James Hardie Class A Fire rated Assembly

James Hardie Siding: A Class A Fire-Rated Solution for Wildfire-Ready Homes

Wildfires are becoming a year-round threat in many parts of the western United States, and homeowners are facing growing pressure from both insurance carriers and building codes to fire-harden their homes. While many people focus on clearing brush or installing fire-resistant roofing, the siding of a home plays a critical role in defending against wildfire. One of the best products on the market for this purpose is James Hardie fiber cement siding, which offers Class A fire resistance and long-term durability without sacrificing aesthetics.

At Colorado Wildfire Defence, we recommend James Hardie products as a key component in a complete home hardening strategy. This article will explore why James Hardie siding is such a strong choice for wildfire zones, how it achieves its Class A fire rating, and why it’s superior to other siding materials.

What Does "Class A Fire Rating" Mean?

A Class A fire rating is the highest rating available for building materials when it comes to fire resistance. To achieve this rating, a material must:

• Withstand direct flame exposure for an extended period

• Resist flame spread

• Limit heat release and ember penetration

• Not contribute to combustion of the structure

In siding applications, a Class A fire rating ensures that the material won’t ignite easily, melt, or allow fire to penetrate into the wall assembly behind it. In wildfire-prone areas, this rating is critical—especially where radiant heat and flying embers are major threats.

What Is James Hardie Siding?

James Hardie siding is made from fiber cement, a mix of cement, sand, cellulose fibers, and proprietary additives. The result is a highly durable, non-combustible material that performs well in extreme climates and resists fire, moisture, pests, and rot.

Common James Hardie products include:

• HardiePlank® Lap Siding

• HardiePanel® Vertical Siding

• HardieShingle® Siding

• HardieTrim® Boards

These products are available in a variety of styles and finishes, including woodgrain textures that mimic traditional wood siding—without the fire risk.

Why Fiber Cement Is Ideal for Wildfire Zones

James Hardie’s fiber cement siding is considered non-combustible by most building codes, and is approved for use in Wildland-Urban Interface (WUI) areas. Here’s why:

✅ Non-Combustible Composition

Unlike vinyl, wood, or engineered wood siding, James Hardie siding does not ignite when exposed to flame or embers. It will not melt, feed the fire, or emit toxic smoke.

✅ Class A Fire Rating (ASTM E84)

James Hardie siding has been tested to the ASTM E84 standard, achieving a Class A flame spread rating of 0. This means it resists flame spread better than most materials on the market.

✅ No Warping or Melting

Vinyl siding can melt at temperatures as low as 160°F—even from radiant heat alone. James Hardie siding maintains its shape and integrity in high heat conditions.

✅ Long Lifespan

Beyond fire resistance, James Hardie siding is extremely durable and resistant to hail, wind, moisture, and UV exposure. It can last 30 to 50 years or more with proper installation and maintenance.

Siding and Wildfire Ignition: The Facts

During wildfires, flying embers are the leading cause of home loss—not the flames themselves. Embers land on or near structures, smolder, and ignite flammable surfaces like wood siding or vinyl. Once the siding burns or melts, fire can quickly enter the wall cavity and spread to the interior.

In fact, according to research from the Insurance Institute for Business and Home Safety (IBHS), homes with fire-resistant siding, vents, and roofs have significantly higher survival rates in wildfire zones.

James Hardie siding acts as a barrier to ember entry and radiant heat, giving firefighters more time and giving homeowners a much better chance of saving their homes.

How It Compares to Other Siding Materials

Siding TypeFire RatingCombustibilityMelting RiskDurabilityAppearanceJames HardieClass ANon-combustibleNo30–50 yearsExcellentWoodPoorCombustibleNo15–30 yearsNatural lookVinylVariesCombustibleYes (low temp)20–30 yearsModerateEngineered WoodModerateCombustibleNo20–40 yearsGoodStuccoClass ANon-combustibleNo50+ yearsVariable

James Hardie combines the fire protection of stucco with the beauty and versatility of wood.

Installation Matters: Fire Resistance Depends on Proper Assembly

One of the most important—and overlooked—parts of achieving a Class A fire rating is installation. Even the best materials can fail if not installed correctly.

At Colorado Wildfire Defence, we don’t just install siding—we build full Class A-rated wall assemblies, using:

• Non-combustible house wraps and sheathing

• Proper spacing and vent screening

• Sealed gaps around windows and doors

• Metal flashing and ember-resistant trim components

We ensure the entire exterior system is designed to resist ignition—not just the surface.

Insurance and Code Benefits

With fire insurance becoming harder to maintain in Colorado’s wildfire zones, using James Hardie siding can offer critical benefits:

• Helps meet insurance requirements for fire-resistant exteriors

• Qualifies for Wildfire Prepared Home and Firewise USA programs

• Complies with WUI building codes in many counties

• Increases home value and resale appeal in high-risk areas

We also provide documentation and inspection reports that can be shared with your insurance carrier to help maintain or lower your premiums.

Real Homes, Real Protection

Across Colorado, we’ve helped dozens of homeowners upgrade to James Hardie siding as part of our wildfire mitigation projects. Many of these homes have gone on to qualify for improved insurance coverage, and some have even survived ember exposure thanks to their hardened exteriors.

We’ve seen firsthand how small vulnerabilities—like flammable siding, unsealed joints, or plastic vents—can be the difference between a home that survives and one that doesn't. That’s why James Hardie siding is a core part of what we do.

Is James Hardie Siding Right for Your Home?

If you live in a wildfire-prone area and your home has wood, vinyl, or aging composite siding, it may be time to upgrade. James Hardie fiber cement siding offers unmatched protection, durability, and design flexibility—and it plays a key role in helping homes stand up to fire.

At Colorado Wildfire Defence, we specialize in full-home fire hardening, including Class A-rated siding, roofing, windows, and vents. We don’t just install products—we assess your entire exterior and provide a plan for real wildfire resistance.

Final Thoughts

Wildfires are no longer a distant threat—they’re a reality for thousands of Colorado homeowners. Upgrading to James Hardie siding is a proactive step that protects your property, satisfies insurance requirements, and adds lasting value.

Schedule your wildfire home assessment today and find out how James Hardie siding can help fire-harden your home—without compromising on style.