As we face extended droughts and hotter temperatures year after year, the threat of wildfire becomes greater. Perhaps you’ve witnessed it firsthand or been directly impacted, or maybe you’ve just watched it on the news and hoped you’d never have to deal with it. Unfortunately, the stark reality is that more people live in the wildland-urban interface (WUI, pronounced Wooey) than ever before.
If you have a cabin built somewhere in the woods or near an area of high fire danger, you must know how to create a cabin fire barrier, also known as defensible space. There are also many changes that you can consider to make sure your cabin or residence is fire safe.
The Wildland Urban Interface
According to FEMA, “The WUI is the zone of transition between unoccupied land and human development. It is the line, area or zone where structures and other human development meet or intermingle with undeveloped wildland or vegetative fuels.”
If you have a house, cabin, other residence, or property in this zone, you absolutely should be figuring out how to create a cabin fire barrier around your structures. It can take work and planning. Many states, especially those in the West where wildfire is more prevalent, have programs that can help landowners evaluate their wildfire risk and determine steps for making their property more fire safe.
Often, these programs offer free assessments. Many also have grants available to help offset some of the work. Talk to your state fire agency or local fire department to determine what is available in your area.
Almost 90% of the wildfires that occur in the United States are due to humans. Unattended campfires and ones not extinguished completely are the top cause. Others include operating vehicles in dry grass, dragging trailer chains that create sparks, improper use of small-engine equipment such as chain saws or lawnmowers, fireworks, exploding targets, debris burning, and cigarettes.
You should constantly monitor the fire conditions in your area before doing any of these activities. If there are burn restrictions in place, fireworks bans, or other regulations meant to curb the potential for wildfire starts, obey them!
Also, pay attention to the weather and when red flag warnings are issued. A red flag warning is issued by the National Weather Service and means weather conditions could result in extreme fire behavior. These warnings are usually given after dry periods of two weeks or less, low relative humidity, and high temperatures.
Even if you are not in the wildland-urban interface, but there is a risk to your home and property from wildfire, you need to create defensible space or a cabin fire barrier.
Defensible space is the buffer area that you create between your house and buildings and the surrounding forest, grasslands, or other vegetation. A defensible area is designed to slow or stop the spread of fire. If a wildfire burns up to this space, the idea is that it will not have the appropriate fuels to burn further.
The fire pyramid consists of three components: oxygen, fuel, and heat. Removing one of these prevents a fire from continuing to burn. If it doesn’t have fuel to keep burning, then the ability to extinguish it is increased.
Defensible space also gives firefighters a safety zone. This zone makes it easier for them to protect your property. It is not only the responsible thing to do as a property owner, but it also helps keep firefighters safe. Let’s hope that it never has to come to that.
Some states, like California, have laws that dictate the amount of defensible space you need to have.
How to Create a Cabin Fire Barrier
Several things can be done to help create this barrier to protect your cabin or home best.
Start at your home and work outwards to 100 feet or your property line, whichever comes first. Your neighbors need to be doing this work as well. If you’ve done the job and they haven’t, depending on how close they are, all your work could be for nothing. Therefore, people must work together to create fire-safe communities.
Cabin Fire Barrier Zone 0 – Ember Resistant Zone
This zone is 0-5 feet from the building, and science has shown it to be the most important. Embers landing on materials this close can easily ignite, spreading quickly to your cabin or home. That is why the goal of Zone 0 is to clear and remove combustible materials in this area.
Here is some guidance for creating and maintaining an ember resistant zone:
- Use non-combustible materials for landscaping, such as pavers, gravel, and concrete
- Remove all dead and dying vegetation such as weeds, shrubs, grass, leaves, branches, etc. Make sure your gutters are also clean of this debris.
- Remove all branches from within 10 feet of your roof and chimney pipes.
- Keep firewood away from the house.
- Limit combustible materials like patio furniture, planters, and other decorations.
- Consider moving garbage and recycling cans to other areas away from the cabin or house
- Replace combustible fencing with non-combustible materials
- Even consider moving RVs, boats, or other vehicles away from buildings
Cabin Fire Barrier Zone 1 – Lean, Clean, Green
This zone is up to 30 feet from your cabin, buildings, decks, or other structures. Many of the “rules” that apply to Zone 0 also apply to Zone 1.
- Keep firewood out of this zone as well
- Remove all dead vegetation
- Trim trees to keep them at least 10 feet from other trees and 10 feet from your roof and chimney
- Keep all flammable materials such as furniture, planters, decorations, equipment, and vehicles out of this zone
- Prune all combustible shrubs and bushes and create plenty of separation from them and other materials that can quickly burn, including other plants
Cabin Fire Barrier Zone 2 – Reduce Fuel
This zone is 30-100 feet from your cabin, home, outbuildings, patios, or other structures. This is where much of the work involves thinning trees and vegetation and creating space.
- Keep grass mowed to no longer than 4 inches
- Ensure proper vertical and horizontal space between trees and bushes
- Remove leaves, branches, pine needles, and pine cones
- Exposed wood piles should have 10 feet of exposed dirt on all sides
Vertical and Horizontal Fire Barrier Space
As mentioned above, trees, bushes, and shrubs should have adequate clearance, both vertically and horizontally, from each other. Since the goal is to reduce wildfire, spacing is determined by the size of the vegetation and the slope it’s on. Here are some guidelines:
- Remove tree branches at least six feet from the ground
- Allow adequate space between low-lying bushes and the trees above them. A good rule of thumb is to allow three times the bush height between the bush and the tree branches, but don’t hesitate to do more if you feel it wise. For example, a 3-foot shrub growing near a tree should have a minimum of nine feet of space between the shrub and the lowest tree branches
- Shrubs on flat slopes should have a minimum of two shrub lengths between them, and trees should have at least 10 feet
- On a 20-40% slope, this should increase to four times for bushes and 20 feet for trees
- For moderate to steep slopes (greater than 40%), the distance between bushes and shrubs should be six times the size of the bush and 30 feet between trees
Fire Resistant Landscaping – Cabin Fire Perimeter
When planning your landscaping, use fire-resistant materials. If you live in an area with an adequate water supply, green lawns are a great barrier. However, since water scarcity, particularly in the Western United States, is becoming more of a problem, there are plenty of other solutions.
As stated before, gravel, pavers, and concrete are also all viable solutions. Bare dirt and non-combustible mulch are also good alternatives. There is such a thing as fire-resistant plants and shrubs. Try to use these for your landscaping. High-moisture plants are also good, although there is no such thing as a fire-proof plant. Hardwood trees such as cherry and maple are also better than conifers.
Fire Resistant Cabin or House Materials
Your cabin home has exposure to wildfire in three ways: direct flame, radiant heat, and flying embers. Therefore it is critical to use materials that are resistant to these as much as possible. Combined with defensible space and fire-resistant landscaping, your home or cabin stands a much better chance of surviving a wildfire.
Roof – Fire Barrier
The roof of your cabin is the most vulnerable. Wood shingles should be avoided at all costs and replaced with metal, clay, tile, or composition materials. Make sure there are no spaces for embers to get caught.
Clean leaves, pine needles, and other debris from your roof and gutters as they can easily catch on fire from flying embers.
Siding, vents, and windows
Use metal vents and cover all openings with metal mesh.
Use ignition-resistant siding, such as fiber cement, stucco, or even treated wood. Any wood siding, such as shingles, is a bad idea. Eves and soffits should also be non-combustible.
Windows should be double-paned. It is a good idea to have one pane made of tempered gas. Radiant heat can cause windows to shatter, allowing embers in that can start fires inside. Also, think about reducing the number of windows that face areas with lots of vegetation.
Decks, patios, and awnings
Any deck, patio, or awning within 10 feet of the house should be constructed of non-combustible material. Remember to keep decks and the areas below them free of debris and combustible materials. Make sure anything that is in these areas is fire-resistant and doesn’t easily burn.
While it is best to keep your fence away from your house, at the very least, make sure the last five feet are a non-combustible material. This lessens the chance fire will make it to your home.
Tools to Have On-Hand
In addition to all of the above guidelines for creating a cabin fire barrier and a fire-resistant home, there are several things you should have on hand in the event you need to defend your cabin and property from wildfire.
Have multiple water hoses on hand. Also, sprinklers that can quickly wet the area surrounding structures. If you have a pond, pool, stream or other water source nearby, consider a pump to get water from it
Keep tools such as a shovel, rake, and bucket readily available.
Final Thoughts On How To Create A Cabin Fire Barrier
Wildfires threaten millions of properties and people every year. If you live in a wildland-urban interface, your risk increases substantially. With increased drought and hotter temperatures, this is not an issue going away any time soon. Therefore you must take the necessary steps and learn how to create a cabin fire barrier to protect your property. If your building a cabin, consider building a fire barrier from the very beginning.
Additionally, it is critical to work with your neighbors to ensure their properties are also defensible. You can do all the work in the world, but if they have done nothing, the risk to your property is substantial.
But remember, despite all the work you put in, it may still not be enough to save your cabin or house. However, your odds will increase significantly if you put in the time and effort to do this work. Adequate defensible space and a fire-ready home will also allow firefighters the best chance of protecting your property. If you haven’t done the work, there is a higher likelihood they will have to leave your house alone because the danger to themselves is too great.
While there are many benefits of living in areas where wildfires occur, we also take risks. Preparing, taking personal responsibility, and working with your neighbors to create a fire-safe community will benefit everyone in the long run.