Wildfire Resilience · Colorado WUI Roofing
Wildfire-Ready
Roofing for Colorado Homes.
Your roof is your home's first line of defense against ember attack. Get it right.
The Colorado Insurance Crisis
This isn't a future risk.
It's happening now.
Insurance carriers are non-renewing homeowners across Colorado's Wildland-Urban Interface at a pace not seen before. The Boulder foothills. Colorado Springs west side. Mountain communities from Estes Park to Durango. Homeowners who have held the same policy for 20 years are receiving non-renewal notices. Those who can find replacement coverage are paying 150–250% more than they were paying in 2022. This is not a temporary market correction. It is a structural repricing of wildfire risk, and it is accelerating.
Colorado responded with legislation. The Colorado Wildfire Resiliency Code, adopted July 1, 2025, is now mandatory for all WUI municipalities as of April 1, 2026. It sets minimum construction standards for new buildings and major renovations in fire-prone zones, including Class A roofing, ember-resistant vents, and defensible space requirements that go beyond previous guidelines. HB 1182 adds a financial incentive layer: homeowners who complete qualifying mitigation work, including Class A roofing and documented defensible space, are entitled to meaningful premium discounts from Colorado carriers. The mitigation credit is mandatory for participating insurers. You have to ask for it, and you have to document the work.
The data on outcomes is significant. Homes with a Class A roof, documented defensible space, and FireWise community certification have approximately three times better odds of insurance approval in non-renewal situations than unprotected homes in the same fire zone. That is not a marketing claim. It is the finding from Colorado Division of Insurance carrier surveys conducted after the 2022 Marshall Fire. The roof is not the only variable, but it is the most visible one, and it is the one carriers and fire mitigation inspectors look at first.
Fire Science
Wildfires don't burn houses.
Embers do.
The research on how homes ignite in wildfires is unambiguous: approximately 90% of homes lost in wildfires are ignited by embers, not by direct flame contact with the structure. Embers (burning fragments of vegetation or building materials) can travel up to a mile ahead of the fire front on wind currents, landing on or inside structures well before the main fire arrives. A home can ignite from ember exposure while the fire front is still a half-mile away.
This has a specific implication for roofing. If your home's ignition comes from ember exposure rather than direct flame, the question changes from “will the fire touch my roof?” to “where will embers land, and what will they find when they get there?”
The three ember intrusion paths on a typical home
Gutters and the roof edge
Gutters accumulate dry organic debris: pine needles, leaves, bark. In an ember shower, this debris becomes fuel at the roofline. Once ignited, flame travels under shingles and into the eave assembly within minutes.
Vents and soffits
Standard attic vents and soffit openings are designed to allow airflow. They allow embers in with the same efficiency. A single ember entering an attic through an unscreened vent can ignite insulation, framing, and stored material with no warning from inside the home.
Gaps at the roof edge and panel terminations
Any opening at the eave line (unsealed panel ribs, gaps behind drip edge, loose or missing closures) is an entry point for wind-driven embers. These gaps are small enough to be overlooked during a standard roofing inspection and consequential enough to determine whether a home survives.
The roof and eave system is the most critical ember defense zone on the entire structure. What you put on the roof matters. How it terminates at the eave matters more than most homeowners and most contractors understand.
Fire Rating Standards
Class A:
What it actually means.
The UL 790 test protocol
UL 790 is the standard test for roofing fire resistance. It evaluates three conditions: severe fire exposure from above (burning brand test), intermittent flame exposure (intermittent flame test), and spreading flame (how far flame travels across the surface under sustained exposure). Class A is the highest performance tier: it must withstand severe fire exposure without igniting, must resist flame spread beyond defined limits, and must not allow fire to penetrate to the underside of the roof deck. Classes B and C are tested under moderate and light exposure, respectively. In Colorado WUI zones, Class A is the only specification that matters.
Material rating vs. assembly rating: a critical distinction
A product's Class A rating is always an assembly rating. The entire system is tested together. A Class A shingle installed over a non-rated or improper underlayment may produce a lower assembly rating than the shingle alone would suggest. This is not a technicality. It is the mechanism by which a homeowner pays for Class A performance and gets something less. The correct approach is to specify the tested assembly (primary roofing material, underlayment, and decking) as a documented, validated system, not as individual products.
Non-combustible vs. Class A: the honest difference
Tile, natural slate, and metal don't burn. They are non-combustible materials that carry Class A ratings by virtue of their physical composition. There is no organic material to ignite. Asphalt shingles are rated Class A, but they are still combustible. Under standard fire test conditions, they perform to the Class A threshold. Under sustained wildfire ember exposure and direct flame contact, asphalt shingles will eventually ignite. The Class A rating is a minimum performance floor, not a guarantee of survival. Non-combustible materials (metal, tile, slate) are categorically more resilient in actual wildfire conditions than rated-but-combustible products.
What Old Century Roof installs
Every primary roofing system we install is Class A rated or non-combustible:
- Concrete tile: non-combustible, Class A
- Clay tile: non-combustible, Class A
- Natural slate: non-combustible, Class A
- Stone-coated steel: Class A rated
- Standing seam metal: non-combustible, Class A
- Exposed fastener metal: non-combustible, Class A
- Synthetic slate/shake (DaVinci, F-Wave, Brava, Euroshield): Class A rated
- Asphalt shingles (Owens Corning): Class A rated, combustible
Assembly Fire Rating
The layer nobody
talks about.
Most homeowners, and a surprising number of contractors, focus on the primary roofing material when discussing fire ratings. What they overlook is that the underlayment is part of the rated assembly. The fire rating you see on a shingle or panel product is the rating for the full system. The underlayment beneath it is not an afterthought. It is a co-tested component.
Self-adhered underlayments like Grace Ice & Water Shield and Carlisle WIP 300HT contribute directly to Class A assembly ratings. They are part of the documented test assembly, not an arbitrary upgrade. Specifying these products in the correct applications is not a premium option. It is how Class A performance is actually achieved.
High-temperature underlayments are specifically required beneath metal and tile installations where panel surface temperatures can exceed 200°F on a Colorado afternoon at altitude. Standard rubberized asphalt underlayments soften at those temperatures. They deform, lose adhesion, and compromise both the waterproofing function and the fire assembly integrity. The correct specification is a high-temperature rated product: Carlisle WIP 300HT is the standard for metal and tile. Using a standard product under a metal roof to save $0.15 per square foot is the kind of substitution that shows up 10 years later as a warranty exclusion.
Old Century Roof specifies underlayment as part of a complete, documented fire assembly: primary material, underlayment type, application scope, and the tested assembly the combination represents. We put this in writing before a contract is signed.
Metal Roofing
Not all metal roofs
are equal in a fire.
Standing Seam
The most ember-resistant metal roof available.
Standing seam has no exposed fasteners, no open ribs, and no gaps at the eave. Panels interlock through a raised concealed seam and terminate cleanly at the eave with a continuous metal drip edge. No pathways for ember intrusion. The flat, uninterrupted panel surface offers nothing for embers to lodge against.
The system is non-combustible throughout. There is no organic material in the panel, no sealant at fastener penetrations to char and open, no surface texture that holds debris. In a wildfire ember shower, standing seam gives embers nowhere to stay and nothing to ignite.
A firefighter's honest assessment: when crews are triaging which homes in a neighborhood to defend when resources are limited, the house with standing seam metal is the house worth protecting. It buys time. It is the difference between a structure that resists and a structure that succumbs.
Pro Panel / Exposed Fastener
Good product. Known vulnerability. Here's the fix.
Pro Panel (R-panel, corrugated, and similar exposed fastener profiles) is widely used in Colorado mountain construction and is a legitimate, durable roofing system. It is cost-effective, installs faster than standing seam, and handles snow load and high-wind conditions well when properly specified.
There is, however, a documented fire vulnerability that most contractors don't address: the open rib channel at the eave termination. When exposed fastener panel terminates at the eave without a proper closure, the ribbed profile creates a gap between the drip edge and the first panel rib: an opening directly below the panel. In a wildfire ember storm with wind, embers blow up into that gap, travel under the panel, and land on the underlayment and roof deck. From there, ignition happens quickly.
The fix is not complicated or expensive: eave closure strips, metal closures or foam backer rod fitted to the panel rib profile, seal the opening at the termination edge. They cost a fraction of the panel installation and are routinely omitted because most contractors aren't thinking about ember intrusion when they're installing a metal panel roof.
Old Century Roof specifies eave closures on every exposed fastener installation.If your current Pro Panel roof doesn't have them (and most don't), it's worth a conversation. It is one of the least expensive fire mitigations you can make on an existing metal roof.
Ember Pathways
Your gutters could be the most dangerous thing on your roof.
The debris ignition problem
Gutters collect dry organic debris (pine needles, leaves, bark, seed pods) and hold it directly at the edge of your roofline. In a wildfire ember storm, that debris becomes fuel. Once gutter debris ignites, it burns at the eave: flame travels under shingles, into open soffit cavities, through vent openings, and into the attic in a matter of minutes. The gutter is not a minor accessory. In a wildfire, it is a critical component of either defense or failure.
Why vinyl gutters are actively dangerous
Vinyl gutters begin to soften and deform at approximately 170°F, well below the temperatures present in a wildfire ember environment. Under fire conditions, vinyl gutters don't just fail to perform. They melt and drop flaming material onto the deck, vegetation, and structure directly below the eave. A melting vinyl gutter loaded with dry debris is a flaming delivery mechanism attached to your house. If your home is in a WUI zone and has vinyl gutters, that is the first thing to change regardless of what's on the roof.
The foam insert problem
Foam and plastic gutter inserts, including products marketed as “fire retardant,” such as GutterFoam FR, are not a reliable fire defense. Even flame-retardant foam inserts accumulate debris on their upper surface and perform poorly under actual flame exposure in field conditions. Independent testing has demonstrated that many products labeled fire retardant remain combustible under sustained exposure. In the worst cases, a foam insert provides false assurance while actually increasing the organic fuel load in the gutter. The correct answer is not a better insert. It is a different system.
The correct specification
Metal gutters: aluminum or steel, not vinyl
Metal gutters do not melt, do not drop flaming debris, and do not become a fuel delivery system at the eave. This is the baseline.
Metal micro-mesh gutter guards
Stainless steel mesh guards rated ASTM E84 Class A block debris accumulation AND resist ember ignition. The FireStorm brand is the benchmark product. Mesh opening size matters: fine enough to exclude debris, coarse enough to pass water without backing up.
Metal drip edge: the frequently omitted detail
Metal drip edge closes the critical gap between the roof deck edge and the gutter. It is required by CAL FIRE home hardening standards and frequently omitted on Colorado installations. Without it, there is a direct opening from the gutter cavity to the underlayment and deck edge.
Old Century Roof can specify and coordinate the complete gutter system (gutters, guards, and drip edge) as part of any roofing project.
The Full Picture
What a properly hardened
roof looks like.
Class A or non-combustible primary roofing material
High-temp rated underlayment appropriate for the assembly
Metal drip edge at all eaves
Eave closures on any exposed fastener panels
Metal gutters (not vinyl)
Metal micro-mesh gutter guards, ASTM E84 Class A rated
Ember-resistant soffit and vent screens
Keep roof penetrations and valleys clear of debris year-round
Most contractors address the shingles. We address the system.
Old Century Roof specifies and installs all of these components as a coordinated assembly. The primary material, the underlayment, the drip edge, the eave closures, the gutter system, the vent screens: each one is specified in writing before the contract is signed, and each one is installed to the standard it requires. This is what a complete wildfire-hardened roof looks like.
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