A new exterior should feel right for your home. In parts of Colorado, it also needs to meet wildfire construction requirements. Before choosing siding or ordering windows, start with your address and the work you plan to do.
Colorado’s wildfire rules do not apply identically to every home. Your local building or fire authority can confirm whether your property falls within a regulated area and which requirements apply to your project.
What has changed in Colorado?
The state adopted its Wildfire Resiliency Code in 2025. Applicable local governments were required to adopt a code by April 1, 2026, with enforcement beginning July 1, 2026. Some communities adopted requirements earlier. The rules address new construction and certain exterior alterations in designated wildland-urban-interface areas, where homes and vegetation meet. They are not a blanket instruction to replace every existing exterior.
See the state’s local-government guidance and confirm the current adopted rules with your jurisdiction.
Project size can change the requirements
Replacing a few damaged boards and residing a whole house may be treated differently. For example, the adopted Larimer County code addresses replacement affecting 25% or more of the total exterior wall area, with broader wall and immediate-zone requirements and exceptions. That county example should not be applied automatically to a home inside a city with its own code.
Ask your local authority how it measures the proposed work, which exceptions apply, and what documentation it needs before products are ordered. Larimer County’s adopted code shows why the actual local text matters.
Look at the wall system, not only the siding label
Noncombustible siding can be part of a wildfire-conscious exterior. James Hardie identifies its fiber cement siding as noncombustible under ASTM E136. That material property does not make a house fireproof or establish compliance for every wall assembly. Installation details and other exterior components still matter.
If you are comparing siding products, ask which documented assembly meets the requirements for your property. A general fire-rating claim is not a substitute for approval of the proposed system. Read James Hardie’s Colorado guidance for its product perspective.
Window requirements need a closer look, too
Do not assume that an energy-efficient window automatically meets wildfire requirements. Local rules may specify glazing or fire-performance options. Larimer’s adopted code includes tempered glass, multilayered glazing, glass block, and a minimum 20-minute fire-protection-rating option. The applicable project scope and local interpretation still need to be checked.
Bring the questions to your estimate
Have your address, photos of the exterior, and a description of the work ready. Ask who will confirm permit requirements and how product documentation will be included in the project. That conversation is more useful than choosing a product first and checking the rules later.
Window & Siding Outlet can help you compare exterior options for your home. Request a free project estimate to start with our local team.
Reviewed September 17, 2026. Requirements depend on the adopted local code, property designation, and project scope. Confirm them with the authority responsible for your address.