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Building for wildfire resilience: Solutions for WUI areas

Download the WUI guide

Wildfires continue to be a growing threat across North America, causing widespread devastation to homes, businesses, and communities. The Wildland-Urban Interface (WUI), where communities meet wildland vegetation, faces increasing wildfire exposure as climate change drives longer and more intense fire seasons. According to the U.S. Forest Service, the number of houses within wildfire perimeters has doubled since the 1990s.

To reduce wildfire risks, many jurisdictions have implemented stricter building codes to enhance fire resilience. In the U.S. and Canada, the International Wildland-Urban Interface Code (IWUIC) and the National Guide for Wildland-Urban Interface Fires establish fire safety standards, emphasizing home-hardening, fire-resistant landscaping, and community planning to prevent ignition and fire spread.

Understanding WUI building codes

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Many local and state jurisdictions adapt WUI codes to address their specific wildfire risks and environmental conditions.

While the International Wildland-Urban Interface Code (IWUIC) serves as a model framework in the U.S., individual states and municipalities modify its provisions to reflect regional fire hazards, climate conditions, and available resources.

Similarly, in Canada, the National Guide for Wildland-Urban Interface Fires provides best practices for reducing ignition risks, though adoption varies by province and territory.

Key elements of WUI codes focus on reducing a structure's vulnerability to embers, radiant heat, and direct flame contact. Requirements typically address:

  • Defensible space – Guidelines for vegetation management to minimize fuel sources near structures
  • Building materials – Emphasis on non-combustible or ignition-resistant materials for roofs, walls, exterior finishes, decks, stairs, and fences
  • Ventilation protection – Measures to prevent embers from entering attics, crawl spaces, and other openings

For a comprehensive resource on fire-resistant construction, download our technical bulletin, Building with ROCKWOOL Stone Wool Insulation in Wildfire-Prone Areas. This document provides insights into WUI codes, fire-resilient building strategies, and a set of construction details designed to enhance fire protection.  

WUI building codes across North America

These are examples of existing WUI codes and guides:

Fire-resistant construction: Solutions for WUI zones

Our new technical bulletin provides essential guidance for architects, builders, and homeowners in WUI zones. This comprehensive resource delivers:

  • Detailed guidance on using stone wool insulation to enhance fire resistance
  • U.S. code provisions and Canadian guidelines for wildfire risk mitigation
  • Sample construction details for building in WUI areas
  • Practical solutions and best practices for resilient building
  • Appendices with a code compliance matrix

Whether you're designing a new home, retrofitting an existing structure in a wildfire zone, or looking to improve the fire resilience of your home, this bulletin serves as your go-to reference for safer, code-aligned construction.

Download the technical bulletin
Burnt hillside with smoking homes in Colorado Springs stock photo - wildfires and forest fires - wildland urban interface (WUI) zones

WUI map of the United States

US WUI Map 2020WUI map of Canada

Canada WUI Map

Building with ROCKWOOL in wildfire-prone areas

The State Fire Marshal's Building Materials Listing (BML) Program was created to ensure fire alarm systems and devices were approved before being sold in California and has since expanded to include materials like roof coverings and wall assemblies. Products must undergo rigorous testing by SFM-accredited labs to be listed. The BML Program is a vital resource for professionals ensuring fire and life safety compliance statewide.

ROCKWOOL has several stone wool insulation products listed—the only thermal insulation for exterior walls and roofs currently in the program. These products are recognized as compliant with the California Building Codes. The listings reflect ROCKWOOL's commitment to delivering high-performance insulation solutions that contribute to safer, more resilient buildings.

Explore the official listings & product page for each ROCKWOOL product below:

Balancing energy efficiency and fire safety

Increasingly stringent energy codes in regions like California can create challenges when trying to also meet fire safety requirements. While traditional approaches often pit these priorities against each other, ROCKWOOL's stone wool solutions offer a path to achieving both without compromise.

Naturally noncombustible, stone wool offers exceptional fire resilience, withstanding temperatures over 1000°C (1832°F). In addition to its fire performance, Comfortboard® enhances moisture management through its vapor-permeable and hydrophobic properties, supporting both energy efficiency and building durability.

Read the California House Case Study
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Technical services

Need expert guidance on your WUI project?

Our Technical Services team is here to help you navigate WUI code requirements, choose the right stone wool products, and integrate tested fire-resistant assemblies into your project. Whether you're specifying for a new custom home or retrofitting in a high-risk zone, we're ready to support you with expert guidance and practical resources.

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