Fire-Rated Windows & Siding
CWRC Compliance for Northern Colorado Homes
Colorado's new Wildfire Resiliency Code requires fire-rated windows, tempered glass, and ignition-resistant siding for homes in WUI zones. Window & Siding Outlet has the products and 30+ years of expertise to get your home compliant
What Is the Colorado Wildfire Resiliency Code?
Effective July 1, 2025, Colorado adopted the Colorado Wildfire Resiliency Code (CWRC) — a statewide building standard for homes and structures in designated Wildland-Urban Interface (WUI) areas. Local jurisdictions must adopt the code by April 1, 2026, with full enforcement beginning July 1, 2026.
The code introduces two tiers of requirements based on fire intensity. Class 1 (low fire intensity) focuses on roofing, gutters, and vents. Class 2 (moderate to high) adds requirements for exterior walls, windows, doors, decking, eaves, and more.
This isn't just for new construction. The CWRC can also be triggered when remodeling or repairing existing homes — particularly when replacing roofing or siding. Understanding the thresholds below is critical before you start your next project.
COMPLIANCE TRIGGER
25% Siding Replacement Rule
If you replace 25% or more of your home's exterior wall surface, the CWRC requires the entire exterior to meet ignition-resistant or noncombustible standards.
COMPLIANCE TRIGGER
25% Roofing Replacement Rule
Replacing 25% or more of your roof covering triggers a requirement to replace the entire roof with a Class A fire-rated assembly.
COMPLIANCE TRIGGER
500 Sq. Ft. Addition Rule
Any addition that increases your home's footprint by 500 sq. ft. or more means the entire structure must comply with the CWRC.
Our CWRC-Compliant Products & Services
We carry fire-rated, ignition-resistant products from trusted manufacturers — installed by our company-certified crews.
Fire-Rated Windows
Class 2 zones require tempered glass, multilayered glazed panels, or windows with a 20-minute fire protection rating. We install Milgard, ProVia, and Simonton windows that meet or exceed these standards.
Ignition-Resistant Siding
Exterior walls must use noncombustible, fire-retardant-treated, or ignition-resistant materials. Our fiber cement, engineered wood, and qualifying vinyl siding systems keep your home protected and code-ready.
Fire-Rated Doors
Exterior doors require noncombustible construction, solid core wood (1¾" minimum), or a 20-minute fire rating. We supply and install patio doors, French doors, and entry doors that meet the CWRC.
Full CWRC Compliance Checklist
Here's what moderate and high fire intensity zones (Class 2) require:
✓ Class A fire-rated roof assemblies
✓ Tempered glass or 20-min rated windows
✓ Ignition-resistant or noncombustible siding
✓ Ember-resistant vents (⅛" mesh)
✓ Protected eaves and soffits
✓ Solid core or fire-rated exterior doors
✓ Noncombustible gutters & downspouts
✓ 5-foot noncombustible immediate zone
✓ Fire-rated decking materials
✓ Underfloor enclosure to ground
CWRC-Compliant Installations Across Northern Colorado
CWRC-Compliant Installations Across Northern Colorado
Wildfire Resiliency Code FAQ
Does the CWRC apply to my existing home?
It depends. Existing homes don't need to retroactively comply unless you trigger one of the code thresholds: replacing 25% or more of your siding or roofing, or adding 500+ square feet to your footprint. If triggered, the entire wall or roof system must meet the new standards.
How do I know if my home is in a WUI zone?
The state has published a WUI map that classifies areas by fire intensity (Low, Moderate, High). You can check the 2025 Colorado Wildfire Resiliency Code Map, or contact your local building department. During your free estimate, we can help you determine your classification.
What kind of windows meet the CWRC?
In moderate and high fire intensity zones (Class 2), exterior windows must be tempered glass, multilayered glazed panels, glass block, or have a fire protection rating of at least 20 minutes. Many of our Milgard, ProVia, and Simonton window lines meet these requirements.
What siding materials are CWRC-compliant?
The code accepts noncombustible materials (like James Hardi), fire-retardant-treated wood, and ignition-resistant building materials. Vinyl siding is permitted as an exterior covering only when installed over a qualifying 1-hour fire-rated or noncombustible wall assembly. We'll help you pick the right system for your home and budget.
When does the code take effect?
The CWRC was adopted at the state level on July 1, 2025. Local jurisdictions are required to adopt the code by April 1, 2026, with enforcement beginning by July 1, 2026. Some jurisdictions like Loveland already have WUI-related codes in place.
Will compliant products cost significantly more?
Not necessarily. Many of the products we already install — tempered glass windows, fiber cement siding, solid-core doors — meet or exceed CWRC requirements. The incremental cost is often minimal, and we offer financing options to help. Plus, fire-hardened homes may benefit from improved insurance rates.
Don't Wait Until Enforcement Begins
Get ahead of the July 2026 deadline. Schedule a free in-home estimate and we'll walk you through exactly what your home needs to meet the new Colorado Wildfire Resiliency Code.
