Embracing Safety: Washington WUI Code Update 2023

May 31, 2023
Blog cover photo featuring the Graystone timber floor plan in the snow built by Lexar Homes of Spokane

Embracing Safety: Washington WUI Code Update 2023


Washington State has made a significant stride in promoting safety and fire resilience in the Wildland-Urban Interface (WUI) areas with the recent adoption of the 2018 International Wildland Urban Interface Code (IWUIC).


This Washington WUI Code Update 2023 underscores the state’s commitment to minimizing fire risks and safeguarding communities located in the WUI zones. Check out the Washington state wildland-urban interface map for a comprehensive look at the state overall and explore the WUI story map for more detailed interpretations of the map and how it was set up. Below are some highlights of the new code being implemented on July 1, 2023.

Roof Coverings

One of the most notable updates in the Washington WUI Code pertains to roof coverings. It is now mandatory that roofs have a Class A rating, denoting the highest level of fire resistance. This rigorous standard is enforced not only for new construction homes, but also for existing structures. If a roof covering is replaced by 50% or more within a year, it must meet the standards applicable for new construction. Similar rules are enforced for additions to existing buildings.

Exterior Walls

Further, the new guidelines also address the construction of exterior walls. Washington WUI Code Update 2023 mandates the use of materials that satisfy certain fire-resistance standards. This can be achieved through multiple construction methods, including one-hour fire-resistance rated construction or use of noncombustible materials. The fire-resistant materials should extend from the foundation’s top to the underside of the roof sheathing, enhancing the structure’s overall resilience against wildfires.

Accessory Structures

The updated code also sets stringent regulations for the construction of unenclosed accessory structures like decks. These structures, attached to buildings, are required to be constructed with materials meeting the fire-resistance standards. There are, however, exceptions for specific structures built with materials of a minimum size and screened underneath to prevent ember entry.

Type of Property

Driveways are another significant consideration in the Washington WUI Code Update 2023. The updated code requires driveways where any part of an exterior wall of the first story of the building is more than 150 feet from a fire apparatus access road. Longer driveways must be equipped with turnarounds and turnouts, ensuring smooth access for emergency vehicles.

Local Adoption

Finally, it’s essential to note that all counties, cities, and towns have the freedom to adopt the IWUIC or any part thereof. Amendments to the code can be made, provided they don’t exceed the minimum performance standards and requirements in the published model code.

Final Thoughts

The Washington WUI Code Update 2023 illustrates a clear, practical approach to reducing fire risks in wildland-urban interface zones. By adopting and enforcing these updated standards, Washington State is taking a proactive role in protecting its communities and natural landscapes from the ever-present threat of wildfires. The move is a testament to Washington’s dedication to ensuring the safety and well-being of its residents and environment. At Lexar Homes, we pride ourselves on being a forward-thinking, innovative custom home building company. Staying ahead of the curve is a key part of our commitment to our customers, and that includes understanding and implementing the latest safety standards like the Washington state WUI Code. Our knowledgeable team is well-versed in these new codes and is ready to ensure your new home not only meets but exceeds these standards. When you choose to build with Lexar Homes, you’re choosing a partner dedicated to providing you with a safe, secure, and compliant home that’s prepared for the future. Find a location near you today and contact us!