Retrofitting an Existing Home: Priority Order and Cost Ranges

If you already own a home in a fire zone, you are not starting from a blank piece of paper. You have a roof of some age, vents of some design, a deck that may be attached to the house, and siding that was chosen more for looks than for fire performance. The question is not whether your house is already hardened — it almost certainly isn't — but which upgrades, in which order, buy you the most protection per dollar.

That's what this article is for. We'll walk through a priority order that has held up across the IBHS research, post-fire damage assessments from CAL FIRE, and the practical experience of contractors working in the wildland-urban interface. We'll put realistic 2025–2026 cost ranges against each step for a typical 2,000 sq ft single-family home in the Western U.S. And we'll be honest about what a limited budget can and cannot accomplish.

If you haven't already, it's worth reading what home hardening is and why it matters before you start making spending decisions. The priority order below assumes you understand why embers — not walls of flame — are the primary threat.

The priority order, in one paragraph

For almost every existing home, the highest-impact-per-dollar retrofit sequence looks like this: first, clear Zone 0 (the first five feet around the house). Second, upgrade vents to ember-resistant products. Third, upgrade the roof to a Class A assembly if it isn't already. Fourth, address decks. Fifth, deal with gutters. Sixth, replace combustible siding over time. Seventh — and only if budget allows or they're already failing — upgrade windows.

Everything else in this article is an elaboration on that sequence.

Step 1: Zone 0 cleanup — $500–$3,000

Start here. This is the cheapest, fastest, highest-leverage thing you can do, and it requires no permit, no contractor license, and no product selection.

Zone 0 is the first five feet measured outward from any exterior wall, deck, or attached structure. California formalized it in AB 3074, and the concept is now baked into IBHS's Wildfire Prepared Home standard. The goal is simple: nothing combustible within five feet of the house.

What that looks like in practice:

• Remove bark mulch, wood chips, and pine straw from beds against the house. Replace with gravel, decomposed granite, or bare soil.
• Move firewood piles, propane tanks where possible, and lumber storage away from the house.
• Remove or relocate combustible shrubs — especially juniper, arborvitae, and ornamental grasses — within the 5-foot band.
• Clear leaves and needles from the roof, gutters, and the ground against the foundation.
• Disconnect any wood fence or wood gate that runs directly into the siding. The last 5–10 feet should be metal or masonry.

Cost is almost entirely labor. A homeowner with a weekend and a truck pays essentially nothing. A landscaping crew running an 8-hour day is typically $500–$1,500. Larger properties with mature plantings, heavier debris, or rock replacement work can run $2,000–$3,000. Budget another few hundred dollars a year for ongoing maintenance — Zone 0 is not a one-time project. For more detail, see our guide to defensible space Zones 0, 1, and 2.

Step 2: Ember-resistant vents — $500–$2,500

Vents are the single most common ignition path for WUI home losses, and also one of the cheapest to fix. A typical 2,000 sq ft house has somewhere between 8 and 20 vents — gable, soffit, foundation, dryer, roof. Any one of them, if it admits embers, can ignite insulation, framing, or stored material inside.

The retrofit options, roughly in order of increasing cost and performance:

1. 1/8-inch metal mesh behind existing louvered vents. Code minimum under California Chapter 7A; cheap and effective against coarse embers. Not a substitute for tested flame-and-ember-resistant products in the worst exposures.
2. Ember-resistant vent retrofit kits (Vulcan, Brandguard, O'Hagin, and similar) tested to ASTM E2886. These replace or cover the existing vent with a product that resists both embers and flame intrusion.
3. Full vent replacement with a listed assembly, usually done during reroofing or residing.

For whole-house retrofits using listed products, expect $500–$2,500 including labor for a typical home. Mesh-only retrofits are cheaper — often a few hundred dollars — but give up meaningful performance in severe exposures. If you're going to spend the money on one category early, this is the one where spending a little more on listed products is clearly worth it. See our explainer on ember-resistant vents for how the testing works.

Step 3: Class A roof — $15,000–$60,000+

The roof is the largest single ember-catcher on the house and the most consequential material decision. If you have a wood-shake roof, replacing it with a Class A assembly is almost always the most important capital project in the hardening sequence — and in California, wood shakes on a new or re-roofed house have been prohibited on re-roofs in WUI areas for years.

Cost depends heavily on material choice and whether the existing deck and structure can carry the load:

Tile roofs on houses that weren't originally framed for them may need structural upgrades that push the total higher. Asphalt Class A remains the cost leader and is what most hardening retrofits end up using. For a deeper look at the rating system, see Class A roofing explained.

A practical note: if your existing roof is within 5–8 years of end-of-life, it almost always pays to accelerate replacement and combine it with the hardening retrofit. You avoid doing the work twice and you get the insurance benefit earlier.

Step 4: Decks — $8,000–$40,000

An attached wood deck is one of the most common ignition paths in post-fire surveys. Embers fall through the board gaps, accumulate in whatever has blown under the deck, and ignite from below. Options, from cheapest to most thorough:

• Clean under the deck and seal the perimeter — cheapest, mostly labor, $500–$1,500. Combined with non-combustible decking board replacement, this is a real improvement.
• Replace deck boards with ignition-resistant or noncombustible product (composite rated for WUI, aluminum, concrete paver deck). $8,000–$25,000 for a typical 200–400 sq ft deck.
• Full deck replacement with noncombustible structure and boards and a solid enclosed skirt underneath. $20,000–$40,000+ depending on size, railings, and framing.

If the deck is structurally sound and the only issue is the deck boards and the space under it, you can usually get most of the fire benefit for a fraction of a full replacement. If the deck is old, undersized, or you were planning to remodel it anyway, bundle hardening into that project.

Step 5: Gutters and eaves — $2,000–$8,000

Gutters full of dry leaves are among the most reliable ember traps on the house. Open eaves channel any heat that builds up along the wall straight into the attic.

Cost ranges for a typical home:

• Non-combustible (metal) gutters with gutter guards: $2,000–$5,000.
• Enclosing open eaves with soffit panels (fiber cement or metal): $3,000–$8,000 depending on complexity and paint.

Neither of these is glamorous, but they are high-leverage. Gutter guards alone won't save a house — they reduce but don't eliminate accumulation — and they have to be cleaned annually regardless. But combined with enclosed eaves and ember-resistant vents, they close off one of the primary attic-ignition pathways.

Step 6: Siding — $20,000–$60,000

Siding replacement is a big project and usually sequenced last among the major exterior upgrades, partly because of cost and partly because siding performance matters most when radiant heat exposure is severe — which is a smaller share of ember-driven losses than vents, roofs, and decks.

Fiber cement (Hardie board and similar) is the common retrofit choice: Class A rated, looks like traditional lap siding, holds paint, and is widely available. Stucco is even better from a fire standpoint and is standard on much new Western construction. Brick and stone are excellent but rarely used for retrofits.

Cost ranges for a 2,000 sq ft home:

Two notes. First: if you are planning a repaint and the existing siding is vinyl or wood in bad shape, this is the moment to combine residing with hardening. Second: "fire-retardant paint" is not a substitute for noncombustible siding. Intumescent coatings have legitimate uses in specific commercial applications; as a retail product marketed to homeowners as a way to "fireproof" existing wood siding, the performance is nowhere near what Class A or noncombustible assemblies deliver. More on this in the contractor article.

Step 7: Windows — $15,000–$50,000

Windows are last on this list, which surprises some homeowners. The reasoning: single-pane windows are genuinely a liability in a severe radiant-heat exposure, but most WUI losses are ember-driven, and the other steps above address embers directly. Windows matter most when a burning neighbor or burning vegetation is radiating heat onto the wall — an important case, but one that already depends on other mitigations working.

That said, if your windows are already failing, or you are remodeling, upgrade them. The Chapter 7A baseline is dual-pane with at least one tempered pane. Costs for a typical home:

• Per-window replacement cost (dual-pane, one tempered pane): $800–$1,500 installed, depending on size and trim complexity.
• Whole-house window replacement: $15,000–$50,000 depending on count, size, and whether you upgrade frames.

If you have 3–4 large picture windows facing the worst fuel exposure, consider upgrading those first rather than doing the whole house at once.

Putting it together: three budget scenarios

The next article in this series covers this in detail, but here is the short version for the three scenarios homeowners most commonly ask about.

• $5,000 budget: Zone 0 cleanup, mesh or listed vent retrofit, gutter guards, under-deck cleanup. You are buying the highest-leverage ember mitigations without touching the major structural components.
• $25,000 budget: All of the $5K items, plus listed ember-resistant vents, non-combustible gutters, enclosed eaves, and deck board replacement with ignition-resistant or noncombustible product. Possibly one or two upgraded high-exposure windows.
• $100,000 budget: All of the above plus Class A roof replacement, deck replacement, and partial residing or full stucco. You are approaching — though not quite reaching — a full IBHS Wildfire Prepared Home Plus retrofit, which typically runs $75,000–$200,000 for a 2,000 sq ft home.

What this sequence assumes — and what it doesn't

A few caveats worth stating plainly:

• The priority order assumes you are starting from a reasonably ordinary older home without obvious red flags. If your house has a wood-shake roof, skip to step 3 immediately — a combustible roof dominates every other risk on the list.
• The cost ranges are 2025–2026, Western U.S., reasonably competitive market. High-cost metros and island-like markets run higher. Very rural areas with limited contractor supply run higher too.
• These are whole-house figures. Partial retrofits — half the vents, one side of the roof — don't scale linearly because of mobilization and permit costs.
• None of this replaces defensible space maintenance. A hardened house with dry grass to the foundation and firewood against the siding is not hardened in any meaningful sense.

The bottom line

A serious retrofit is not a single weekend project, and it isn't a single check you write to one contractor. It's a sequence. For most homeowners, the sequence above — Zone 0, vents, roof, decks, gutters, siding, windows — delivers more protection per dollar than any other order, and it matches how the research, the codes, and the insurance discount programs are all structured.

Start with the cheap high-leverage steps this month. Plan the capital projects — roof, siding, deck — over a horizon of three to five years, timed to the end of each component's useful life. By the time you're through the list, you will have a house that costs more than it did when you started, but one with real odds of still being standing after a fire that takes out the house next door.

This article is informational and not a substitute for licensed professional advice. Cost ranges are general estimates and vary widely by region, house specifics, and market conditions. Before committing to retrofit or new-construction work, consult a licensed contractor with WUI experience, your local building department, and your insurer.