Defensible Space & Home Hardening
The complete guide to the work that measurably lowers your wildfire risk — and unlocks insurance discounts. The zones, the step-by-step checklist, what it costs, the grants that pay for it, and the products and pros that get it done.
Last updated June 2026 · FireRisk.ai editorial team
See your property's mitigation plan →Defensible space is the managed buffer between a building and the grass, trees, shrubs, and wildland that surround it. It slows or stops an advancing wildfire and gives firefighters room to defend the home. In California, the law sets it at 100 feet around a structure, managed in three zones that get stricter the closer you get to the wall.
California's Public Resources Code § 4291 requires maintaining defensible space of 100 feet from each side, front, and rear of a structure (but not beyond the property line) in State Responsibility Areas. AB 3074 (2020) amended that law to add a required ember-resistant zone within 5 feet of the structure (Zone 0) and more intense fuel reduction between 5 and 30 feet. See CAL FIRE's Defensible Space Zones 0, 1 & 2.
The three defensible-space zones
Work outward from the structure. The first five feet matter most.
0–5 ft · Ember-resistant zone
The newest and most critical zone. Nothing combustible touching the house: no bark mulch, no wood fences attaching to the wall, no stored firewood, no plants under windows. Gravel, stone, or bare soil only. This 5-foot ring stops the embers that ignite most homes.
5–30 ft · "Lean, clean & green" zone
Keep it irrigated and low. Space shrubs, remove dead plants and leaf litter, limb tree branches 6–10 ft off the ground to break "ladder fuels," and keep tree canopies at least 10 ft apart and away from the structure.
30–100 ft · Reduced-fuel zone
Break up fuel continuity so a crown fire drops to the ground. Mow grass to 4 in, create horizontal and vertical spacing between trees and shrubs, and remove dead vegetation. On slopes, extend this zone farther downhill.
How to create defensible space, step by step
In order of impact — start at the wall and work outward.
- 1
Clear the 0–5 ft ember-resistant zone (Zone 0). Remove everything combustible within 5 feet of the structure: bark mulch, stored firewood, plants under windows, door mats, and wood fencing that touches the wall. Replace with gravel, stone, pavers, or bare soil. Under California PRC 4291 as amended by AB 3074, the first 5 feet is designated an ember-resistant zone.
- 2
Harden the vents. Retrofit attic, eave, and foundation vents with 1/16-inch ember-resistant metal mesh or listed intumescent vents to block the embers that ignite most homes through the attic.
- 3
Clean the roof and gutters. Clear leaves and pine needles from the roof and gutters and install metal gutter guards so embers have no fine fuel to land in.
- 4
Create the lean, clean & green Zone 1 (5–30 ft). Remove dead plants and leaf litter, space shrubs apart, limb tree branches 6–10 ft off the ground to break ladder fuels, and keep tree canopies at least 10 ft apart and away from the structure.
- 5
Reduce fuel in Zone 2 (30–100 ft). Mow grass to 4 inches, create horizontal and vertical spacing between trees and shrubs, and remove dead vegetation out to 100 feet (or the property line). Extend this zone farther downhill on slopes.
- 6
Move firewood and propane away. Relocate firewood piles and propane tanks at least 30 feet from the house and trim any branches within 10 feet of the chimney.
- 7
Document it for your insurer. Take dated before-and-after photos and keep contractor invoices so the work counts toward carrier discounts and IBHS Wildfire Prepared Home certification.
Defensible space checklist
The recurring seasonal work, highest-impact first.
Home-hardening upgrades & what they cost
Hardening the structure itself — because most homes ignite from embers, not a wall of flame.
Class A fire-rated roof. Metal, concrete tile, or Class A composition — the largest ember-exposed surface. ~$8,000–22,000 at replacement; eliminates the #1 ignition point and earns carrier discounts.
Ember-resistant vents. 1/16" mesh or intumescent vents (ASTM E2886) on every opening. ~$400–900 retrofit; blocks the embers responsible for most home losses.
Enclosed eaves & soffits. Fiber-cement or noncombustible soffits stop ember accumulation under the roofline. ~$1,000–4,000.
Dual-pane tempered windows. Resist the radiant heat that shatters single-pane glass and lets fire inside. ~$3,000–12,000; metal shutters are a cheaper retrofit.
Noncombustible siding. Fiber cement, stucco, or metal in place of wood within the first several feet. Cost varies by extent.
Class A or composite decking. Replace combustible decks within 5 ft with composite, metal, or masonry. ~$2,000–7,000.
The products that help
Reviewed and rated for wildfire hardening and smoke protection.
Grants, certification & certified contractors
Many states fund this work through grants, rebates, and tax credits, and an IBHS "Wildfire Prepared Home" assessment documents it so it counts toward insurance discounts. Your FireRisk report flags which of your recommended actions are grant-eligible and connects you with a trusted local contractor who can do the work and provide the paperwork carriers want.
Defensible space & home hardening FAQ
How much defensible space do I need?
In most high-hazard areas the standard is 100 feet around structures (or to your property line). It’s managed in zones: Zone 0 (0–5 ft, ember-resistant), Zone 1 (5–30 ft, lean and green), and Zone 2 (30–100 ft, reduced fuel). California’s PRC 4291 makes 100 ft a legal requirement in State Responsibility Areas; check your state and local rules.
What is home hardening vs. defensible space?
Defensible space is the landscaping work around the home (clearing and spacing vegetation). Home hardening is upgrading the structure itself — roof, vents, eaves, windows, siding, deck — so it resists embers and flame. You need both: most homes are lost to embers entering vents or igniting debris against the house, not to a wall of flame.
Does defensible space lower my insurance?
Increasingly, yes. Documented defensible space and home hardening are part of IBHS "Wildfire Prepared Home" certification and most carriers' discount checklists (typically 5–25%), and in many high-risk ZIPs they now determine whether a carrier will write you at all. Keep dated before/after photos and contractor invoices.
Are there grants to pay for it?
Yes. Many states fund defensible space and home hardening through cost-share grants, rebates, and tax credits (Colorado offers a 25% mitigation tax credit, for example). Your FireRisk report flags which of your recommended actions are grant-eligible, and our state fire-insurance pages list the programs.
What’s the highest-impact thing I can do first?
Clear the 0–5 ft Zone 0 ring and retrofit your vents. Together they address the two most common ways homes ignite — embers landing in debris against the house, and embers entering the attic through vents — for a few hundred to a couple thousand dollars.
Free quotes · Trusted local pros
Ready to turn this guide into a done project?
Free quotes from trusted local pros for defensible space, landscaping, and home hardening — plus the documentation your insurer wants to see.