Defensible space zones are rings of managed ground around a house that keep embers and flames from finding fuel next to it. Colorado uses three: Zone 1 from 0 to 5 feet, Zone 2 from 5 to 30 feet, and Zone 3 from 30 to 100 feet. The first 5 feet, often called the immediate or noncombustible zone, matters most, because it is where embers pile up against the walls. Under the 2025 Colorado Wildfire Resiliency Code, every mapped parcel must keep that zone noncombustible, and moderate and high parcels also manage Zones 2 and 3. This page is general information; Integrity Roofing and Painting is a roofer, not a landscaper or mitigation contractor.
On this page: The three zones · Zone 1 · Fences and sheds · Zones 2 and 3 · Where to start
The three zones at a glance
The Colorado State Forest Service, the state agency the code points to for site guidance, describes the zones this way, and NFPA’s Firewise program uses nearly the same rings:
| Zone | Distance | Goal | Code applies to |
|---|---|---|---|
| Zone 1, immediate | 0 to 5 ft | No ember ignition or flame contact at the walls | All mapped parcels (Class 1 and 2) |
| Zone 2, intermediate | 5 to 30 ft | Less fuel, lower flame intensity near the house | Moderate and high parcels (Class 2) |
| Zone 3, expanded | 30 to 100 ft | Keep fire on the ground | Moderate and high parcels (Class 2) |
CSFS notes Zone 3 extends 100 feet on fairly flat ground; NFPA says the extended zone can reach 200 feet. Steeper lots need more. CSFS also advises creating zones around every building, including detached garages and barns, and starting with the house before working outward.
Zone 1: the first 5 feet
Section 502.1 of the state code sets the rules for the immediate zone:
- Surfaces: noncombustible, hard materials such as rock, gravel, sand, concrete, bare earth or pavers.
- Plants: remove shrubs, slash, combustible mulch and woody debris. The local authority may allow ignition-resistant plants from an approved list at least as strict as the CSFS list.
- Trees: no new trees. Mature trees at least 10 inches in diameter at 4.5 feet above the ground may stay. Crowns within 10 feet of the house are pruned back to 10 feet of clearance, and lower branches are pruned to 6 to 10 feet up or one-third of tree height, whichever is less.
IBHS goes further in its Wildfire Prepared Home program, which is available in Colorado: the 0 to 5 foot zone around the home and any attached deck must hold only noncombustible materials, with no grass, artificial turf, wood mulch, or wood or vinyl fencing. Its 2025 Zone 0 tests showed why plants are a problem even when watered.
Two places where roofing and Zone 1 meet: downspouts that empty into bark mulch, and roof debris that slides off into planting beds. Our gutters and debris guide covers both.
Fences, retaining walls and sheds
- Fences (502.4.1). Fencing within 8 feet of the house, or to the property line if closer, must be noncombustible or ignition-resistant, with an exception that may allow vinyl. NIST ran 187 fire experiments on fences and mulch. Two privacy fences 18 inches apart on mulch were fully engulfed in under four minutes, and flames ran along mulch at fence bases.
- Retaining walls (502.3.1). The same 8-foot rule applies, plus any retaining wall that supports the house or its exit path.
- Sheds. NIST measured flame reach of about 10 feet for sheds under 26 square feet and about 15 feet for sheds up to 64 square feet. The state code exempts sheds up to 120 square feet that sit at least 10 feet from the house.
Zones 2 and 3
On moderate and high parcels, section 503 adds:
- Zone 2, 5 to 30 feet: remove dead plant material, avoid piles of logs, slash and mulch, keep tree crowns 10 feet from the house, space tree crowns and shrub groups to break up fuel, and keep shrubs at least 10 feet from the edge of tree branches.
- Zone 3, 30 to 100 feet: space tree crowns at least 6 to 10 feet apart.
NFPA’s Firewise guidance for these rings adds practical targets, such as mowing grass to 4 inches in the intermediate zone and wider canopy spacing closer to the house. CSFS says the state has offered a wildfire mitigation income tax credit for tax years 2023 through 2027; confirm current rules with the Colorado Department of Revenue before counting on it.
Where to start
- Clear the first 5 feet, starting with the house itself.
- Clean the roof and gutters, and screen vents. See our ember-resistant vents guide.
- Fix where fences and decks touch the house.
- Work outward to Zones 2 and 3, ideally with advice from your local CSFS field office or fire district.
If you are re-siding, the code pulls Zone 1 into the job; see our siding and decks guide and the Colorado Wildfire Resiliency Code guide. The full checklist is in our wildfire home hardening guide.
The roof part of the plan
Integrity Roofing and Painting is veteran-owned, family-run since 1990, and an Owens Corning Platinum Preferred contractor with 650+ Google reviews. We do not do landscaping or fuel reduction, but the roof, valleys, gutters and vents are our work, from Black Forest to Golden. Call (719) 488-2800 for a free Colorado Springs inspection, or (303) 209-0152 for a free Denver inspection.
Our printable wildfire season home checklist puts the yearly Zone 1 cleanup on one page.
Sources: 2025 Colorado Wildfire Resiliency Code, chapter 5 (DFPC); Colorado State Forest Service, Protect your home and property; Colorado State Forest Service, Home Ignition Zone guide; NFPA, Preparing homes for wildfire; IBHS, Vegetation in Zone 0; IBHS, Wildfire Prepared Home: About; NIST, fences and mulch beds study (2022); NIST, sheds in wildfire zones (2023).
