Defensible Space

Defensible space guidelines

External Structure Considerations

  • Fire resistant roofing material
  • Enclose with screening or ‘hardyplank’ wooden patios and decks
  • Clean gutters and roof of debris
  • Remove branches which overhang roofs and decks
  • Place gravel or rock around structure for 3 feet
  • Propane tanks at least 50 feet away
  • Address signs clearly visible from the road
  • Place screening over all external piping/vents that enters the house


Surrounding Defensible Space Guidelines

Zone 1 -- from structures to 30 feet out from the eaves per US Forest Service Personnel

  • Remove all debris, slash, needles, leaves, dead branches and trees, etc.
  • Remove all trees with canopies within 15 feet of the structure
  • Prune trees within the space to at least 12 feet above ground
  • Remove tall plants within 3-5 feet of structure
  • Remove all plants directly beneath windows and vents
  • Remove sagebrush and cut grass short
  • Remove branches overhanging driveway
  • Place wood for burning at least 50 feet away and uphill

Zone 2 – extends to at least 100 feet from the structure (see below)

  • Remove all slash, old wood stacks, fallen dead trees
  • Remove standing dead trees
  • Remove branches and ladder fuels to at least 8 feet
  • Selective thinning to place crowns at least 15 feet apart
Note: See Firewise USA  and Colorado State University Extension for the definition of Zone 2 defensible space. It extends to at least 100 feet out from the structure if built on flat ground. If the house is on a hill the defensible space is shorter going uphill and on the sides and longer downhill. For example, if the home is on a 20% slope the minimum space is 90 feet uphill and to the sides and 104 feet downhill.