The immediate zone around a house— the first 0–5 feet from the structure—is the most critical area for defensible spacing and should be void of any flammable materials. The exterior of a structure, including the roof, gutters, eaves, flashing and window panes, are cleaned and/or replaced to prevent embers from igniting against another fuel source. Vents and openings have ember-resistant screening. Hard surfaces: e.g. gravel, concrete, or masonry, replace materials such as mulch and combustible ground-covers. Exterior siding, decks, and porches are made or treated with ignition-resistant materials.

This zone slows advancing fire and reduces radiant heat before it reaches your home. To properly mitigate, tree branches are removed to eliminate ladder fuels. Proper spacing between trees and shrubs breaks up continuous vegetation and prevents rapid spread. Pruned large tree branches, 6–10 feet from the ground maintain a safe distance for ground fire not to climb into the canopy. To avoid high amounts of flash fuel, grass is mowed to 4 inches or less and all dead plant material is removed. Firewood and combustible materials are stored at least 30 feet from structures.

Zone 3 is your outermost firebreak — the extended zone that interrupts fire's path and keeps flames low and on the ground before they ever reach your home. This is generally where the woods or other wild areas begin, and where excess fuel such as downed trees, heavy brush, and dense conifer stands should be reduced. Dead vegetation, debris accumulation, and small conifers growing between mature trees are removed. At 30–60 feet from the home, tree canopies are spaced out at least 12 feet apart. At 60–100 feet, the canopy is spaced out to a minimum 6 feet between the canopy tops. Where your property line falls short of 100 feet, neighbors should be worked with to extend the fuel break cooperatively across boundaries. On steep slopes, fuel reduction is balanced with erosion control.