If you own a home along Colorado’s Front Range, you’ve always known wildfire was a real risk. What changed in 2026 is that it became a building code issue. Jefferson County’s Wildfire Resiliency Code went into effect on July 1, 2026. And for homeowners in the county’s Wildland Urban Interface zones, it means exterior siding is no longer just an aesthetic decision.
When you replace your siding, you may now be required to use fire-resistant materials that meet specific structure-hardening standards. Here’s what you need to know, and why the timing matters if you’ve been thinking about new siding.
Table of Contents:
- What Is the Jefferson County Wildfire Resiliency Code?
- Why Your Siding Material Is Now a Fire Mitigation Decision
- How James Hardie Satisfies the New Code
- The Insurance Factor: Colorado HB25-1182
- What About Decks?
- Need A Siding Replacement Now?
What Is the Jefferson County Wildfire Resiliency Code?
Colorado adopted a statewide Wildfire Resiliency Code in 2025. Jefferson County went further — developing its own code that’s stricter than the state minimum — which the Board of County Commissioners approved in March 2026 and began enforcing on July 1, 2026.
The code applies to homes in mapped Wildland Urban Interface (WUI) zones — the areas where developed neighborhoods meet fire-prone wildlands. Most communities in Jefferson County’s foothills corridor fall within WUI designation, including Golden, Morrison, Evergreen, Lakewood, and surrounding communities.
The key point for homeowners: The code is not retroactive. If you’re living in your existing home and not undertaking a permitted exterior renovation, you’re not required to make immediate changes. But when you pull a permit for siding replacement, deck work, or other covered exterior projects — the code applies.
Structure hardening requirements under the code include:
- Siding and exterior cladding materials that limit fire ignition
- Deck surfaces constructed of noncombustible or fire-resistant materials
- Roofing classified as Class A
- Ventilation openings that prevent ember intrusion
Why Your Siding Material Is Now a Fire Mitigation Decision
Most homeowners think about wildfire preparation in terms of defensible space — clearing vegetation, managing brush, keeping wood piles away from the structure. What’s newer — and what the 2026 code formalizes — is the recognition that the exterior cladding on your home is itself a fire mitigation decision.
Here’s the practical reality: during a wildfire, your home’s exterior is the first thing embers contact. Vinyl siding melts and burns. Wood siding ignites. A siding material that limits fire ignition — even for a short window of time — can mean the difference between a home that survives an ember shower and one that doesn’t.
Jefferson County’s wildfire risk is 98% above the national county average. The Front Range foothills communities that Lasting Exteriors serves — Lakewood, Golden, Arvada, Morrison, Evergreen, and surrounding areas — are not theoretical risk zones. They’re real ones.
How James Hardie Satisfies the New Code
James Hardie fiber cement siding carries a Class A fire rating under ASTM E84 testing — the highest classification available for exterior cladding. It is explicitly recognized by the Jefferson County Wildfire Resiliency Code as a compliant Class 2 structure-hardening material for WUI Intermix zones.
James Hardie is also the product Lasting Exteriors specializes in. If you’re in a WUI zone and need siding that satisfies the new code requirements, you’re working with a contractor who installs this material exclusively — not as one option among many.
Unlike vinyl siding, fiber cement is made from cement, sand, and cellulose fibers. It doesn’t burn. It doesn’t melt. And it doesn’t contribute to fire spread the way combustible materials do.
Beyond fire performance, James Hardie is engineered for Colorado’s full weather profile — not just wildfire risk:
- Hail resistance — handles Colorado’s Class 4 hail events without the cracking and impact damage that vinyl sustains
- Freeze-thaw durability — the HardieZone system is specifically engineered for Colorado’s temperature swings
- UV resistance — ColorPlus Technology maintains color integrity at Colorado’s high-altitude UV exposure without the fading that affects other materials
- 30-year non-prorated warranty — on siding and finish when installed by a certified contractor
The Insurance Factor: Colorado HB25-1182
There’s a financial dimension to this conversation that most homeowners haven’t heard yet.
Colorado House Bill 25-1182, which took effect January 1, 2026, fundamentally changed how insurers must handle wildfire risk in the state. For the first time, Colorado insurers are legally required to:
- Disclose their wildfire risk model and your property’s risk score
- Incorporate your structure-hardening efforts into their pricing models
- Provide a pathway for premium reductions when you install fire-resistant materials
Meaning installing James Hardie fiber cement siding on a Front Range home can be a documented mitigation step that your insurer must now factor into your premium. They’re fire-resistant siding, and extremely durable for Colorado’s weather. For homeowners who’ve watched Colorado insurance costs climb in recent years, that’s a meaningful financial consideration alongside the protection itself.
What About Decks?
This is the detail that surprises most homeowners: the Jefferson County Wildfire Resiliency Code also covers deck surfaces.
Wood decks are one of the most common ignition points during wildfire events. Embers collect in board gaps. The under-deck space sustains ignition. Under the new code, deck surfaces in WUI Intermix zones must be constructed of noncombustible or fire-resistant materials — which means a standard wood deck no longer meets code for permitted deck projects in covered areas.
Lasting Exteriors installs TimberTech composite decking — a fire-resistant system that satisfies the WUI code requirements and delivers the outdoor living space Colorado homeowners want, without the annual maintenance burden or fire vulnerability of wood. If a siding replacement and deck project are both on your list, addressing them together under one permitted scope is the most efficient path.
Need A Siding Replacement Now?
The new code means that when you eventually do replace your siding, fire-resistant materials may be required. Doing it proactively — rather than reactively after the next hail storm or when the siding fails — gives you the most control over timing, product selection, and budget.
Lasting Exteriors has completed over 2,600 exterior projects across the Denver metro and Front Range communities. Jason and the team specialize in James Hardie fiber cement installation, and every project is backed by a lifetime workmanship warranty, as long as you own your home.
If your siding is aging, damaged from a recent hail event, or simply the original vinyl from when the home was built, 2026 is a particularly meaningful time to make the change.
When you’re ready for a siding replacement…
Request your free siding estimate from Lasting Exteriors →
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