Defensible Space
& Home Hardening

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Creating Defensible Space
What is a defensible space? Defensible space is the area between a house and an oncoming wildfire where the vegetation has been modified to reduce the wildfire threat and to provide an opportunity for firefighters to potentially defend the house.

Defensible space is essential to improve your home's chances of surviving a wildfire. It's the buffer you create between your home and the flammable vegetation, like trees, grass and shrubs, around your home.

To have Evergreen Fire/Rescue Mitigation personnel come do a site visit to your home, call 720/649-1473. 

Defensible Space Zones
The following Defensible Space Recommendations are to be reviewed and addressed seasonally and/or as needed by homeowners.
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0’-5’ Zone – Non-Combustible Zone
☐  Remove all flammable vegetation, including shrubs, slash, mulch, dead vegetation, pine needle, ground debris
☐  Remove all firewood and/or other combustible materials
☐  Prune tree branches within a 10’ area surrounding all structures
☐  Remove all debris, such as pine needles from roof and gutters

5’-30’ Zone – Lean, Clean and Green Zone
☐  Mow grasses to 4” or less
☐  Remove trees to create 10’+ spacing between individual canopies
☐  Prune trees to a height of 6-10’ above the ground or 1/3 of the tree’s total height whichever is less
☐  Remove ladder fuels
☐  Remove any dead, stressed, diseased or dying vegetation, including limbing dead branches off trees and shrubs
☐  Remove large accumulations of surface fuels, such as logs, branches, slash, and mulch
☐  Space shrubs at 2 ½ times their mature height and minimum 10’ from tree branches
☐  Small isolated groups of trees can remain, space accordingly

30’-100’ Zone – Wildland Fuel Reduction Zone
☐  Remove trees to create 6-12’ spacing between canopies
☐  Remove ladder fuels
☐  Remove any dead, stressed, diseased or dying vegetation, including limbing dead branches off trees and shrubs
☐  Remove large accumulations of surface fuels, such as logs, branches, slash, and mulch
☐  Propane tanks and firewood should be 30’+ away from home and clear all vegetation 10’ around

For additional guidelines to creating defensible space (click for CSFS HIZ Guidelines PDF)

Not all homes are built the same. The materials, design and construction assembly of a home plays a particularly large role in the home’s likelihood of surviving a wildfire. The practice of reducing structural ignitability is commonly called “home hardening.” In addition to creating defensible space around your home, “home hardening” your structure from wildfire is also a proactive way to reduce the risk of loss.

Considerations to Reduce Structural Ignitability
  • Ensure the roof has a Class A fire rating
  • Screen attic, roof, eaves and foundation vent with 1/8 inch metal mesh
  • Screen or wall-in stilt foundations and decks with 1/8 inch metal mesh
  • Use tempered glass for windows, two or more panes are recommended
  • Create 6” of vertical clearance between the ground and home siding
  • Replace combustible fencing or gates, at least within 5 feet of the home with metal fencing
  • Use ignition-resistant siding on exterior walls
  • Seal, cover or add flashing to any gaps or cracks in siding or around framing
  • Ensure that the chimney has a proper spark arrestor

Most homes do not ignite from direct contact with flames. 90% of homes are destroyed indirectly by wind-borne embers carried ahead of a wildfire.

Embers can glow as hot as the fire from which they arise, and are light enough to be carried by the wind for long distances without being extinguished. Embers are the primary reason properties go up in flames whenever a wildfire is nearby. Taking necessary measures to prepare your home can help increase its chance of surviving wildfire. Click here to learn what you can do to Harden Your Home.

During a wildfire everything on your property – landscaping, cars and the home itself – has the potential to become fuel for the fire. Fire-resistant landscaping is one step property owners can take to decrease these hazards. Click here to learn more about fire-resistant landscaping.