Centennial Valley Volunteer Fire Department

Defensible Space

What can I Do to Protect My House from a Wildfire?

This is a question that we at the Centennial Valley Volunteer Fire Department get ask a lot, but not often enough. Everyone can mitigate the chances of loss to wildfire: first, make sure CVVFD has access to your property; next create an area around your home--that is, create area around your home and other buildings that will prevent a high intensity fire from getting close enough to cause damage.

First thing to do is look at your driveway from the road to your house.  Is it wide enough to bring in a large fire truck?  We need to be able to get a truck, people, and water close to your house.  Do you have your house number clearly posted at end of your driveway?  Do you have a large turn around at your house so we can get a truck turned around easily?  If any of these things are lacking, fix them quickly.  Then you can start working on your defensible space.

Start with your buildings--your house, your garage, shop, sheds, well house, other structures, and your propane tank.  Remove all vegetation five feet away from each.  Replace this vegetation with material that will not burn such as gravel or rock.  Be sure to look under your decks and other structures for burnable materials, like weeds, grass, firewood, and flammable items.  Check all roofs to make sure they are in good repair and are sealed with non-flammable roofing materials.  Make sure you have metal screens on all your roof, eave, attic and crawl space vents.  The screens need to have small enough mesh to keep hot embers from blowing in.

Once you have non-flammable barriers around all structures, begin creating defensible space.  Configure three concentric circles: the first at least 30 to 40 feet around the buildings; the second, at least 60 feet from the buildings and preferable 130 feet away; the third another 100 to 200 feet away from the buildings, for a total of 230 to 330 feet out.  Remove all the dead trees, branches, and brush from these spaces and mow or cut grass and weeds.  When all the dead materials are gone, start thinning the live trees.  For the small circle closest to the house, thin the trees to have at least 12 feet of space between the branches of adjoining trees and limb-up each tree so that no branches are within 10 feet of the ground.

In the second circle repeat the process you used for the smaller circle. Thin the trees so there is at least nine to ten feet of space between the branches of adjoining trees.  Limb-up all the trees that are left so that no branches are within eight to nine feet of the ground.  In the third circle thin out the live trees so they have at least six feet of space between their branches of adjoining trees and limb the remaining trees a least six feet off the ground.

Now you have an area that will allow firefighters to work and take care of embers that will blow in in advance of the main fire.  The thinned  trees will prevent a crown fire (fire up in the tree branches) from getting close to your house.  The fuels will be far enough apart that burning trees will not easily ignite their neighboring trees.  Once the fire has dropped out of the crown, it can be worked by firefighters with hand tools and fire trucks.

For more information on protecting your house, you can also contact Wyoming State Forestry Division, your insurance company, and CVVFD.  CVVFD have a few folks that are specially trained in structure protection.  They can answer questions or maybe even come to visit your place and help develop ideas with you.

The time to do this planning and work is now when there is no fire nearby.  Also, once the defensible space is created, it needs to be maintained.  Trees and brush are constantly growing.  You need to maintain the spacing of trees, remove dead vegetation, and mow grass and weeds  If you follow these basic guidelines, you will significantly decrease the risk of losing your home to wildfire.