with convening a technical advisory group to recommend modifications to the international building code regarding these standards. The ultimate goal is to achieve a 30% reduction in embodied carbon emissions by the 2030 state building code, with incremental progress reports required every three years.