Insights
As wildfires increase in frequency and severity, the construction industry is turning to advanced fire-resistant building techniques and materials to create “fire-hardened” homes that can withstand extreme heat, direct flames, and wind-driven embers. While California’s Wildland-Urban Interface (WUI) codes (CBC Chapter 7A) set minimum fire-resistance standards, advancements in materials, construction techniques, and technologies now allow builders and homeowners to exceed these requirements for superior protection.
This report explores:
To reduce wildfire risk, Class A fire-resistant materials should be used for roofing, siding, and decking. Limiting combustible materials in walls, insulation, and decks further prevents ignition. Eliminating ember entry points, such as vents, eaves, and windows, is crucial. Sealed vents, fire-rated windows, and noncombustible soffits provide critical protection.
Fire suppression and early detection technologies, such as automated sprinklers, ember-resistant vents, and AI-powered wildfire detection, add an extra layer of defense. Proper site planning—maintaining a five-foot noncombustible perimeter and using fire-resistant landscaping—reduces the risk of direct flame contact. By combining fire-resistant construction, ember-proofing, and suppression technology, homes can be significantly more resilient to wildfire threats.
Residences or structures located in a Fire Hazard Severity Zone, as per CalFire Fire Hazard Severity Zone Maps and the California Fire Code, must have 100 feet of defensible open space around all residences and 10 feet of defensible space along each side of driveways and roads. Additional driveway and fire hydrant requirements may apply to new or replacement structures, depending on the driveway length and dwelling size. Some County Fire Codes may impose further requirements.
Replacement structures must be reconstructed in compliance with the requirements for Moderate or Severe Fire Severity Zones (HFSZ or SFSZ) and adhere to the wildfire protection provisions outlined in the California Residential Code (CRC) R337 and the California Building Code (CBC), including:
The following components require special attention or alternative materials to meet fire-resistant standards.
The roof is one of the most vulnerable areas, and Class A roofing materials provide the highest level of fire resistance.
Good practices for fire-hardened roofing include installing fire-hardened underlayment to provide additional protection beneath the roof covering. Additionally, using sealed edges and metal flashing helps prevent ember intrusion, reducing the risk of ignition during a wildfire. Use of a Class A roofing underlayment is also required if the roof decking is not fire-retardant treated wood.
Noncombustible or ignition-resistant siding materials are essential for reducing fire spread and radiant heat ignition per ASTM E2707.
Fire-rated sheathing (5/8-inch Type X gypsum) should be used behind the siding for additional resistance, and it is important to ensure the presence of tight joints and noncombustible backing to prevent embers from entering wall cavities.
Openings in a home’s envelope—windows, doors, and attic vents—are critical weak points in fire defense.
Installing metal corrosion-resistant mesh screens (1/16-inch or 1/8-inch mesh) helps block embers and reduce the risk of ignition. Additionally, limiting the number and size of windows on fire-exposed sides of the home helps minimize vulnerability.
Fire-resistant insulation and decking reduce fuel sources and slow fire spread.
For enhanced fire resistance, elevated decks and porches should be constructed using concrete or metal whenever possible to minimize ignition risk. Maintaining a non-combustible five-foot perimeter around the structure is also essential to reduce exposure to embers and direct flames.
Recent advancements in nanotechnology have led to the development of fireproof coatings that significantly improve the heat resistance of traditional building materials. These coatings can be applied to wood, metal, and composite materials to prevent ignition and slow flame spread.
Additionally, self-healing coatings help repair microcracks caused by extreme heat, preserving their protective properties over time. Some coatings also incorporate insulative ceramic particles (ICP) technology, which reduces heat absorption and creates a thermal barrier, further enhancing fire resistance. These innovations offer a promising solution for improving residential structures' durability and wildfire resilience.
Important Note: According to California building codes, the use of paint, coatings, stains, or similar treatments is not an approved method of fire protection.
One of the most effective strategies for constructing fire-resistant homes is replacing traditional wood framing with noncombustible, insulated mass walls. Insulated concrete forms (ICFs) are a cutting-edge wall system that utilizes interlocking foam blocks filled with steel-reinforced concrete to create a monolithic, highly insulated structure.
ICF walls have demonstrated exceptional fire resistance; however, to ensure maximum protection, all exterior cladding must be ignition-resistant or noncombustible.
Prefabricated fire-resistant panels enhance wildfire resilience by offering noncombustible, high-performance materials while streamlining construction. These panels, which include composite cores for walls and roofing, arrive pre-finished and fire-rated, reducing the need for extensive on-site labor. To ensure maximum protection, materials should comply with WUI fire-resistance standards, and fire-resistant adhesives and fasteners should be used to maintain durability and integrity under extreme heat exposure.
Artificial intelligence is revolutionizing wildfire detection by enabling AI-driven camera networks to identify fires before they are visible to the human eye. These systems continuously monitor landscapes, detecting smoke and heat signatures in real-time, allowing for rapid response. Additionally, satellite-based AI fire prediction models analyze environmental conditions to identify ignition risks in advance, helping communities prepare for potential wildfire threats before they escalate.
Smart fire suppression technologies are enhancing home protection by automating fire defense measures. Smart sprinkler systems activate when heat sensors detect nearby wildfires, soaking the home and surrounding vegetation to prevent ignition. Ember-resistant vents block airborne embers from entering attics and crawlspaces, while AI-controlled fire shutters automatically seal windows and doors when high temperatures are detected. Together, these systems provide an advanced, proactive defense against wildfires, reducing the risk of structural ignition.
Malibu’s “miracle mansion” demonstrates how fire-resistant materials, innovative construction techniques, and emerging technologies can significantly enhance a home’s wildfire survivability. By integrating noncombustible materials, ember-proofing, and smart suppression systems, knowledgeable experts can design homes in fire-prone areas to withstand extreme fire events and improve long-term resilience. Additionally, consulting experts with multidisciplinary expertise in wildfire risk, construction consulting, and code compliance, can help greatly when building smarter, safer, and more resilient structures in high-risk environments.
We would like to thank Travis Sommerfeld, Adam Norman, and Erik Fritzberg, RA, CBO, CPHC, CFM, for their insight and experience, which greatly assisted this research.
Travis Sommerfeld is a Senior Vice President in J.S. Held’s Building Consulting practice, overseeing a team of professionals across multiple regions. With over a decade of experience in construction consulting, he has managed complex projects across residential, commercial, industrial, and institutional sectors, specializing in damage quantification, cost estimating, and large-loss assessments. Travis has provided expert consulting on high-net-worth properties, high-rises, hospitals, and university campuses. He has shared his industry knowledge through speaking engagements on building materials, construction scheduling, and restoration technologies.
Travis can be reached at [email protected] or +1 724 815 5501
Adam Norman is Vice President of Operations – Client Success within J.S. Held’s Building Consulting practice. In this role, Adam is responsible for enhancing quality assurance, operational efficiency, and client experience across insurance-facing practices. He plays a key role in developing and implementing technology-driven, expert-based services that improve service delivery and streamline complex processes. His extensive experience includes leading large-scale, KPI-driven teams in the insurance and claims industry and earning meritorious promotions during his military service. Adam’s ability to build strong client relationships, drive operational improvements, and lead complex projects makes him an integral part of J.S. Held’s ongoing innovation and success.
Adam can be reached at [email protected] or +1 857 767 2125
Erik Fritzberg is a Senior Architect with extensive licensure in J.S. Held’s Forensic Architecture and Engineering practice and a professional mitigation, construction, and building code expert specializing in the application of code-required upgrades as they apply to existing buildings. Erik also assists with all aspects of building shell and assembly design and specification. Erik’s experience with numerous institutional, commercial, educational, industrial, and residential projects of various construction types and complexities, both new and existing, provides him with a broad range of expertise to assist owners and clients.
Erik can be reached at [email protected] or +1 412 293 3756
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