Separating Your Home From Wildfire – Defensible Space
Most homes lost to wildfire are first ignited by embers and small flames. By decreasing the susceptibility of the home and the immediate area surrounding the home, the chances of your home surviving an ember storm are greatly increased. Work in the Home Ignition Zone is also called creating “defensible space”.
The Home Ignition Zone is an area 100-200 feet from the foundation and includes the home itself, surrounding vegetation, and other structures or attachments like decks, furniture, fences, and outbuildings. Home hardening is an important component of the Home Ignition Zone.
Defensible space means a healthy, well maintained landscape. Native plants and trees, and healthy habitat for birds, animals, and pollinators should all be part of your defensible space plan. Creating defensible space does not mean you need a ring of bare dirt around your home. Through proper planning and routine maintenance, you can have both a beautiful landscape and a fire-resistant home.
Maintaining adequate defensible space also means there is a safe area for firefighting crews to operate during a wildfire event. Having firefighting resources on your property during a wildfire event greatly increases the chances your home will survive without major damage. Firefighters are unlikely to stay and defend your home if you have not taken proactive actions to create the defensible space standards listed below and providing first responders a safe working environment.
Defensible space can be broken up into multiple zones, each requiring a different level of planning and maintenance. The zones are often defined differently, but the principles remain the same.
Defensible space is required by law in the California Fire Code. Check with your local fire department for any additional defensible space or weed abatement ordinances.
Zone 0 (0 – 5 feet)
Zone Zero, sometimes referred to as the “Immediate Zone” is the area nearest your house and includes the surfaces of the structure itself, plants, decks, and outdoor furniture. Ideally, there should be zero combustibles in this zone. This area is the most vulnerable and should be more aggressively maintained to be fire resistant.
In this zone, you should:
- Remove combustible outdoor furniture. Replace with metal or non-combustible varieties.
- Replace natural fiber doormats with heavy rubber or metal grates.
- Remove or relocate all combustible materials including garbage, wood piles, and patio accessories.
- Clean all fallen leaves and needles.
- No vegetation is recommended within 5’ of any structure.
- Remove tree limbs that extend into this zone. Fire prone tree varieties should be removed if they extend into this zone.
- Do not store firewood or lumber in this zone. They should be moved to at least 30’ from any structure.
- Hardscaping such as stone or gravel is strongly recommended around the base of all structures and may be required in California soon. We have found many insurance companies are already making this a requirement to maintain coverage.
Zone 1 (5 - 30 feet)
Zone 1, sometimes referred to as the “Intermediate Zone” extends from your house’s exterior walls to a distance of 30’.
In this (“Lean, Green, and Clean”) zone, you should:
- Remove all dead grasses, weeds, plants, and foliage.
- Remove all fallen leaves, needles, twigs, bark, cones, and small branches.
- Use only compost or heavy bark mulch to maintain soil structure or for erosion control.
- Choose only fire-resistant plants and keep them healthy and well irrigated.
- Provide spacing between shrubs, at least 2 times the height of the mature plant. This spacing should increase on steeper slopes.
- Trim trees to remove “ladder fuels” or branches which are lower than 6’ to the ground.
- Remove branches that overhang your roof or within 10’ of chimneys.
- Move firewood and lumber out of Zone 1 or cover them with a fire-resistant material.
- Remove combustible material around and under decks and awnings.
- Clear vegetation around fences, sheds, outdoor furniture, play structures.
- Outbuildings and LPG storage tanks should have at least 10’ of clearance.
- This zone should receive regular maintenance, focusing on the area closest to the structures and extending out.
Zone 2 (30 – 100’)
Zone 2, sometimes referred to as the “Extended Zone”, extends from 30’ to at least 100’. More defensible space may be required depending on site specific characteristics such as topography, building construction, and vegetation types or within certain areas of Santa Barbara County.
In this zone, you should:
- Cut or mow annual grasses down to a maximum height of 4 inches.
- Create horizontal spacing between shrubs and trees.
- Limit “ladder fuels” by creating vertical spacing between grass, shrubs, and trees.
- Remove fallen leaves, needles, twigs, bark, cones, and small branches. This removal is not required to be as aggressive as in the other zones and may need to be balanced with erosion concerns on steeper slopes.
- Remove all piles of dead vegetation.
Zone 3 (0 – 10’ along access routes)
Zone 3, the “access zone”, extends from 0 feet to at least 10 feet horizontally from the edge of roads and driveways, and includes 14 feet of overhead clearance.
Property owners are responsible for vegetation adjacent to roads and driveways. Properly maintained access routes are critical for emergency evacuations and first responder access.
In this zone, you should:
- Clear vegetation 14 feet overhead and 10 feet from sides of roads and driveways in the same manner as Zone 1.
- Maintain at least 12 feet of unobstructed pavement for passage of vehicles.
- Within this zone, plantings should be fire resistant and must not extend into the roadway.
- Create vertical spacing between shrubs and lower tree limbs.
- Cut all grasses to ground level.
- Address numbers must be clearly visible from the road and have at least 4-inch numbers on a contrasting background. Reflective or lighted numbers work best.
- Emergency access for first responders are required for entrances with locked gates. Knox Box systems can be ordered online by referencing your specific fire department. If needed, contact your local fire department to find out more information on emergency key requirements.
Zone 4 (100 feet and out)
Local laws usually do not require you to create defensible space on property you do not own. However, the most effective solution is a cooperative approach to overall community fire safety between neighbors.
Remember the most important zone is the one closest to your structure. If you have taken all the steps outlined above and worked to “harden” your home, neighboring properties will usually present minimal risk.
Work with neighbors, land managers, and your local fire department to reduce fuel on nearby properties or create community fuel breaks. The Firewise USA program is designed to help with these efforts.
Reference your specific Community Wildfire Protection Plan for community specific recommendations and best management practices.
Contact your local fire department and request a “Defensible Space Survey”. There are resources to assist you in identifying the specific work which should be done on your individual property.