Building for Fire Resilience: How EXACOR® Panels Support WUI Compliance
5 Min Read July 1, 2025
The Wildland-Urban Interface (WUI) presents unique challenges for construction professionals, requiring materials that can withstand fire conditions. As one of the newest additions to Huber Engineered Woods' product lines, EXACOR® MgO sheathing panels offer builders a fire-resistant alternative to traditional building materials. With its impressive fire performance, EXACOR sheathing can be well-suited for projects in WUI zones, where meeting fire-resistance standards is critical.
Understanding the Wildland-Urban Interface (WUI)
What is the Wildland-Urban Interface, and why does it matter for construction?
The WUI is where human development meets undeveloped wildland areas. This happens often in places with abundant forest land, like the states of Colorado, Montana, California, and Texas. These regions are highly susceptible to wildfires due to their proximity to flammable vegetation. As a result, stricter building codes are in place to enhance fire resistance and protect structures from ember attacks, direct flame exposure, and heat damage.
How do I know if my project is in a WUI-designated area?
Local building departments and state agencies maintain maps of WUI-designated zones. In some states, like California, the California Building Code (CBC) specifically outlines WUI compliance requirements. Reach out to your local code authority for your specific requirements.
What are the key fire-resistance requirements for WUI construction?
Many states use the standards developed by the International Wildland Urban Interface Council (IWUIC) to set the requirements for their area. For general guidance, WUI-compliant construction typically requires:
- Fire-resistant exterior walls, roofs, and decks
- Ember-resistant vents and openings
- Non-combustible or ignition-resistant materials
- Properly sealed gaps to prevent ember intrusion
Builders should consult with their local authority having jurisdiction to confirm specific requirements.
EXACOR Fire Ratings & WUI Compliance
Is EXACOR sheathing approved for use in WUI zones?
Yes; EXACOR panels are fire-resistant, making them a strong option for use in WUI-compliant assemblies. Check out our Tech Tip on EXACOR Wall Sheathing in Wildland Urban Interfaces to see how EXACOR panels can help comply with these requirements. Many state and local codes that address WUI zones use the requirements set forth in Chapter 5 of the model code, IWUIC; however, builders should confirm compliance with specific local codes and requirements before installation.
You can find all fire resistance-rated assemblies and other product information for EXACOR sheathing in our technical library as well as the EXACOR Fire & Sound Handbook.
How does EXACOR perform in fire resistance tests compared to other materials?
EXACOR panels are rigorously tested for fire performance and outperform many traditional materials in flame spread and fire endurance tests. See how EXACOR can be tested for fire assemblies here. You can also find additional testing here.
What fire ratings does EXACOR have, and how does that help with WUI compliance?
EXACOR panels have achieved Class A flame spread ratings and have been tested for use in one- and two-hour fire-rated assemblies, which may be suitable for fire-resistant construction in WUI zones. It is recommended to confirm area-specific code requirements before installation.
How do EXACOR panels compare to fire-retardant-treated plywood and coated oriented strand board for use in WUI applications?
Unlike wood-based products, EXACOR panels resist exposure to moisture, reducing the risk of swelling and delamination in harsh environments.
Can EXACOR panels be used as part of a fire-resistant assembly in a WUI project?
EXACOR panels integrate into various fire-resistance rated wall assemblies that may be suitable for WUI compliance. Always check your local code requirements before installation.
Does EXACOR provide additional benefits beyond fire resistance in WUI construction?
Beyond fire resistance, EXACOR provides:
- Moisture resistance to reduce material deterioration
- Strength and durability for high-performance construction
- Sound-dampening qualities for improved acoustic performance
Construction & Installation Best Practices
What are the best practices for installing EXACOR?
Follow manufacturer guidelines and requirements for installation, including panel fastening.
Check out the EXACOR Wall Sheathing Installation Manual for more install-specific information.
Are special fasteners required when using EXACOR?
EXACOR wall sheathing requires the use of hot-dipped-galvanized or better fasteners in all applications, but building professionals should verify compliance with local WUI codes and manufacturer recommendations for their specific project.
Refer to our EXACOR Fire & Sound Assemblies Handbook for more information.
Code & Certification
What fire testing standards do EXACOR panels meet?
EXACOR panels have undergone extensive fire testing to meet standards. For the specific standards met, check out our tech tip.
How do I verify that EXACOR sheathing meets my local WUI building code requirements?
Builders should check local building codes and confirm with the applicable authority having jurisdiction. For reference, EXACOR’s technical documents and fire test reports can be found here.
Are there specific jurisdictions where EXACOR sheathing has been pre-approved for WUI construction?
Approval varies by region, so it’s essential to consult local authorities and code officials for pre-approved materials lists.
Here is an example of a WUI approved product list from the city of Austin, TX.
Where can I find test reports or documentation on EXACOR’s fire performance?
Documentation can be accessed through Huber Engineered Woods’ technical library or by contacting a local sales representative or supplier.
As wildfire risks continue to shape building codes, having the right materials is essential. EXACOR® MgO panels provide builders with a fire-resistant, durable, and easy-to-install solution to support compliance with WUI requirements.
For more information on EXACOR and its fire-resistance rated assemblies, visit Huber Wood’s site or find the nearest supplier near you.