What the hell is a Spark Arrestor? Do policemen own one? Does it shock you?
First of all, no. And second of all, you’ve come to the right place. Today, in this blog, we will be talking about one of the lesser-known parts of your roofline. They are the most underrated piece in your roofline because they keep your house from burning down, and they keep any foreign object from getting into your chimney.
The Spark Arrestor is known for its importance for fire safety. However, they can also become an entry point for wildlife and pests if they’re not installed correctly and maintained.
Our team at Abra Kadabra has the expertise and knowledge when it comes to Spark Arrestors. We’ve seen so many homes that deal with pests and wildlife coming in through their chimneys, and we’ve installed so many Spark Arrestors. If you deal with this issue in your house, give us a call. But for now, sit back and learn more about this critical piece in your roofline area.
In this article, we’ll explain:
- What a spark arrestor is and why it’s used
- How wildlife manages to get in
- The dangers of ignoring this vulnerability
- And how to prevent unwanted animal guests from invading your chimney
What Is a Spark Arrestor?
A spark arrestor is a metal mesh screen installed at the top of a chimney or flue to prevent sparks from escaping. Its primary purpose is to:
- Prevent embers or sparks from escaping and landing on your roof or nearby trees, especially during fireplace or wood stove use
- Reduce fire risks, particularly in areas prone to wildfires or with lots of dry foliage
- Block debris from falling into the chimney and causing clogs
Spark arrestors are often integrated into chimney caps and are legally required in many parts of the U.S. due to their fire safety benefits.
While these devices do a great job of controlling sparks, they can also inadvertently allow small animals access, especially if they are poorly fitted, damaged, or not wildlife-proof.
How Wildlife Gets In Through Spark Arrestors
Many homeowners assume that if they have a spark arrestor, their chimney is sealed off from pests. Unfortunately, that’s not always the case.
Here are a few common scenarios where wildlife gains access:
1. Loose or Damaged Mesh
The mesh on a spark arrestor is often made of stainless steel or galvanized wire. Over time, weather exposure, rust, or pressure from curious animals can cause the mesh to:
- Pull away from the chimney cap
- Tear or unravel
- Corrode and develop holes
Even a small tear or gap can be an invitation to:
- Squirrels are looking for a warm place to nest
- Birds seeking shelter
- Bats are squeezing through tight openings
- Raccoons, which are incredibly strong and persistent
2. Improper Installation or Sizing
Not all spark arrestors are created equal. Some are installed as an afterthought, without considering the dimensions of the floor, the local wildlife, or the weather conditions.
If the arrestor is:
- Too small or loose
- Installed off-center
- Not securely fastened
3. No Chimney Cap (Only a Spark Arrestor)
Some older chimneys may have only a spark arrestor screen at the flue opening without a full chimney cap. While this may satisfy specific fire codes, it offers little protection from:
- Rain and snow
- Leaves and debris
- And, of course, wildlife intrusion
Raccoons, for example, can easily climb chimneys and reach in through basic mesh to pull it open or rip it aside. Once inside, they may fall into the chimney flue or set up a den directly in the chimney.
4. Nest Building on Top of the Arrestor
Even if the arrestor is intact, birds and squirrels may build nests directly on top of it. Over time, nesting material can:
- Clog the mesh
- Block the exhaust flow
- Increase the risk of smoke backup and carbon monoxide inside your home
- Catch fire from heat or sparks
This is especially common in the spring when animals are looking for secure places to raise their young.
What Happens When Animals Get In?
Once wildlife has accessed the chimney or flue system through a spark arrestor, the consequences can range from annoying to dangerous.
Birds
Birds may fall into the chimney and become trapped, unable to fly out. Some, like chimney swifts, are protected species and cannot legally be removed during nesting season.
Trapped birds often:
- Die in the chimney, causing odors and attracting insects
- Block airflow, leading to dangerous smoke buildup
Squirrels and Raccoons
These animals often nest in chimneys, bringing in leaves, twigs, and other flammable materials. They may also:
- Fall into the fireplace and enter the home
- Get stuck and die, creating sanitation issues
- Bring fleas, ticks, or mites indoors
Bats
Bats can squeeze through openings as small as 3/8 inch. They are known to roost inside chimneys, especially if the flue is dark and warm.
Bat guano (droppings) can:
- Carry histoplasmosis, a harmful respiratory disease
- Smell horrible
- Create long-term cleanup costs
The Dangers of Ignoring Spark Arrestor Weaknesses
If you suspect your spark arrestor is damaged or vulnerable, it’s critical to act quickly. Here’s what can happen if you delay:
Fire Hazard
Animal nests and debris can ignite when you use your fireplace or wood stove. Even if a full fire doesn’t break out, smoke can back up and fill your living space.
Carbon Monoxide Poisoning
A blocked flue can prevent exhaust gases from venting properly, leading to a silent buildup of carbon monoxide which is a deadly and odorless gas.
Expensive Repairs
Once animals are inside your chimney or flue, professional removal, chimney cleaning, and possibly structural repairs may be required. It’s far more cost-effective to prevent the issue in the first place.
Health Risks
Droppings, urine, dander, and parasites from wildlife can all pose health risks to your family, especially when they accumulate in a chimney used for heating.
How to Prevent Wildlife Intrusion Through Spark Arrestors
Luckily, this is a preventable problem with the right approach.
1. Install a Full Chimney Cap with Integrated Spark Arrestor
The best protection comes from a high-quality chimney cap that includes:
- A built-in spark arrestor mesh
- A solid rain cover
- Wildlife-proof construction (steel or copper)
- Secure mounting hardware
Look for mesh with ⅝-inch openings, which is small enough to stop embers and most animals while still allowing proper airflow.
2. Hire a Professional Installer
Chimney caps and spark arrestors need to be custom-fitted and securely attached. A loose or poorly aligned unit is an open invitation for wildlife. Professionals will ensure:
- Proper sizing for your flue
- Tight, animal-proof installation
- No airflow disruption
At Abra Kadabra Pest & Wildlife, we also inspect the chimney structure and flue for other potential entry points or damage during installation.
3. Add Wildlife-Resistant Mesh or Guards
If you already have a cap and spark arrestor but live in an area with aggressive wildlife, consider adding reinforced steel mesh or squirrel guards around the top of the chimney.
These guards are handy for deterring raccoons, who can pry open weaker materials or damage older installations.
4. Schedule Regular Chimney Inspections
Have your chimney and spark arrestor professionally inspected and cleaned at least once per year—ideally before fireplace season in the fall.
During an inspection, technicians can:
- Clear away nests or debris
- Check for rust, damage, or loosening
- Recommend upgrades if needed
5. Monitor for Signs of Intrusion
Between inspections, keep an eye (and ear) out for:
- Scratching or chirping sounds from the chimney
- Visible nesting material near the flue
- Strong odors in the home
- Smoke is not venting properly
In Conclusion
Your spark arrestor may be small, but the consequences of a damaged or poorly maintained one are anything but. Wildlife can and will exploit weaknesses at the top of your chimney, especially when the temperatures drop and they’re looking for warmth.
Preventing wildlife intrusion through your spark arrestor isn’t just about comfort, it’s about protecting your home from:
- Fire hazards
- Smoke damage
- Dead animals
- Pest infestations
- And expensive repairs
The good news? A well-installed, wildlife-proof chimney cap and spark arrestor system is your first and best defense.
Need help securing your chimney? Contact Abra Kadabra Pest & Wildlife today for professional spark arrestor inspections, chimney cap installations, and wildlife prevention services. Let’s keep your chimney warm, safe, and animal-free.
