You come home one evening and hear scratching coming from the fireplace. You check the damper, and it is closed. The sound keeps going. You open it carefully, and the scratching gets louder. Something is in the chimney, and it is not just passing through. It has been up there for a while, and it is not getting out on its own.
Yes, chimney caps do keep squirrels out, but only when the right cap is installed the right way. An open chimney is basically a vertical shaft with nothing blocking the top. To these animals, it looks exactly like a hollow tree. They are great climbers and always looking for warm, enclosed spaces. They find uncapped chimneys all the time across Hamilton. A properly installed cap with heavy metal mesh closes that shaft off completely while still letting smoke and gas escape safely.
At Skedaddle Humane Wildlife Control in Hamilton, we deal with chimney situations every season. In this blog, you will learn why chimney caps are one of the best tools for keeping these animals out, what makes a cap actually work, and why calling our team at the first sign of chimney activity is the smartest step you can take.
What Do Squirrels Absolutely Hate?
These animals dislike enclosed spaces they cannot escape, surfaces they cannot grip, and openings that are blocked shut. That last one matters most when it comes to chimneys. A properly installed chimney cap with tightly woven metal mesh removes the open entry point entirely, and that is the single most effective deterrent available.
Repellents, noise devices, and other short-term measures rarely stop these animals from checking out a chimney. They are persistent and motivated, especially in fall when they are looking for warm shelter and in spring when females are searching for nesting spots. A chimney with an open or damaged cap will keep getting explored no matter what else is tried. Removing the access point is the only reliable long-term solution.
Squirrels also dislike having their scent signals removed from a space they have used before. When our team cleans a chimney after removal, we get rid of the scent markers that would otherwise pull the same animals back to the same spot the following season. That scent removal – combined with a properly installed cap – is what actually breaks the cycle of repeat entry.
Blocks the Open Flue
An uncapped chimney flue is one of the most accessible entry points on any home. Here is why blocking it with a cap is so effective:
- A Chimney Without a Cap Is an Open Shaft Into Your Home: Most standard chimney flues are between six and twelve inches wide, more than large enough for squirrels to drop into from the top. They can climb down a brick or masonry flue with ease, using the rough surface to grip as they go. Once inside, they find a dark, enclosed, sheltered space that is exactly what they are looking for. A cap that covers the full opening removes that entry point completely.
- Squirrels Find Open Chimneys While Exploring Rooftops: Squirrels travel along rooflines all the time, checking every opening and edge they come across. An uncapped chimney is one of the most obvious openings they find during these rooftop trips. They do not need to seek it out, they spot it because they are already up there. A cap that blocks the opening means they move on instead of dropping in.
- Capping the Flue Also Keeps Out Other Wildlife: An open chimney does not just attract squirrels, it pulls in raccoons, birds, and bats too. A properly installed cap with the right mesh size blocks multiple species at once. Our team checks mesh sizing and cap fit during every chimney assessment to make sure the cap in place actually provides full protection.
Heavy-Duty Steel Mesh
The mesh on a chimney cap is what does the real work of keeping squirrels out. Not all mesh is the same, and the difference between a store-bought cap and a professional-grade installation is significant.
Standard caps from most hardware stores are often made from thin aluminum or light galvanized steel with openings that are bigger than they should be. These animals can push through lightweight mesh with their front paws, and they will chew through thin material fast if they want to get inside. A cap that looked fine when it was installed may have gaps or weak spots that are only visible up close from roof level, which is one reason a professional assessment matters.
Professional-grade caps use heavy stainless steel mesh with openings small enough to block entry while still letting air and smoke flow freely. The mesh is chosen specifically for wildlife exclusion, not just to keep rain out. That difference matters because a cap built mainly for weather may not hold up against a determined animal pushing and pulling at the edges. Our team installs caps that are rated for wildlife exclusion and built to last through multiple seasons.
The fit of the mesh around the cap frame is just as important as the material itself. A mesh panel that is not fully secured leaves gaps along the edges that these animals find and use. A professional installation means every edge is checked, every fastening point is tight, and the cap sits flat on the chimney crown without gaps that could be widened by chewing or pulling.
Gnaw-Proof Materials
Squirrels have front teeth that never stop growing, which means they chew constantly. Any cap material that can be chewed through will be, eventually. Here is what makes gnaw-proof materials so important:
- Squirrels Can Chew Through Plastic, Aluminum, and Weak Metal: Consumer-grade caps made from plastic, thin aluminum, or light sheet metal are no match for persistent chewing. Squirrels can work through those materials in a matter of days when they want to get inside. A cap that has been partially chewed through offers almost no protection, and the damage is often not visible from the ground, so homeowners do not know it has happened until something gets in.
- Stainless Steel and Copper Stand Up to Persistent Chewing: Heavy stainless steel and copper are the materials that actually hold up over the long term. Both resist chewing, rust, and weather damage. A cap made from these materials holds up through many seasons without developing the weak spots that cheaper materials develop over time. Our team recommends and installs caps built from these materials specifically because of how well they hold up against persistent wildlife pressure.
- A Gnaw-Proof Cap Is a Long-Term Solution, Not a Temporary Fix: Replacing a lightweight cap that gets chewed through every season is a cycle that does not fix the underlying problem. A properly installed gnaw-proof cap, correctly fitted to the chimney crown, is a one-time professional installation that provides lasting protection. The right cap pays for itself by eliminating repeated replacement costs and the risk of damage from wildlife getting inside.
Prevents Trapping
Not every squirrel that ends up in a chimney meant to go there. Some fall in while exploring the rooftop and cannot get back out. Here is why a cap prevents that dangerous situation:
- Squirrels Can Fall Into an Open Flue While Exploring: Rooftop exploration is common, and an open chimney flue is a hazard that squirrels sometimes fall into by accident. The smooth inside walls of many flues give them nothing to grip on the way back up, which means an animal that falls in gets trapped. A trapped animal in distress causes significant damage to the chimney interior as it scratches and claws trying to get out, and it creates a serious health and odour problem if it cannot escape.
- A Trapped Squirrel Will Try to Get Into the Living Space: When a squirrel cannot get back out the top, it looks for another exit, which is often through the damper and into your home. A squirrel that pushes through a damper into a living space is a panicked, dangerous, and very difficult situation to deal with. Children and pets are especially at risk during these incidents. A cap that prevents accidental entry into the flue removes this risk completely.
- A Cap Also Keeps Out Rain and Debris: Beyond wildlife exclusion, a chimney cap stops rain, leaves, and debris from getting into the flue. Water getting into an uncapped chimney speeds up deterioration of the mortar, flue liner, and surrounding masonry. Debris that piles up inside the flue creates a fire hazard when the fireplace is used. A cap addresses all of these risks at the same time.
Blocks Nesting Scents
A chimney that has been used as a den or nesting spot even briefly carries scent signals that keep pulling future squirrels back to the same location. A chimney cap helps break that cycle, but only when it is combined with proper decontamination after any active situation is cleared.
Squirrels leave scent markers wherever they spend time, and those markers stay in the chimney long after the animal has gone. Future squirrels, including the same one coming back the following season, pick up those signals and treat the chimney as a known, safe spot. They are pulled toward it because it has been used before, and they will keep testing the entry point until they find a way in. Simply putting a cap on a chimney that has been used without also cleaning out the scent markers inside does not fully remove the attraction.
Our team treats the chimney interior as part of every removal and prevention job. Professional enzyme treatments break down the organic compounds in scent markers so the signal is gone, not just covered up. That treatment, combined with a properly installed cap, is what actually stops the pattern of repeat entry. A cap alone without decontamination makes entry harder, but it does not remove the reason the chimney is being targeted in the first place.
Squirrel Issues in Hamilton
Hamilton has a large and active squirrel population, and the city’s mix of older neighbourhoods, mature trees, and brick chimneys creates ideal conditions for chimney entry situations across the mountain and lower city. Many older Hamilton homes have original brick chimneys with aging mortar, worn caps, or no cap at all and those chimneys get targeted regularly by these animals during fall and spring.
Fall is the most active season for chimney entry in Hamilton. As temperatures drop, these animals are actively looking for warm, enclosed spaces to den up for the colder months. An open or poorly capped chimney is one of the most accessible options on any older property. Our team responds to chimney calls regularly through October and November as animals exploring rooftops find and enter accessible flues before the cold sets in.
Spring brings a different kind of chimney problem. Females looking for nesting spots in April and May will investigate chimneys as potential nursery locations. A chimney that provided winter shelter is especially attractive to a female looking for a safe, enclosed, elevated space to raise her young. Hamilton properties that had chimney activity in fall are at higher risk of a nesting situation the following spring if the chimney was not properly capped and treated between seasons.
Preventing Costly Damage with Skedaddle
When you call our team at Skedaddle, we start with a full inspection of your chimney – the cap condition, the crown and mortar, and any signs of current or past wildlife activity inside the flue. We figure out whether these animals are currently present, whether young are involved, and what the full scope of the situation is before any work begins.
Where these animals are currently inside the chimney, we put in one-way doors at the active entry points. These let them exit on their own but stop them from getting back in. After the chimney is clear, we remove the temporary devices and install a professional-grade gnaw-proof cap that fits properly and is secured tightly to the chimney crown. Homeowners should never try to cap a chimney that may have active wildlife inside – sealing them in creates a much harder and more costly situation than leaving the chimney open until a professional can look at it.
Decontamination and long-term prevention finish the job. Our team treats the chimney interior to remove scent markers, fixes any damage to the flue or surrounding masonry caused by wildlife activity, and makes sure the full chimney system is safe before we are done. You do not need to go up on the roof, inspect the cap, or try to handle any part of this yourself. Call our team at Skedaddle Humane Wildlife Control in Hamilton the moment you hear sounds from your chimney or fireplace and let us handle every step safely and completely.
Frequently Asked Questions
How do I know if a squirrel is in my chimney?
The most common signs are scratching, scraping, or chattering sounds coming from inside the fireplace or chimney, especially when the damper is closed. You may also hear falling debris, see nesting material near the fireplace opening, or notice a strong musky smell coming from the fireplace. If you notice these signs, do not open the damper. Call our team right away.
Can I use my fireplace if a squirrel is in the chimney?
No. Using the fireplace with a squirrel in the chimney creates a serious risk of injury to the animal, a fire hazard from nesting material igniting, and the chance that the animal pushes through the damper into your living space. Do not light the fireplace until the chimney has been professionally inspected and cleared.
Will a squirrel in my chimney eventually leave on its own?
Maybe, but not reliably. A squirrel that fell in accidentally may not be able to climb back out. An animal that entered on purpose may have started nesting and will not leave until the young are old enough to move. Waiting to see what happens risks more damage. Our professional assessment is the only way to know what you are actually dealing with.
What kind of chimney cap is best for keeping squirrels out?
A professional-grade cap made from heavy stainless steel or copper with tightly woven mesh and a secure fit on the chimney crown. Consumer caps from hardware stores are often made from materials squirrels can chew through or push aside. Our team installs caps specifically rated for wildlife exclusion.
Do chimney caps affect fireplace performance?
A properly fitted cap with the right mesh size does not hurt fireplace performance. In fact, it can improve performance by keeping debris out of the flue and protecting the masonry from water damage. A cap that restricts airflow was likely not sized correctly for the flue, another reason professional installation matters.
Can squirrels damage the inside of a chimney?
Yes. Squirrels scratch and claw at mortar joints, flue liners, and metal damper parts as they try to move around. Nesting material creates a fire hazard. Droppings and urine speed up deterioration of the masonry and surrounding materials. The longer it goes unaddressed, the worse the damage gets.
An Open Chimney Is an Open Door, Let Skedaddle Cap It Properly
A chimney without a proper cap is one of the easiest ways for squirrels to get into your home. And once they are in, getting them out safely and keeping them out for good takes the right process, the right materials, and a professional team that knows what they are doing.
Waiting to see if they leave on their own is rarely the right call. Damage builds up fast. Nesting material creates a fire risk. Droppings contaminate the flue. And without a proper cap and decontamination afterward, the same chimney gets targeted the following season again.
The good news is that you do not have to figure any of this out on your own. Our team handles every step from start to finish.
At Skedaddle Humane Wildlife Control in Hamilton, our team inspects chimneys, removes active squirrels humanely, decontaminates the flue interior, and installs professional-grade caps that are built to last. You do not need to go up on the roof or handle any part of this yourself. Request an estimate today and let our team protect your chimney before the next animal finds its way in.
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