Home Hardening Guide
Home Hardening: Your Home's Exterior Decides Whether It Survives
Most homes lost to wildfire aren't reached by flames.
They're ignited by embers — burning fragments carried by wind, landing in vents, gutters, gaps in siding, and on decks. Defensible space buys your home time. Home hardening is what keeps the structure itself from igniting when embers arrive.
You need both.
This page focuses on the building itself. For the vegetation and zones around it, see Defensible Space: What It Is and Why It Works →.
How Homes Ignite
Three ways:
Embers.
The most common. Burning debris thrown a mile or more ahead of the fire front. Embers collect in gutters, against siding, under decks, and in vents. They find something small to burn — dry needles, a cedar shake, an unscreened vent — and the building fire starts from there. By the time the main fire arrives, the home is already on its way.
Radiant heat.
Burning vegetation or a neighboring structure close to your home can crack single-pane windows, melt vinyl siding and soffits, and ignite combustible deck materials — all without flame ever touching the structure.
Direct flame contact.
Fuel touching or overhanging your home — a wooden fence, overgrown shrubs against the siding, a branch over the roof — carries flame directly to the structure.
Home hardening addresses all three at the point where they matter most: the exterior of your home.
The Components That Matter Most
Roof
The largest surface exposed to falling embers. The most important component to get right.
Class A fire rating is required — metal, asphalt composition, concrete tile, clay tile, or slate
Cedar shake is the highest-risk roofing material in wildfire country
Keep the roof clear of needles and debris, especially in valleys and where the roof meets walls
Clean gutters regularly — dry leaves and needles in a gutter are one of the most common ignition points
Vents
The most overlooked entry point for embers.
Every vent needs 1/8-inch metal mesh screening — attic, soffit, foundation, crawl space, gable, ridge, dryer, exhaust
If you can fit a pencil tip through the mesh, it's too large
This is a screwdriver-and-hardware-store fix for most vents
Eaves and Soffits
Open eaves expose rafters where embers collect and ignite.
Enclosed (boxed) eaves are significantly more resistant than open
Soffit material matters — fiber cement or metal, not vinyl (vinyl melts)
Check for gaps, holes, or sagging panels
Siding
The vertical surface most exposed to radiant heat.
Non-combustible options: fiber cement, stucco, brick, stone, metal
Maintain 6 inches of clearance between ground and the bottom of siding
Seal gaps where utility lines, pipes, or conduit penetrate the wall
Windows, Doors, and Skylights
Single-pane glass shatters at temperatures well below what a vegetation fire produces — once the glass fails, the interior ignites.
Multi-pane or tempered glass resists heat far better than single-pane
Install metal screens on the exterior of windows to block embers and reduce radiant heat
Exterior doors should be solid core, not hollow
Check garage door seals — if you can see daylight from inside, embers can get in
Skylights are a known weak point — single-pane and plastic skylights are especially vulnerable
Replace plastic pet doors with metal-framed versions, or block them off during fire weather
Decks
A burning deck transmits fire directly to your walls and eaves.
Clear everything off and under the deck — no storage, no firewood, no cushions
Screen under-deck spaces with 1/8-inch metal mesh
Remove combustible attached structures (trellises, arbors, pergolas) connecting to the house
Fencing
A wooden fence attached to your house is a direct fire path to the structure.
Fencing within 5 feet of the structure should be non-combustible — metal, stone, or masonry
If you have wood fencing attached to the house, replace the first 5 feet with metal
Clear vegetation along both sides of all fence lines
Chimney
Install a spark arrestor (1/2-inch mesh cap) — your chimney produces its own embers
Clear all branches within 10 feet of the chimney
Common Myths
A metal roof is all I need.
Roof material matters enormously, but embers also enter through vents, burn on decks, and ignite combustible siding. A metal roof above open eaves, unscreened vents, and cedar trim is a house with one good defense and several open doors.
My house is new, so it's already fire-resistant.
Not automatically.
Colorado doesn't have a statewide wildland-urban interface building code, and requirements vary by jurisdiction. Newer homes often have better roofing and windows than older ones, but vents, eaves, decks, and landscaping choices still matter — and many new homes have been lost in recent Colorado wildfires.
I can't afford to replace my roof, so there's no point.
The highest-impact fixes are usually not the most expensive ones. Screening vents, cleaning gutters, clearing under decks, moving firewood away from siding, and sealing wall penetrations are cheap or free — and they address the ignition points that cause most structural losses.
What Makes the Gunnison Valley Different
Wind-driven embers.
Downslope and downcanyon winds common in our area can carry embers miles ahead of a fire front. Vent screening and gutter maintenance matter more here than in calmer environments.
Older housing stock.
Many Gunnison Valley homes predate modern fire-resistant standards. Cedar shake, wood siding, open eaves, single-pane windows, and unscreened vents are common — and all of them are addressable.
Snow load hides problems.
Winter snow and ice movement creates gaps in flashing, damages soffits, and tears off gutters. Each spring, inspect what winter left behind before fire season starts.
Home Hardening and Your Insurance
Under Colorado HB25-1182, insurance companies must consider documented wildfire mitigation when calculating risk and setting premiums.
The structural hardening items on this page are exactly what insurers look for — Class A roof, enclosed eaves, dual-pane windows, screened vents, noncombustible siding. Documented hardening work can directly affect what you pay every year.
Where to Start
This weekend.
Clean needles and debris from your roof, valleys, and gutters. Screen vents with 1/8-inch metal mesh — hardware store fix. Clear everything stored under your deck. These address the most common ember-ignition points, and most of the fix is free or under $50.
This month.
Address fencing within 5 feet of the structure. Clear the ground-to-siding gap. Seal wall penetrations where utilities enter. Check window condition and install exterior metal screens.
Plan for.
Roof replacement if you have cedar shake. Window upgrades from single-pane to multi-pane or tempered glass. Siding replacement to non-combustible materials. Enclosing open eaves. These are bigger investments that fundamentally change your home's fire resistance — and they're the items most likely to qualify for insurance mitigation credits under HB25-1182.
Download our free homeowner checklist to work through the basics on your own →
This page is intentionally simplified — general guidance that applies to most Gunnison Valley homes. A professional assessment gets specific: which features on your particular structure are the highest priority, what local conditions change the calculation, and what documentation your insurer will actually want to see. The principles are the same; the priorities are different for every home.
For a full hardening assessment — including insurance-grade documentation — get in touch. We document what needs to happen, help you prioritize what to do first, and connect you with the right contractors for the structural work we don't perform ourselves.
Based on Colorado State Forest Service (CSFS) Home Ignition Zone guidelines, NFPA 1140 (2022, formerly NFPA 1140), and IBHS Wildfire Prepared Home criteria.