CO-Horts Blog

Tuesday, September 20, 2022

Preparing Your Home for Wildfire

 By Mark J. Platten, CSU Extension Director, Teller County

As we've seen with the Marshall Fire, Black Forest Fire, and Waldo Canyon Fire, wildfires can affect urban environments as well as the more rural, forested environments we associate with wildfires. In this blog we'll discuss strategies that can give you the highest likelihood of having your home survive a wildfire, although there are no guarantees.

Defensible Space

Mountain Shadows (Waldo Canyon Fire, June 23, 2012)

Defensible space is the buffer you create between a building on your property and the grass, trees, shrubs, or any wildland area that surround it. This space is needed to slow or stop the spread of wildfire and it helps protect your home from catching fire—either from embers, direct flame contact or radiant heat. Proper defensible space also provides firefighters a safe area to work in, to defend your home. 

It is NOT a guarantee that firefighters will be able to save your house during a wildfire.

Fire Behavior Triangle

Three factors determine wildfire behavior: fuels, weather and topography.

         We cannot alter weather or topography, so we must concentrate on altering fuels.


Home Ignition Zone (HIZ)

Two factors have emerged as the primary determinants of a home’s ability to survive a wildfire:

1. The quality of the defensible space and,

2. A structure’s ignitability.

         The primary goal is to reduce or eliminates fuels and ignition sources within the HIZ.

Building Envelope


The likelihood your home will survive a wildfire is based largely on how your home is built and what materials are used. 


Install or replace your roof with a Class A-rated roof with noncombustible coverings.

Clay and concrete tile are noncombustible and because of their relatively large thermal mass, retard the transfer of heat

Metal shingles and panels are noncombustible, but they readily transfer heat. If they are installed over wood battens, fire-retardant-treated battens should be specified and installed. 


An open overhang. The exposed timber rafters and decking are susceptible to ignition, and embers and hot gases can enter the attic through unprotected vent.


Remove all debris from the roof and gutters to prevent embers from starting a fire. 

Make sure to remove branches that overhang the house.


Exterior wall coverings that are noncombustible or fire-resistant and not susceptible to melting are recommended. 

A minimum fire-resistance rating of one hour.

For the best protection, ensure that exterior wall coverings are noncombustible or fire-resistant and not susceptible to melting.

Concrete, fiber-cement panels or siding, exterior fire-retardant treated wood siding or panels, stucco, masonry, and metal are recommended materials.


Cover exterior attic vents, dryer vents, and under-eave vents with metal wire mesh no larger than 1/8 inch to keep embers out.


Exterior doors are subject to the same types of exposure as exterior walls in a wildfire.


Garage doors are typically made of wood, aluminum, or steel and are insulated or non-insulated.

         The common split-rail or picket fence can become fuel for a wildfire, especially when the fence is old and weather-beaten.

This type of fence can also collect embers and firebrands in a wildfire and act as a horizontal ladder fuel by allowing the fire to travel along the fence toward the main building.


Replace combustible materials with noncombustible or fire-resistant materials.Replace timber railings with railings constructed of fire-resistant materials.

Construct deck skirting around the deck or max 1/8-inch wire mesh.

Don't store combustible items on the deck.  



Double-pane, tempered glass is best.

Install metal screens on all windows.

Plastic skylights can melt.




These are recommendations to give your home the best chance of surviving a wildfire.

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