Five to thirty feet, and the named species

Structure Ignition Zone 2, the Intermediate Zone, caps mulch depth at four inches, requires firewood piles to sit at least thirty feet from habitable structures unless in a noncombustible or ignition-resistant container, requires shrub groups to be “spaced to prevent structure ignition,” and bars shrubs planted under trees within the drip line.

And it prohibits four species by name: “Juniperus spp. (Juniper species), Thuja occidentalis (American arborvitae), Thuja orientalis (Oriental arborvitae), Quercus gambelii (Gambel oak) are prohibited.”

On slopes of 20% or greater, the Wildfire Mitigation Specialist may require additional tree spacing.

The fencing provision, and why architectural committees should read it first

Section 502.4: “Fencing within 8 feet of the nearest point of a structure regulated by this code or up to the property line when the property line is less than 8 feet away from the structure shall be constructed with noncombustible or ignition-resistant building materials.”

Retaining walls follow the same logic: exposed exteriors must be noncombustible or ignition-resistant when within eight feet of a structure, or up to the property line if closer, or where integral to a structure's support or to egress.

In a Colorado planned community whose design guidelines specify cedar or redwood fencing for uniformity, this is a direct conflict on a Jeffco permit. The code governs the permit. The covenant governs the owner's contract with the association. Neither document mentions the other.

What the code says about the Home Ignition Zone Guide

Section 501.2 pins the reference standard and settles conflicts: “the Wildfire Mitigation Specialist shall refer to the most recent version of the Home Ignition Zone (HIZ) Guide as developed by the Colorado State Forest Service. Where conflicts occur between provisions of this code and the HIZ Guide, the provisions of this code shall govern.”

Structure hardening sits in chapter 4 — roofing, gutters and vents at Class 1; plus exterior walls, eaves, windows, doors and decking at Class 2. Signage requirements in section 502.5 include approved road and driveway signs, clearly identified hydrants and fire protection equipment, and a permanently posted address at each driveway entrance visible from both directions of travel, posted at the beginning of construction and maintained thereafter.

What a board in the WUI overlay should do now

Get the overlay map and find out whether the community is in it, and in which class. The boundary was expanded, so a community that was outside the old WUI may be inside the new one. Class 1 and Class 2 carry different hardening requirements.

Read the community's landscape and fencing standards against Zones 1 and 2 before the next architectural application arrives. Three specific conflicts to look for: a requirement for foundation plantings or living ground cover in the first five feet; an approved-plant list containing juniper, arborvitae or Gambel oak; and a fencing specification calling for wood within eight feet of a structure.

Decide, in writing, how the committee will handle a code-compliant application that the guidelines do not permit. The association's own architectural review rules are the association's to amend; the county code is not. An amended approved-materials list and an approved rock-and-gravel palette for the immediate zone is the low-cost answer, and it can be adopted before a dispute rather than during one.

Note the applicability and retroactivity language. Section 101.4 reaches conditions arising after adoption, conditions not legally in existence at adoption, and conditions the code official finds “constitute a distinct hazard to life or property.” This is not purely prospective.

And know that the association has no standing at the code board. Under current law only a local government's governing body may petition the state Wildfire Resiliency Code Board for a modification. HB26-1334 would have opened that to “a person impacted by the codes and standards” and was postponed indefinitely on April 7, 2026. The route stays closed.

What is coming elsewhere in Colorado

Jefferson County is ahead of its neighbours, not out of step with them. Broomfield has publicly discussed the Colorado Wildfire Resiliency Code with a lead time before adoption, giving boards there roughly a year of warning that a Zone 1 hard-surface requirement is heading for their landscape rules. Douglas County lists its own wildfire resiliency code with a July 1, 2026 date. The City of Boulder adopted the 2024 International Wildland-Urban Interface Code with local amendments applying to permits issued after August 1, 2025. Boulder County divides its unincorporated area into three wildfire zones, requires a three-foot noncombustible band next to exterior walls and under decks, and offers a Wildfire Partners assessment-and-certification route as an alternative compliance path.

The documented mitigation any of that produces now has a second use: from July 1, 2026, HB25-1182 requires Colorado insurers using wildfire risk models to credit community-level mitigation or discount for it, and from October 1, 2026 Division of Insurance Regulation 5-1-28 names county and community-level mitigation certificates of completion among the evidence a carrier must consider. A code compliance record is also an insurance document.