Tierrasanta - Fire Safe Council
T-FSC

Slope Considerations

Fire Safe Home

minimum dimensions for defensible space

chart showing minimium dimensions for defensible space
 If your home is situated on a 20 percent slope, the minimum defensible space dimensions would be 90 feet uphill and to the sides of the home and 104 feet downhill from the home.

Excerpt from: Creating Wildfire-Defensible Space For Your Home and Property
 Cooperative Extension, College of Agriculture & Life Sciences, The University of Arizona
 

 

DEFENSIBLE SPACE DISTANCES

 

DISTANCE FROM HOUSE

PERCENT SLOPE

UPHILL

SIDES

DOWNHILL

Level to 20%

100 ft.

100 ft.

100 ft.

21% to 40%

150 ft.

150 ft.

200 ft.

41% to 60%

200 ft.

200 ft.

400 ft.

 

Defensible space is an area around your home which is planted and maintained to provide a buffer zone against and to provide firefighters access and space to protect your home.  The width of needed defensible space depends on the steepness of the slope and the type of vegetation present adjacent to your home.  The steeper the slope and the heavier the vegetation, grass vs. bush vs. trees, the wider the defensible space needed.  Under optimum conditions the minimum width should not be less than 30 feet.  In some extreme instances this width could be as much as 400 feet or more.  Many jurisdictions require a minimum defensible space of 100 feet in high fire risk areas.

Excerpt from: COMMITTEE FOR FIRESAFE DWELLINGS