2025 Colorado Wildfire Resiliency Code

The following outlines a state-mandated code update in Colorado focusing on wildfire resiliency. The Colorado Wildfire Resiliency Code is a draft document detailing regulations for construction and property maintenance in wildland-urban interface areas, aiming to safeguard life and property from wildfires. It introduces two classes of structure hardening (Class 1 and Class 2) based on fire intensity classification (low, moderate, and high), outlining specific requirements for building materials, defensible space, and site features. The code also establishes an administrative framework for enforcement, permits, inspections, and an appeals process for governing bodies, with a three-year property evaluation requirement to ensure ongoing compliance.

The "2025 Colorado Wildfire Resiliency Code" (CWRC) Version 1.0, effective June 1, 2025, is a new comprehensive set of regulations designed to enhance life safety and property protection in Colorado's Wildland-Urban Interface (WUI) areas. Its core purpose is to mitigate the risks associated with wildland fires, specifically by preventing fire from spreading into structures and preventing structure fires from spreading to wildland fuels. The code is designed with a tiered approach, meaning the requirements will vary based on the level of wildfire hazard present in a specific area, and it supplements existing building and fire codes.

Summary

1. The CWRC Applies to the following Areas and Activities

• Wildland-Urban Interface (WUI) Areas: The code applies to areas where human development meets or intermingles with wildland or vegetative fuels, as designated and mapped by the local "authority having jurisdiction" (AHJ). These official maps, which also show Fire Intensity Classifications, will be publicly available online and at local government offices.

• New Construction & Major Work: It primarily applies to the construction, alteration, movement, repair, maintenance, and use of any building or structure containing occupiable and/or habitable space within these designated WUI areas.

• Retroactive Requirements: While generally for new conditions, certain provisions are retroactive. This means they apply to existing structures for:

  • Roof covering replacement if 25% or more of the surface area is being replaced.

  • Ongoing maintenance of buildings, structures, and defensible space in conformance with the code edition installed.

• Additions & Alterations:

  • Minor additions or alterations that do not increase the structure's footprint by 500 square feet or more are generally permitted without requiring the entire existing structure to comply.

  • However, if an addition or alteration increases the footprint by 500 square feet or greater, that work must conform to new construction standards.

• Permit Exemptions (but not compliance exemptions): Certain minor works, like interior alterations, small additions (under 500 sq ft footprint), painting, or minor exterior repairs (less than 25% of surface area), are exempt from needing a permit but must still comply with the code's provisions. Small detached accessory structures (under 120 sq ft, 10 feet from occupiable structures) and certain agricultural structures are also generally exempt from permits.

• Historic Structures: Variances may be issued for historic structures to preserve their character if they meet specific historic designations.

2. Identifying Wildfire Hazards

• Local authorities (AHJs) will designate WUI areas and identify specific Fire Intensity Classifications on official maps. These classifications are based on factors like vegetative fuels, topography, local weather patterns, and fire behavior modeling data.

• Three Fire Intensity Classifications:

  • Low Fire Intensity: Characterized by light to medium fuels, flame lengths less than two feet, low rate of spread, and are typically suppressible by ground crews.

  • Moderate Fire Intensity: Involves moderate to heavy fuels, flame lengths up to eight feet, moderate to high rates of spread, and is challenging for ground crews without support.

  • High Fire Intensity: Features heavy, continuous fuel loads, steep slopes, flame lengths that can exceed 30 feet, and are typically very difficult to suppress directly.

• Ground-Truthing: Property owners can request a "ground-truthing review" to verify that the mapped classification accurately reflects current, site-specific conditions on and around their parcel.

3. Key Requirements for Structure Hardening and Defensible Space

The code sets tiered requirements for exterior design and construction, as well as site-level mitigation, based on the identified Fire Intensity Classification.

• Structure Hardening (Building Materials & Construction):

  • General Materials: Building materials must be noncombustible, fire-retardant-treated wood (labeled for exterior use), or ignition-resistant materials.

  • For Low Fire Intensity Areas (Class 1):

    • Roofing must be Class A rated.

    • Gutters and downspouts must be noncombustible.

    • Ventilation openings (e.g., in attics, crawl spaces) must be covered with listed vents or noncombustible corrosion-resistant mesh with openings not to exceed ⅛-inch to resist ember and flame intrusion.

  • For Moderate or High Fire Intensity Areas (Class 2): All Class 1 requirements apply, plus additional measures:

    • Eaves and soffits must be protected on the underside by noncombustible, ignition-resistant, or 1-hour fire-resistance-rated materials.

    • Exterior walls must meet specific fire-resistance ratings or be constructed of approved noncombustible, heavy timber, fire-retardant treated wood, or ignition-resistant materials.

    • Exterior wall coverings are limited to noncombustible, fire-retardant-treated wood, or ignition-resistant materials (vinyl siding is allowed only if the underlying wall assembly meets specific fire-resistance ratings).

    • Exterior glazing (windows, glazed doors, skylights) must be tempered glass, multilayered panels, glass block, or have a fire protection rating of at least 20 minutes.

    • Exterior doors must be noncombustible, solid core wood at least 1¾ inches thick, or have a fire protection rating of at least 20 minutes.

    • Gaps around vehicle access doors (like garage doors) must not exceed ⅛ inch to resist ember intrusion.

• Defensible Space (Home Ignition Zone - HIZ): The code defines three zones around a structure with specific mitigation requirements. The CWRC provisions take precedence over other guides in case of conflict.

  • Structure Ignition Zone 1 (0-5 feet): The Immediate Zone (Applies to Class 1 & 2)

    • Objective: To reduce or eliminate ember ignition and direct flame contact with the structure.

    • Materials: Primarily noncombustible, hard surface materials like rock, gravel, or concrete.

    • Plantings: Removal of all plantings including shrubs, slash, combustible mulch, and other woody debris, with an exception for ignition-resistant vegetation from an approved list.

    • Trees: No planting of new trees. Existing mature trees must have crowns pruned to maintain a 10-foot clearance from any structure. Branches must be pruned to 6-10 feet from the ground or one-third of the tree's height, whichever is less.

  • Structure Ignition Zone 2 (5-30 feet): The Intermediate Zone (Applies to Class 2)

    • Objective: To give an approaching fire less fuel and reduce its intensity.

    • Fuel Management: Hazardous dead plant material must be removed, and large accumulations of surface fuels should be avoided.

    • Trees & Shrubs: Tree crowns must be spaced to promote fuel discontinuity and maintain 10-foot clearance from structures. Shrub groups must be spaced to prevent structure ignition and be at least 10 feet from tree branches.

  • Structure Ignition Zone 3 (30-100 feet): The Expanded Zone (Applies to Class 2)

    • Objective: To focus on mitigation that keeps fire on the ground.

    • Tree Spacing: Tree crowns within this zone must be spaced at a minimum of 6-10 feet.

• Additional Site Requirements (Applies to Class 1 & 2):

  • Site Signage: Requirements for marking access roads/driveways, fire protection equipment, and posting visible address markers.

  • Retaining Walls: Must be noncombustible or ignition-resistant if within 8 feet of a regulated structure or integral to its support/egress.

  • Fencing: Fences within 8 feet of a regulated structure (or to the property line if closer) must be noncombustible or ignition-resistant, though vinyl fencing may be an exception.

4. Administering and Enforcing the Code

• Code Official (AHJ): The local "Code Official" is responsible for interpreting and enforcing the code. They have broad powers including approving alternative materials, issuing permits, conducting inspections, and issuing corrective orders.

• Permits: A permit is required for most construction, alteration, and repair work unless specifically exempted. Detailed construction documents, including site plans that identify the fire intensity classification and defensible space plans, must be submitted for review and approval.

• Inspections: Work requiring a permit is subject to inspection by the Code Official, and work cannot proceed past certain stages without their approval.

• Enforcement: The Code Official can issue corrective orders and notices for violations. Failure to comply can result in prosecution, fines, and abatement action (requiring repair, rehabilitation, demolition, or removal of unsafe conditions). Buildings or structures posing a fire hazard or danger to life/property are deemed "unsafe conditions".

• Fees: Local AHJs have the authority to establish fees for permits and violation penalties.

This code aims to create safer communities by implementing specific standards for building in and managing landscapes within Colorado's WUI areas, helping to reduce the risk from wildfires.

Public Engagement

You can engage with this project using the Questions and Comments tabs below. This page will be open to feedback and questions until the date of the City Council, 2nd reading Public Hearing. We will provide more about this hearing on this webpage before the meeting.

The project timeline on this page provides an overview of the next steps in the process as Broomfield considers the approval of this proposed ordinance.

Next Steps

We will be conducting a local mapping pilot project this fall, including on-the-ground field verification performed by an experienced GIS mapping consultant with expertise in spatial data accuracy and field-based validation. The pilot area is located between 144th Ave. and 152nd Ave., and between Zuni Street and Lowell Blvd.

A study session with City Council is planned for early 2026 to evaluate the results and determine next steps. A second community meeting will also be held around the same time to share findings and gather additional feedback.