Home hardening means replacing the materials and closing the gaps that let wind-blown embers, flames and radiant heat ignite a house: a Class A roof with the voids under it sealed, ember-resistant vents, enclosed eaves, dual-pane tempered windows, noncombustible material at the base of the walls, a deck and attached fence that cannot carry fire to the house, and a clear five-foot zone around it. As of 10 October 2026, no statewide Zone 0 rule is in force: the Board of Forestry adopted emergency regulations on 19 August 2026, and the Office of Administrative Law lists the filing as withdrawn on 8 September 2026. What is in force is the 2025 California Wildland-Urban Interface Code, effective 1 January 2026, which governs new and modified construction in fire hazard zones, and the Department of Insurance’s Safer from Wildfires rules, which require insurers to offer discounts for specific upgrades.
We are Green Design and Build, a licensed residential general contractor based in Van Nuys (CSLB #1110975), working across Los Angeles, Orange and Ventura counties and western Riverside and San Bernardino counties. Roofing, windows and doors, stucco, fencing, patio covers, new decks, concrete, pavers and landscaping are all work we do. This guide gives no prices — hardening scopes vary too much from house to house — and links to our cost guides where a number helps. It is general information, not legal or insurance advice.
What home hardening is, and why embers are the main target
A wildfire ignites a house by direct flame, radiant heat or flying embers, and CAL FIRE’s Ready for Wildfire program notes that embers can ignite homes up to a mile from the fire. An ember that lands in a gutter full of needles, slips through a vent, or lodges under roof tiles can start a fire long after the flames have passed. That is why most hardening is about small openings and small fuels.
The yardstick is one-eighth of an inch. CAL FIRE’s home hardening guide treats vent openings, wall gaps and door gaps larger than 1/8 inch as vulnerabilities, and the code uses the same figure for vent mesh, skylight screens and garage door gaps. Hardening is the house itself; defensible space is the land around it. The five-foot zone against the walls is where the two overlap.
Is your home in a Fire Hazard Severity Zone?
The Office of the State Fire Marshal maps Fire Hazard Severity Zones in three classes: Moderate, High and Very High. Maps for State Responsibility Areas took effect on 1 April 2024; maps for Local Responsibility Areas, which include most cities, were released to local governments in four phases between 10 February and 24 March 2025. The State Fire Marshal’s Fire Hazard Severity Zones page links to address-lookup viewers for both. If you last checked before 2025, check again: the local maps were redrawn that year.
The zone decides three things: whether the 2025 WUI Code applies to work on your house, whether defensible-space law applies, and what you must disclose when you sell. The maps measure hazard — terrain, vegetation, weather — not the condition of your house, which is why the insurance rules below look at the house itself.
Zone 0 in California: where the rule stands on 10 October 2026
Short answer: Zone 0 is required by statute, but the regulations that define it are not in effect, so it cannot be enforced today.
Public Resources Code §4291 (State Responsibility Areas) and Government Code §51182 (locally designated Very High zones) require 100 feet of defensible space, including an ember-resistant zone within five feet of the structure; §4291 counts an attached deck as part of the structure. The Board of Forestry and Fire Protection writes the details. Under §4291, the five-foot zone applies to new structures once the Board’s regulations and guidance are updated, and to existing structures three years after that. The sequence so far:
- 19 August 2026: the Board adopted emergency Zone 0 regulations.
- 28 August 2026: the package was filed with the Office of Administrative Law as file 2026-0828-03E.
- 8 September 2026: the Office of Administrative Law’s record of recent emergency actions lists the file as withdrawn.
- 10 October 2026: no Zone 0 filing is on OAL’s list of emergency regulations under review, and the Board’s Zone 0 project page says staff are working with OAL on a final review.
The Board’s August 2026 summary of the withdrawn draft shows the direction, though the final text may change: no bark or wood-chip mulch, leaves or firewood within five feet; only low, sparse, non-woody plants, kept clear of windows, doors and vents; no combustible fence or gate attached to the house, and no new combustible fencing within five feet; and a three-to-five-year phase-in for most requirements on existing homes. Our view: the five-foot zone is the cheapest, most effective part of hardening and already counts toward an insurance discount, so waiting saves nothing.
City of Los Angeles: brush clearance already applies
In the City’s Very High Fire Hazard Severity Zone, the LAFD’s brush clearance requirements (LAMC 57.4906.5.2) already require year-round clearance of hazardous vegetation within 200 feet of structures, five feet of vertical clearance between roofs and overhanging trees, and roofs kept free of leaves and needles.
What the 2025 California WUI Code requires for new work
On 1 January 2026, California moved its wildfire construction rules out of the building and residential codes into a standalone code, the 2025 California Wildland-Urban Interface Code (Title 24, Part 7). Section 503.1 applies its Chapter 5 to buildings “hereafter constructed, modified or relocated” into or within a wildland-urban interface area: a state-mapped Fire Hazard Severity Zone, or another area your enforcing agency designates.
A detail for owners of older homes: the July 2025 printing exempted additions and remodels of buildings built before 1 July 2008, but the current January 2026 errata text no longer carries that exception. If you are adding on or remodeling in a fire zone, plan on the new work meeting Chapter 5, and ask the building department early how it applies to your scope. The code does not require you to retrofit a house you are not working on.
| Element | Section | What new work must meet | Retrofit on an existing house |
|---|---|---|---|
| Roof | 504.2, 504.2.1, 504.2.2 | Class A assembly; voids under tile or other profiled roofing closed with a 72 lb cap sheet or listed Class A underlayment, bird stops and mudded hip and ridge; 26-gauge metal valleys | Seal gaps at eaves and ridge; specify the full assembly at replacement |
| Vents | 504.10 | State Fire Marshal-listed flame and ember resistant vents; sloped-roof vents may use 1/16 to 1/8 inch noncombustible mesh; new gable vents 10 ft from lot lines | Listed vents, or 1/16 to 1/8 inch metal mesh |
| Eaves | 504.3 | Noncombustible or ignition-resistant underside, 2-inch lumber, or a listed assembly | Enclose open eaves; caulk gaps at rafter tails |
| Gutters | 504.4 | Noncombustible, with an approved debris guard | Metal gutter cover and drip edge |
| Walls | 504.5 | Noncombustible or ignition-resistant covering, foundation to roof; 6 in of metal flashing at ground, deck and roof joints | Repair stucco; noncombustible base; seal gaps |
| Windows | 504.8 | Multilayer glazing with one tempered pane, or 20-minute rated | Dual-pane tempered units |
| Doors | 504.9 | Noncombustible, 1-3/4 in solid-core wood, or 20-minute rated; garage door gaps 1/8 in maximum; opener battery backup | Weather-strip and flash the garage door |
| Decks | 504.7.3 | 6-inch flashing at deck-to-wall joints; walking surface from the code’s approved list | Clear underneath; flash at the house |
| Patio covers | 504.11 | Within 3 ft of the house: noncombustible or ignition-resistant | Replace a wood cover against the house |
Two more rules. Section 503.2.5 says paints, coatings and stains are not an approved method of protection, so fire-retardant paint does not make wood siding compliant. Section 507.1 says that when an existing roof covering is replaced, or 50% or more of it within 12 months, the new covering must meet the new-construction roof requirements, and any roofing applied during an addition, alteration or repair must be at least Class A.
Component-by-component: how to harden each part of the house
Roof
CAL FIRE lists asphalt shingles, tile and metal panels as common Class A roof coverings. On Southern California houses the weak points are usually around and under the roofing: open ends of barrel tile at the eaves, gaps at the ridge, debris in valleys and old underlayment. That is why the code calls for bird stops, mudded hip and ridge caps, and a cap sheet or Class A underlayment.
If your roof is near the end of its life, harden it on your schedule rather than after a leak. See how long a roof lasts in Southern California, roof replacement cost, whether a roof replacement needs a permit in Los Angeles, and our roofing services.
Vents
Attic, soffit, gable and crawlspace vents let air in, and embers with it. The best answer is a vent listed by the State Fire Marshal as flame and ember resistant; the retrofit answer is noncombustible, corrosion-resistant metal mesh between 1/16 and 1/8 inch. Ready for Wildfire warns that fiberglass or plastic mesh can melt, and CAL FIRE cautions that fine mesh reduces airflow, so confirm the attic still meets its ventilation requirement — often a reason to swap in listed vents rather than screen old ones.
Eaves and gutters
Open eaves with exposed rafter tails trap heat and embers where the wall meets the roof. Enclosing them with a noncombustible or ignition-resistant soffit, and plugging gaps around rafter tails, is on the insurance discount list. A gutter full of leaves is a fuel bed on the roof edge: CAL FIRE recommends a noncombustible gutter cover, a metal drip edge, and metal gutters when they are replaced.
Windows and doors
Radiant heat can break glass before flames arrive, letting embers into the house. CAL FIRE says tempered glass is about four times more resistant to breaking during a wildfire, and the code’s baseline is multilayer glazing with at least one tempered pane. Specify tempered glass when ordering replacements rather than assuming it. Garage doors are a common ember entry: weather-strip them, flash the jambs and header, and keep gaps to 1/8 inch or less. See window replacement cost in Southern California and our window and door replacement services.
Exterior walls and siding
Three-coat cement stucco is a noncombustible finish and a common one on Southern California homes. The problems are cracks, gaps around penetrations, weep screeds buried in mulch, and wood trim at the base of the wall. The insurance discount list includes noncombustible material on the bottom six inches of exterior walls, and CAL FIRE suggests noncombustible siding on the bottom two feet as a partial step. Our guide to stucco repair and re-stucco explains when patching is enough; exterior painting and stucco covers finishing.
Decks
An attached wood deck is fuel against the wall. On an existing deck, CAL FIRE recommends clearing everything combustible from underneath, putting gravel, pavers or concrete beneath it and five feet out, and using noncombustible boards for the first foot from the house as a partial measure. For new decks in a fire zone, not every composite board qualifies — check for the WUI listing in the product documentation. See repair or replace your deck, and composite vs. wood and our deck and outdoor kitchen services; we build new decks rather than repairing old ones.
Fences and gates: what a fire-resistant fence looks like
A wood fence that runs up to a house works like a wick. CAL FIRE recommends noncombustible material for the first eight feet of any fence or gate attached to the house, and keeping parallel combustible fences at least 10 feet apart. The insurance discount list includes replacing wood fencing attached to the home with metal. A fire-resistant segment is steel, aluminum or wrought-iron panels, or block masonry, with a metal gate; many owners keep the rest of the fence and replace only the run that touches the house. Vinyl and composite are plastics, not noncombustible materials. See fence installation cost in Southern California and our fencing services.
Patio covers and sheds
A wood patio cover attached to the house extends the fire path to the eaves. Under the 2025 code, permitted patio covers, trellises and gazebos within three feet of the house must be noncombustible or ignition-resistant. Aluminum is noncombustible, which suits a cover attached to the house; we are an authorized Alumawood installer, and our patio cover services page shows the options. For sheds, the discount list counts moving combustible outbuildings at least 30 feet away.
The five-foot ember-resistant zone: what to change around the house
Whatever the final Zone 0 text says, every piece of state guidance asks for the same work in the first five feet:
- Replace bark and wood-chip mulch with gravel, decomposed granite, concrete or pavers.
- Clear dead plants, leaves and needles from the ground, roof, gutters and under decks.
- Move firewood, lumber, bins and patio cushions out of the zone.
- Keep plants low and sparse, clear of windows, doors and vents, and trim branches off the roof.
- Replace the fence or gate section that connects to the house with a noncombustible one.
A concrete or paver walkway around the house — classic hardscaping — solves several of these at once. See concrete patio cost and paver patio cost, and our landscaping and irrigation services for the planting beyond five feet, where well-watered, well-spaced plants are part of the same defensible-space requirement.
Upgrades that can earn an insurance discount in California
Short answer: California requires insurers to offer discounts for a set list of mitigation actions, but amounts vary by company, so ask your insurer or broker what yours pays. The rule is the Safer from Wildfires regulation (Title 10, California Code of Regulations, §2644.9), and the Department of Insurance’s Safer from Wildfires page lists the actions:
| Safer from Wildfires action | Related guide or service |
|---|---|
| Class A fire-rated roof | Roofing |
| Ember- and fire-resistant vents (1/16 to 1/8 inch metal mesh) | Roofing |
| Noncombustible material on the bottom 6 inches of exterior walls | Stucco repair |
| Enclosed eaves | Stucco and soffits |
| Upgraded windows (multi-pane glass or shutters) | Window replacement cost |
| 5-foot ember-resistant zone, including replacing wood fencing attached to the home with metal | Fence installation cost |
| Vegetation and debris cleared from under decks | Deck guide |
| Combustible sheds and outbuildings moved at least 30 feet away | Ask us |
| Defensible space compliance | Landscaping |
| Firewise USA site or Fire Risk Reduction Community | Through your neighborhood or city |
According to the Department of Insurance FAQ:
- Tell your insurer, agent or broker the work is done. You may need to show proof, or the insurer may inspect.
- Ask for your wildfire risk score; insurers must provide and explain it after you complete mitigation, including how to lower it.
- If you think it is wrong, appeal to the insurer, and if that fails, the Department of Insurance helps at 800-927-4357.
- Savings start with your next policy period. The California FAIR Plan also offers discounts, through a licensed broker.
Keep the permit and final inspection, the invoice describing the work, product data showing the roof’s Class A rating and the vents’ State Fire Marshal listing, and dated before-and-after photos.
Selling a home in a High or Very High zone: what you must disclose
Civil Code §1102.19 applies to sales on and after 1 July 2021: where a local ordinance or inspection program provides for it, the seller gives the buyer documentation of defensible-space compliance, or the parties agree the buyer will obtain it. Civil Code §1102.6f applies to homes built before 1 January 2010: the seller discloses known vulnerabilities — vents over 1/8 inch or not ember-resistant, untreated wood shake roofs, combustible landscaping within five feet, single-pane or non-tempered windows, missing bird stopping or flashing, uncovered gutters — and, since 1 July 2025, which items on the state’s low-cost retrofit list were completed. Hardening before you list turns that form into a list of fixes. Your agent or attorney should advise on the forms.
Where to start: a priority order for an existing house
- The five-foot zone. Low cost, immediate effect, and a discount item.
- Vents and gutters. Listed vents or fine metal mesh, and noncombustible gutter guards.
- The attached fence and gate. Replace the run that touches the house with metal or masonry.
- Eaves and wall base. Enclose open eaves, repair stucco, and add a noncombustible base.
- Windows. Dual-pane tempered units, starting with walls facing brush or a slope.
- Roof, deck and patio cover. When each is due, specify fire-zone materials and details.
Cost is driven mostly by access and how much existing material must come off: a single-story stucco house with a simple roof is far easier than a hillside house with open eaves, a raised deck and a long fence line. Bundling items that share a trade — vents and gutters with a re-roof, soffits with stucco — can save a mobilization and sometimes a separate permit. A rebuild after a fire is built to the code from the start; see our fire rebuild services. Planning an addition in a fire zone? The new work is built to Chapter 5 too; see room additions.
Home hardening FAQs
What is home hardening?
Home hardening is upgrading a house’s materials and closing its openings so it resists ignition from wildfire embers, flames and radiant heat. The core items are a Class A roof with sealed voids, ember-resistant vents, enclosed eaves, noncombustible gutters, dual-pane tempered windows, a noncombustible wall base, fire-resistant decks and attached fences, and a clear five-foot zone.
Is Zone 0 required in California yet?
Not yet. State law requires an ember-resistant zone within five feet of structures in State Responsibility Areas and Very High zones, but only through Board of Forestry regulations. The Board adopted emergency regulations on 19 August 2026; the Office of Administrative Law lists the filing as withdrawn on 8 September 2026. As of 10 October 2026, no Zone 0 regulation is in effect.
What is the 2025 California Wildland-Urban Interface Code?
It is Title 24, Part 7 of the California Code of Regulations, effective 1 January 2026, which took over the wildfire construction rules formerly in the building and residential codes. Chapter 5 sets ignition-resistant requirements for roofs, vents, eaves, gutters, walls, windows, doors, decks and accessory structures built or modified in Fire Hazard Severity Zones.
Does the WUI code force me to upgrade my existing house?
No. It applies to work you do — new buildings, additions, remodels and other modifications in a mapped zone, and roof replacements of 50% or more within 12 months. Defensible-space and brush-clearance rules do apply to existing homes, and the five-foot zone will once the Board’s regulation takes effect.
What is a fire-resistant fence?
A fence built of noncombustible material such as steel, aluminum, wrought iron or masonry. The section that matters most is the part attached to the house: CAL FIRE recommends noncombustible material for the first eight feet, and the insurance discount list includes replacing attached wood fencing with metal.
Which home hardening upgrades earn an insurance discount in California?
Insurers must offer discounts for a Class A roof, ember- and fire-resistant vents, a noncombustible bottom six inches of wall, enclosed eaves, upgraded windows, a five-foot ember-resistant zone, clearing under decks, moving sheds 30 feet away, defensible-space compliance, and Firewise USA or Fire Risk Reduction Community participation. Amounts vary by insurer.
Are ember-resistant vents required?
On new work in a Fire Hazard Severity Zone, yes: the 2025 WUI Code requires State Fire Marshal-listed flame and ember resistant vents (or vents tested to ASTM E2886), with a 1/16 to 1/8 inch mesh option for vents on sloped roofs. On an existing house they are voluntary, but they are on the discount list and the job is small next to a roof or window replacement.
How do I find out if my home is in a Fire Hazard Severity Zone?
Use the address lookup viewers on the Office of the State Fire Marshal’s Fire Hazard Severity Zones page, which has separate viewers for State and Local Responsibility Areas. Your city or county building department can confirm the zone for your parcel and how it enforces the code.
Plan your hardening work with a licensed contractor
We can walk the house with you, check it against the 2025 WUI Code and the insurance discount list, and give you a written scope sorted into what to do now and what to do when each item comes due. Site visits take about two hours, we reply within one business day, and proposals arrive within 48 hours. Call (800) 348-3050, 8am to 6pm daily, or send us your project details.