Defensible space is the managed buffer around a structure designed to slow wildfire spread and give firefighters a place to defend the home. California, Oregon, Colorado, Idaho, Montana, Utah, and Nevada all have formal defensible-space standards, and most wildfire-exposed carriers now require Zone 0 compliance as a condition of renewal.
Defensible-space zones — the standard
| Zone | Distance | Goal | Required Actions |
|---|---|---|---|
| Zone 0 — Ember-resistant | 0–5 ft from structure | Stop ember ignition at the wall | No mulch, no plants against siding, no firewood, gravel/stone hardscape only |
| Zone 1 — Lean & green | 5–30 ft | Eliminate continuous fuel | Mow to 4", tree crowns ≥10 ft apart, branches limbed 6–10 ft up, irrigated |
| Zone 2 — Reduced fuel | 30–100 ft | Slow fire intensity | Tree spacing 10–20 ft, remove ladder fuels & deadwood, thin shrubs |
| Extended Zone (slopes >20%) | 100–200 ft | Account for upslope acceleration | Extend Zone 2 standards downhill |
Hardening + defensible space scoring (used by insurers)
| Item Inspected | Pass Standard | Carrier Impact |
|---|---|---|
| Roof covering | Class A (metal, tile, asphalt) | Hard requirement |
| Gutters | Metal, cleaned, or gutter guards | Required |
| Vents | 1/8" ember-resistant mesh | Required |
| Decks | Ignition-resistant or non-combustible | Discount or requirement |
| Siding | Stucco, fiber cement, metal | Discount |
| Windows | Dual-pane, tempered outer pane | Discount |
| Fencing within 5 ft of house | Non-combustible section | Increasingly required |
| Address visible from road, 50 ft driveway width | For fire apparatus access | Underwriting condition |
Photograph completed work each spring and keep receipts — Agents can submit a mitigation packet to the underwriter to either secure coverage in admitted markets or move a policy off a FAIR Plan.