Residential Bat Problems FAQ

Answers to the Most Common Questions Homeowners Ask About Bats in Houses

Benjamin Vaughan, residential bat specialist in Ontario, Canada — Benjamin Vaughan of Bat Control Specialists
A residential bat specialist serving Ontario, Canada.

Arrows pointing to common gaps on a house where bats may enter, including ridge vents, chimney tops, soffit gaps, siding gaps, roof intersections, and missing drip edge. — Most residential bat problems begin with small gaps around rooflines, soffits, chimneys, fascia, brickwork, vents, or attic spaces.

Bats in a home can be confusing, stressful, and frightening.

Most homeowners do not know whether they have one lost bat, bats living in the attic, bats in the walls, or a recurring structural problem that has never been properly fixed.

This FAQ answers the most common questions homeowners ask about residential bat problems, bat removal, bat exclusion, bat-proofing, bat droppings, bat entry points, and what to do when bats are getting into a house.

Part 1: Bats Getting Into the House

1. Why are bats getting into my house?

Bats usually get into houses because they have found small gaps in the structure that lead into attic spaces, wall cavities, soffits, chimneys, rooflines, or other hidden areas.

They are not chewing their way in. They are using construction gaps that already exist.

Common bat entry points include gaps where soffits meet brick, chimney and flashing gaps, roofline openings, fascia gaps, loose siding, missing or poorly installed drip edge, gaps around vents, roof intersections, dormers, and construction joints.

Bats can use very small openings, and many of those openings are difficult for homeowners to see from the ground.

2. How do bats get into the attic?

Bats usually enter the attic through small gaps along the roofline or upper structure. They may crawl through a narrow opening and then move into the attic, soffit, wall, or roof cavity.

Common attic entry points include gaps under shingles, missing drip edge, open fascia returns, chimney flashing gaps, roof and wall intersections, soffit gaps, gable vents, ridge vent problems, and loose siding near the roofline.

The visible hole is often only part of the problem. Homes usually have many potential bat entry points.

3. How small of a gap can bats get through?

Scale diagram showing a pencil measuring 1¼ inches long by ¼ inch high to demonstrate the small size of bat entry gaps. — A bat entry gap does not need to be large. This scale diagram shows a 1¼ inch by ¼ inch opening, demonstrating how small some bat entry points can be.

Bats can use surprisingly small gaps. A gap does not have to look large from the ground to be usable by bats.

Long, narrow construction gaps are especially common. A small opening along a soffit, fascia, chimney, or roof edge may be enough for bats to squeeze through.

This is why bat-proofing requires careful inspection and sealing of potential entry points, not just the obvious hole.

4. Do bats chew holes into houses?

No. Bats do not chew into houses like mice, rats, or squirrels.

Bats usually use openings that already exist. These may be construction gaps, roofline gaps, missing flashing details, loose siding, open soffit edges, chimney gaps, or areas where building materials were never properly sealed.

That is one reason bat control is different from general wildlife control. The problem is usually not one large hole. It is often many small structural openings.

5. What are the most common bat entry points on homes?

Common bat entry points include:

gaps between soffit and brick
chimney flashing gaps
missing drip edge
fascia gaps
gaps under shingles
roof intersection gaps
loose siding
gable vents
ridge vents
dormer corners
vents and wall penetrations
gaps around additions
open construction joints

Bats prefer protected gaps that allow them to crawl into warm, hidden spaces. Many of these openings are high on the structure and difficult to see without a proper inspection.

Common Bat Entry Points on Ontario Homes

Most bat problems begin with small construction gaps around the upper parts of the house. These entry points are often difficult to see from the ground, but bats can find and use them repeatedly.

Broken caulking and open gap between chimney bricks and flashing that can allow bats into a home — Broken caulking between the chimney brick and flashing has left an open gap that bats can use to enter the structure. Chimney flashing areas are common bat entry points when old sealant cracks, shrinks, or pulls away.

Large gap between aluminum fascia and brick wall on an Ontario home. Openings like this can allow bats to enter wall cavities, attics, and roof systems. — A large gap between the aluminum fascia and brick wall. Openings like this commonly allow bats to access concealed areas of a home.

Fascia Gap at Roof Peak Bat Entry Point — A gap in the fascia at the peak of the roof. Openings like this can allow bats to enter the roofline, soffit, attic, or wall spaces behind the exterior trim.

Large gap between the soffit and brick wall on an Ontario home. The rough-faced brick prevents the soffit trim from fitting tightly against the wall, creating a bat entry point. — The irregular surface of the brick prevents the soffit trim from sealing tightly against the wall, creating a gap large enough for bats to enter the home.

6. How do I know if I have bats in my attic?

Common signs of bats in the attic include bat droppings, scratching or clicking noises, staining near entry points, bats seen flying around the roofline at dusk, or bats repeatedly showing up inside the living space.

Little brown bat droppings mixed with attic insulation inside an Ontario home. — Bat guano on top of attic insulation

Little brown bats roosting inside an attic between wood framing boards. — Little brown bats roosting inside an attic between wood framing. Hidden attic spaces, roof peaks, wall cavities, and wood framing gaps are common roosting areas for little brown bat colonies.

You may also notice small black droppings on siding, brick, decks, windowsills, or the ground below an opening. In the attic, droppings may be found on insulation, framing, stored items, or below roosting areas.

Bat droppings scattered on a white window ledge and brick sill below an active bat entry and exit point. — These bat droppings are not random — they mark an active bat entry and exit point directly above the window.

Bat droppings piled outside a gable end vent covered with mesh on an Ontario home. — Bat droppings below a gable end vent are a strong sign that bats are entering the attic near the vent area.

Many bat colonies are small, transient, seasonal and very hard to spot. You may not see bats hanging openly in the attic because they often live in the walls, tuck into tight spaces behind framing, insulation, roof boards, soffits, and wall cavities.

7. Do bats live in walls or only in attics?

It’s species dependant. Little brown bats prefer to live in attics, while big brown bats prefer to live in walls, between floors and less open cavity’s beside chimneys and framing.

Many homeowners think bats only live in open attic spaces, but bats often prefer tight, protected gaps. They may spend much of their time behind boards, under insulation, inside soffits, or in wall cavities where they are difficult to see.

That is why a proper inspection must include the outside of the structure, not just the attic.

8. What do bats sound like in walls and ceilings?

Wall Noises Are Rarely Diagnostic

Bats may make scratching, squeaking, clicking, crawling, fluttering, or rustling sounds.

These noises may come from the attic, walls, ceiling, soffits, chimney areas, or roofline. Bats are often most active around dusk and dawn, but noise can also occur during the day if bats are moving inside a wall or roosting area.

However bats and mice can sound almost identical when they are moving around inside walls, ceilings, soffits, or attic spaces. Scratching, light tapping, crawling, and rustling noises can be very difficult to identify by sound alone. Unless you are hearing the more diagnostic bat chirping or squeaking sounds, it is often impossible for a homeowner to know whether the noise is coming from bats, mice, or another small animal. In most cases, mice are far more common than bats inside wall cavities, but the sounds can be easily mistaken for each other without a proper inspection.

9. Why are there bat droppings on my siding, deck, or windowsill?

Droppings may collect on brickwork, siding, windowsills, porches, decks, roof surfaces, or the ground below an entry point. This does not always mean the bats are entering exactly where the droppings are found, but it gives an important clue about where they are spending time. Bat droppings outside a house mean different things depending on exactly where they are found.

Bat droppings found on the ground outside an Ontario home below a possible bat roosting area. — Bat poop outside on a porch

Exterior gas fireplace vent with bat droppings visible on the vent cap, indicating repeated bat activity. — Bat droppings accumulating on an exterior gas fireplace vent.

Bat droppings on porches are different.

Illustration of a modern house with arrows pointing to common bat entry points at the roof peak and dormer soffit-shingle junction. — This image shows two common bat entry points on a house: the roof peak area and the junction where the dormer soffit meets the shingles.

Little brown bat night roosting on a front porch wall near the door with text explaining bats roost here but do not enter here. — Bats may night-roost on sheltered porch walls near doors and lights, but these spots are not primary entry points. The real bat entry point is usually elsewhere on the house.

Droppings under a porch roof, deck roof, or overhang are always from night-roosting, not from a primary bat entry point.

Bats that live in a house often rest outside under sheltered porches, decks, and overhangs between feeding flights at night instead of returning all the way back into the roofline, wall cavity, or attic every time.

This night-roosting behaviour is one of the main reasons homeowners notice bat problems in the first place.

Bat Droppings Elsewhere Mean Something Different.

Bat droppings found along the side of a house, below a roof peak, near a chimney, on a roof, or directly under a high roofline gap are different. Those droppings are more likely to be directly below or near a bat entry and exit point. Bats do not choose their main entry points beside doors, under busy porch roofs, under deck roofs, or in areas with regular human activity. Their primary entry points are higher, more hidden, quieter, and farther away from doors, windows, people, noise, and movement — usually around rooflines, soffits, fascia, chimneys, shingles, peaks, and other concealed structural gaps.

Bat droppings on a white windowsill showing where bats are night roosting on the outside of an Ontario home. — Bat droppings collected on this windowsill because bats were entering and exiting through an opening directly above the window.

Bat droppings scattered on a roof directly below a bat entry and exit point on a brick wall. — Bat droppings on this roof show where bats are entering and exiting directly above the shingles.

10. What should I do if I find a bat inside my house?

If a bat is flying inside the living space, stay calm. Cover the heat registers! You don’t wan’t a bat diving down into your ducts.

Close interior doors to keep it contained in one room if possible. Put a towel under the door. Open exterior doors or windows leading outside. Do not turn off indoor lights because you don’t want to lose sight of the bat and contrary to popular opinion it will not help of hinder a bats ability to get out.

Do not swing at the bat with a broom or tennis racket. Do not try to grab it with bare hands.I

If there is any chance the bat had contact with a person or pet, especially if it was found in a bedroom while someone was sleeping, contact your local public health unit or medical authority for advice

A bat inside the living area may be a one-time event, but repeated bats inside the home usually means there is a bat colony or entry point somewhere in the structure.

11. Why do bats keep showing up inside my house?

Bats inside the living space usually mean bats are living somewhere in the structure and occasionally finding their way into the home.

Bats usually show up inside a house because they are entering high up around the roofline, attic, soffits, vents, chimneys, or other exterior gaps, then moving down through the internal wall framing. Once inside the structure, bats can descend beside pipes, wires, ductwork, chimneys, and other openings until they reach unfinished areas such as furnace rooms or basements. This is the most common ways bats end up in living spaces. They are almost never entering at ground level or through open doors and windows. In some houses, blocking inside the walls prevents bats from travelling all the way down; in others, the framing leaves a route open.

Cutaway house diagram showing how bats move from the attic to the basement through wall cavities beside a chimney, plumbing stack, electrical wires, and HVAC ductwork. — This cutaway house diagram shows how bats can roost in the attic, then crawl or drop down hidden wall cavities beside a chimney, plumbing stack, electrical wires, and HVAC ductwork before emerging in the basement.

Bats inside the living space usually mean bats are living somewhere in the structure and occasionally finding their way into the home.

Bats usually show up inside a house because they are entering high up around the roofline, attic, soffits, vents, chimneys, or other exterior gaps, then moving down through the internal wall framing.

Once inside the structure, bats can descend beside pipes, wires, ductwork, chimneys, and other openings until they reach unfinished areas such as furnace rooms or basements.

This is the most common ways bats end up in living spaces. They are almost never entering at ground level or through open doors and windows. In some houses, blocking inside the walls prevents bats from travelling all the way down; in others, the framing leaves a route open.

Once a bat finds its way from the attic or wall system into the living space, it may leave a scent trail that other bats can follow. That is why the number of bats showing up inside can seem unpredictable. A homeowner might get several bats inside one summer and then none for years, depending on the species, the colony, the season, and whether other bats continue using the same internal route.

With big brown bats, the problem is often more random because they tend to form smaller, more transient colonies. Interior appearances usually peak in summer, but big brown bats are year-round residents in Ontario and can even show up inside during winter. Little brown bats are different. Because they form much larger colonies, once they start finding a route from the structure into the living space, the problem can become much more frequent and may continue getting worse until the building is properly bat-proofed.

12. Can bats get into bedrooms from the attic?

Yes. Bats usually enter homes high up around the roofline, attic, soffits, vents, chimneys, or other exterior gaps. From there, they can move down through wall spaces beside pipes, wires, ductwork, and chimneys until they reach unfinished areas such as furnace rooms or basements. Once they are inside the living space, they may crawl under doors and move from room to room.

A startled couple waking up in bed as a little brown bat flies around their bedroom at night. — A bat flying around a bedroom at night is not a random accident. It usually means bats are already using the house and have found a way from the walls, attic, or ceiling into the living space.

Cross-section diagram showing how a bat moves from an unfinished basement up the stairs, under interior doors, and into a second-floor bedroom. — Cross-section image showing how a bat can move through a house by coming up from an unfinished basement, crawling under interior doors, going up stairs, and entering a second-floor bedroom.

Ontario building code requires airspace under interior doors, and that gap makes it very easy for bats to move through a house. Once a bat is in the living space, it can crawl under bedroom doors, basement doors, bathroom doors, and hallway doors while searching for a way out.

If a bat shows up in a second-floor or third-floor bedroom in the middle of the night, it is not coming after you. It is usually lost. Most of the time, the bat has come down through the structure, cannot find its way back into the wall or attic, and is desperately looking for another way out. Bats do not have many days to find their way back outside before they die from dehydration. This can happen with both big brown bats and little brown bats.

13. Are bats in the house dangerous?

Statistically speaking no. Bats are not trying to attack people, but bats inside a home should be taken seriously.

The main concerns are possible rabies exposure from direct contact, bat droppings accumulating in attic or wall spaces, bats entering bedrooms or living areas, odour from urine or droppings, contaminated insulation in larger or long-term colonies, and dead bats trapped inside walls or ceilings.

Most bats are not rabid, but rabies is serious enough that any possible contact should be handled carefully.

Big brown bat found inside an Ontario home near the ceiling — A big brown bat found inside an Ontario home. When a bat appears in the living space, it usually came from somewhere inside the structure, not through an open door or window.

Bat resting inside a house on a wood ceiling beam, circled in red. — A bat found inside a home resting on a wood ceiling beam. Bats that appear indoors are usually coming from hidden wall, ceiling, attic, or roofline areas — not through an open door or window.

A bat inside the living space is never a random one-time event, but symptomatic of an ongoing bat issue

14. What is bat exclusion?

Bat exclusion is the humane process of allowing bats to leave a structure while preventing them from getting back inside.

This is usually done with a properly installed one-way bat excluder over the active entry and exit point.

The bats leave naturally at night to feed. When they return, they cannot get back through the same opening.

Exclusion must be combined with bat-proofing, or the bats may simply find another way back in.

15. What is a bat excluder?

A bat excluder is a one-way device installed over an active bat entry point. It allows bats to leave but prevents them from re-entering through the same opening.

A proper bat excluder must be installed over the correct entry point, sealed properly around the right edges, safe for the bats to exit, suited to the shape of the opening, removed after the exclusion is complete, and followed by permanent sealing or bat-proofing.

Custom bat excluder installed over a roof edge opening to let bats exit safely but prevent re-entry — A custom bat excluder installed over the roof edge opening bats were using. The excluder extends beyond the gutter and angles downward so bats can escape easily, but cannot get back inside.

Custom Aluminum Bat Excluder Installed on Wood Siding — A custom aluminum bat excluder installed on a difficult roofline opening. Unlike cheap plastic or mesh excluders, this smooth aluminum excluder is shaped to fit the actual entry point and allow bats to leave safely.

Custom bat excluder installed under a roof valley on a metal roof to allow bats to exit but prevent re-entry — Bat excluder installed under a roof valley on a metal roof. This one-way device allows bats to leave safely while preventing them from getting back into the structure.

Bat excluder installed at the base of a chimney where bats were entering through gaps in the chimney flashing. — A bat excluder has been installed at the base of the chimney over an active bat entry point. The surrounding flashing and chimney base were then secured to prevent bats from re-entering once they exited.

A properly installed bat excluder allows bats to leave safely while preventing them from getting back in.

Not all excluders are safe or effective. Cheap plastic tubes and mesh excluders can fail and kill bats when used incorrectly.

Cheap mesh bat excluder installed over a roofline gap, showing improper bat exclusion work. — A cheap mesh bat excluder installed over a roofline gap. Mesh tubes like this are often poorly designed, unsafe, and unreliable for proper bat exclusion.

Dead Bat Stuck in Cheap Mesh Excluder — This is what failed bat exclusion can look like. A bat became trapped inside a cheap mesh excluder with sharp edges and died. Proper bat excluders must allow bats to leave safely without trapping or injuring them.

Cheap plastic bat excluder poorly installed at a soffit and brick gap — This cheap plastic bat excluder is a poor substitute for a properly fitted professional excluder. Plastic excluders often do not fit awkward soffit, brick, trim, and roofline gaps properly.

Broken cheap plastic bat excluder installed on a roof showing why poor bat removal devices fail — Cheap plastic bat excluders can break, collapse, or fail before the bat problem is solved. A proper bat exclusion device must be durable, weather-resistant, and installed as part of complete bat-proofing.

16. Can I just seal the hole?

No. There is no such thing as “just seal the hole” when it comes to bats.

Any opening you think bats are using is not the only opening available to them. The average house has countless potential bat entry points around the roofline, soffits, fascia, vents, flashing, chimneys, siding, trim, and construction gaps. Even if you happen to seal one active hole, it has almost no chance of keeping bats out of the walls or attic. More likely, the bats will simply move a few feet over and continue using another gap you cannot see from the ground.

It is also very difficult for a homeowner to identify the true primary entry points, especially with small bat colonies. Just as important, it takes experience to recognize the secondary and future entry points bats may use after the obvious hole is closed. Without years of bat-specific inspection and bat-proofing experience, most people simply do not know where to look, what matters, or how to seal the structure properly.

Although it is almost impossible that sealing one hole will trap an entire colony inside the walls or attic, it is also just as unlikely that sealing one hole will keep any bats out. At best, it may temporarily change where the bats enter and exit. Proper bat control requires a complete inspection, full bat-proofing of the structure, and humane exclusion only on the final active exit points.

17. What is the difference between bat removal and bat-proofing?

Bat removal is the process of letting the bats leave safely. Bat-proofing is the work that actually keeps them from getting back in. Excluders are useless unless the rest of the building is bat-proofed first. If every secondary and potential entry point is not sealed before the excluders go on, the bats will simply bypass the excluders and start using another gap somewhere else on the house.

Also there is no such thing as temporary bat removal. Bats cannot be “removed” from a house in any meaningful way unless the building is properly bat-proofed. Trapping bats and taking them away is illegal in most places, and even if bats are released somewhere else, they will (if the trap and release process doesn’t kill them) return to the structure they already live in.

Complete bat control means identifying the active entry points, excluding the bats humanely, sealing or protecting potential entry points, using materials that last, and preventing re-entry.

18. Do bat houses get bats out of a house?

No. A bat house is not a reliable way to remove bats from a home.

Bat houses may provide alternate roosting habitat in some situations and for some species, but they do not make bats leave an attic or wall space. If bats are already using your home, they are there because the structure provides warmth, shelter, and protection.

The only way to solve a residential bat problem is proper exclusion and bat-proofing.

19. Do ultrasonic bat repellents work?

No. Ultrasonic sound devices are not a reliable solution for bats in homes.

Bats may tolerate noise, move deeper into the structure, or ignore the device entirely. These devices do not seal entry points, remove bats properly, or prevent re-entry.

If bats can still get into the house, the problem is not solved.

20. Do mothballs, sprays, lights, or smells get rid of bats?

No. Mothballs, sprays, lights, strong smells, and home remedies do not fix a bat problem in a house.

They may irritate people, create odours, or give homeowners false hope, but they do not properly remove bats or bat-proof the structure.

If you pour too many mothballs in the attic you may end up smelling it inside the house. It won’t be pleasant.

Man pouring mothballs into an attic with bats roosting above, showing a common ineffective DIY bat-control method.

Homeowner running out of a house overwhelmed by mothball fumes after trying to use mothballs for bat control.

Bats only leave when they are excluded correctly and prevented from getting back inside.

Man in an attic spraying bat repellent toward bats roosting on the peak rafters while some bats begin flying off. — Hasta la vista batty!

21. Can pest control spray for bats?

No. Never.

Bats should not be treated like insects or sprayed like pests.

Residential bat problems are structural problems. The bats are getting in because the house has openings they can use.

Sprays and poisons are illegal and repellents will not solve that.

The proper method is permanent bat-proofing with humane exclusion.

Bat Houses, Repellents, and Sound Devices Do Not Bat-Proof a House

Mothballs, sonic repeller, bat repellent spray, and bat house shown as common cheap cures homeowners try for bat problems. — These products do not remove bats from a house.

Bat house, mothballs, bat repellent, and sonic noisemaker thrown in a garbage can — Where they belong.

Bat houses, sprays, mothballs, and ultrasonic devices do not replace proper bat exclusion and bat-proofing.

22. When is the best time to remove bats?

The best time depends on the season, the species, and whether young bats are present. And definitely not winter.

Bat exclusion must be timed carefully so flightless young are not trapped inside. In colder months, hibernation and low activity can also make exclusion more complicated.

A proper bat specialist will consider the season, weather, bat behaviour, and legal restrictions before deciding how and when to exclude bats.

23. Can bats be removed in the winter?

No. In Ontario you cannot fix a bat problem in winter.

In Ontario houses, the two bat species homeowners are usually dealing with are big brown bats and little brown bats, and winter matters because they behave differently. Little brown bats go to caves to hibernate in winter. However…

Common Spots Where Bats Hibernate in Houses — Cross-section image showing two common winter hibernation spots for bats in houses: under attic insulation and inside the exterior wall of a finished basement.

Big brown bats typically stay in the houses year round and hibernate inside the walls, ceilings, attics, and hidden spaces of those homes.

That means big brown bats cannot be excluded in winter because they are not leaving the house at night to feed.

There are no insects, moths, or mosquitoes for them to eat, so they are not going outside the way they do in warm weather.

A bat may occasionally show up in a basement, attic, or living space during winter because it has briefly woken up to clean itself, defecate, urinate, or move, but that does not mean it is leaving the structure

Even if the bats are not active at the exterior, the house still cannot be properly bat-proofed in freezing Ontario weather..

A scared man sitting on a snow-covered roof with a caulking gun and ladder, showing how difficult bat-proofing a house in winter can be. — Trying to bat-proof a house in winter is dangerous, difficult, and often unrealistic. Snow, ice, freezing temperatures, and poor access make proper exterior sealing impossible.
It’s a good way to exit the gene pool early.

Comparison image showing caulking applied to a roof in warm weather versus winter conditions where exterior caulking will not cure properly. — Exterior caulking should only be applied when temperatures are consistently above zero. Applying caulk to roofs and building exteriors in winter conditions is only done by morons.

The caulks, sealants, roof silicones, flashings, and screens needed to permanently keep bats out require clean, dry surfaces and consistently above-freezing temperatures to cure and bond properly. Snow, ice, frozen materials, and covered rooflines also make it impossible to properly inspect and seal the real bat entry points. For those reasons, proper bat exclusion and permanent bat-proofing cannot be done in winter in Ontario.

24. Will bats leave on their own?

Will bats leave on their own?

No, not in any reliable or permanent way.

In Ontario houses, the two common species are little brown bats and big brown bats. Little brown bats go to caves for the winter, but they typically return each spring and may use several houses in the same area. Big brown bats live in houses year-round, form smaller colonies, go unnoticed for long periods, and are highly transient, moving back and forth among several local buildings. With either species, the number of bats in a house at any given time can be almost impossible to know because bats may come and go between different summer, maternity, male, and winter roosts. They may appear to leave for a while, but they do not willingly abandon a good house permanently. The only real solution is to physically bat-proof the building and humanely exclude any bats living inside.

25. What should I do if I find bat droppings?

Is bat guano dangerous?

Small amounts of bat droppings are not the danger people are often led to believe, especially with minor big brown bat activity in Ontario homes. The real concern people talk about is histoplasmosis, which is caused by a fungus called Histoplasma capsulatum. That becomes a serious concern only in extreme situations: large, long-term accumulations of bat guano, usually from major little brown bat colonies, where droppings have built up over years and stayed damp from large numbers of bats urinating on them. That type of cleanup can require HEPA-filtered equipment, protective suits, containment, vacuum systems, and sometimes opening parts of the roof or structure to remove the material properly. That is completely different from a few dry droppings in an attic, wall space, or on the outside of a house.

Small amounts of dry big brown bat droppings left undisturbed inside walls or attic spaces are not a threat to the people living in the home. They do not have some magical ability to travel through the house and make people sick. Outside, small amounts of droppings can usually be brushed away, washed away with a hose, or cleaned up without fear. Guano cleanup only becomes a real consideration in the most extreme cases, where a large number of bats have lived in the structure for a long period of time.

26. How can I tell bat droppings from mouse droppings?

Bat droppings often look like small dark pellets, but they usually crumble easily and may contain shiny insect fragments.

Mouse droppings are usually harder, smoother, and more solid.

Location also matters. Bat droppings are often found below roosting or entry areas, such as near chimneys, soffits, siding gaps, attic framing, or outside walls. Also you will have to look hard for mouse droppings. Bat droppings are far more obvious.

27. Do bats damage insulation?

Bats can contaminate insulation with droppings and urine, especially in long-term or larger colonies. But it’s unlikely to have any affect on R-value

Not every bat problem requires full attic restoration, only heavy contamination may require guano removal, insulation removal, sanitation, or replacement.

The need for cleanup depends on the colony size, how long the bats have been there, how much guano is present, and especially on whether the attic is being used for storage or has mechanical systems that need servicing.

Bat Guano and Contaminated Insulation

Large pile of bat droppings inside an attic from a long-term bat colony. — A large accumulation of bat droppings inside an attic. Heavy guano buildup like this usually means bats have been using the attic for a long time and the attic will need to be cleaned.

28. How much does bat removal cost?

The cost of bat removal depends on the size and complexity of the home, the number of entry points, roof height, accessibility, materials needed, whether cleanup is required, and whether the work includes proper bat-proofing. Typically it’s not inexpensive.

A cheap job that only installs an excluder over one obvious hole may not solve the problem.

The real cost is not just removing the bats. The real work is finding and fixing the structural openings so the bats cannot get back in.

29. Why do bat problems come back?

Bat problems come back when the structure has not been properly bat-proofed!

If an excluder is installed over one entry point but other gaps remain open, the bats will simply move to another opening. If poor materials are used, they may fail. If the inspection misses hidden entry points, the problem returns.

Bat problems usually return because the wrong company was hired, They do things like only focus on obvious entry points, install excluders without bat-proofing the home, use the wrong materials and generally lack the specialized tools equipment and experience needed to permanently solve the problem.

Proper bat control requires expert exclusion and prevention.

30. Why should I hire a bat specialist instead of a general wildlife company?

Split image comparing a frightened surgery patient with a family doctor and a wildlife control technician holding a skunk, raccoon, and squirrel to show why bat problems need a specialist. — Just sayin’

Bat control is specialized work.

Ladder set up against a brick Ontario home for inspecting bat entry points around the roofline, soffit, fascia, and eaves. — Proper bat control is a very specialized profession.

Many general wildlife companies are used to dealing with raccoons, squirrels, skunks, birds, mice, and other common wildlife problems. Bat work is different because bats can use extremely small gaps, travel through hidden construction spaces, and return if even one entry point is missed.

A bat specialist understands bat behaviour, seasonal timing, structural entry points, roof and construction details, proper exclusion methods, permanent bat-proofing, and materials that hold up over time.

A bat problem is usually not solved by sealing a few obvious gaps.

31. What should I ask a bat removal company before hiring them?

Ask these questions before hiring a company:

Do you specialize in bats?
Do you inspect the entire structure?
Do you use humane exclusion?
What kind of excluders do you use?
Do you seal all potential entry points or only the main hole?
What materials do you use?
Do you understand roof, soffit, fascia, brick, chimney, and flashing entry points?
How long is the warranty?
Does the warranty guarantee the bat problem is fixed, or only the workmanship?
What happens if bats get back in?

The answers will tell you whether the company is doing real bat-proofing or just temporary wildlife removal.

Wildlife control technician holding a service contract while a homeowner asks if the bat problem is actually guaranteed to be fixed. — A workmanship guarantee does not always mean the bat problem is fixed. Homeowners should ask whether the company guarantees the actual bat problem is solved, not just whether the work was performed.

32. Will my bat problem come back after the work is done?

No. If the home is properly bat-proofed, the bats should not be able to get back in. Expect the bats to try, test and probe the house for other potential entry points. This is why expertly done prevention work is necessary as the bats will try for years to get back into their old house.

Bat problems only return when the wrong company was hired, the wrong materials were used, the company only treated the obvious entry points and the home was never fully bat-proofed. Additionally exterior renovations or modifications to building exterior like a new roof, addition or chimney will absolutely create new openings a bats can use. New roofs are the number 1 cause of re-infestations for reputable bat specialist companies. In other words if you tear off the bat-proofing work expect the bats to return.

A proper company should guarantee that they will fix the bat problem and not just guarantee the “work” that they did.

Why Bat Problems Come Back After Incomplete Work

The top 4 things that allow the bats to come back. Other than you hired the wrong company (usually a non specialist wildlife company)

1. High up, difficult to reach spots neglected.

2. Hard to find spots, not found.

3. Hard to fix spots, ignored or fixed incorrectly.

4. Wrong methods or materials.

For hard to find spots you typically…

Bat droppings under a gas liner cap on top of a chimney. — Bat droppings under a gas liner chimney cap show bat activity in an area many wildlife companies fail to inspect. Gas liner caps are not bat-proof and must be modified safely, legally, and correctly.

…Need specialized knowledge to know how to modify safely

Quarter-inch mesh screen installed on B-vent chimney cap to keep bats out of the metal vent — Quarter-inch mesh has been screwed and caulked into place on the chimney cap to prevent bats from squeezing through the openings and travelling down the metal vent into the basement.

Wrong methods, wrong materials.

Roof vents covered with incorrectly sized one-inch mesh that will not keep bats out. — Incorrect bat-proofing work using one-inch mesh over roof vents. Bats can get through openings this large, so this type of wildlife control repair will not keep bats out.

For companies that mostly deal with raccoons, it can be hard not to treat every job the same.

Bat-proof box screen installed over a roof vent to keep bats out — A properly sized box screen can protect a roof vent from bats and other animals.

Hard to fix spots.

Foam backer rod installed in a large gap between the soffit and wall prior to caulking. This bat-proofing technique helps permanently seal openings used by bats. — Foam backer rods need to be installed in oversized gaps before caulking. Without a backer rod, caulking applied to gaps greater than about 1/4 inch can sag and fall out.

caulking up large gap between brick wall and soffits of a brantford ontario home - [ ] By Bat Control Specialists Canadas No1 bat control and bat removal company. — Wide bead being applied

“Bat-proofing” done with incorrect tools and materials

One-inch mesh installed over a soffit shingle intersection with a dangerous half-inch mesh bat excluder that bats can bypass. — Improper bat exclusion work using one-inch mesh at a soffit shingle intersection. Bats can pass through large mesh openings, and sharp half-inch mesh excluders can be dangerous and easily bypassed.

And done with the right tools and materials

Custom aluminum bat excluder installed with metal flashing at a roof, soffit, and brick wall intersection. — A custom aluminum bat excluder installed with metal flashing at a roof, soffit, and brick wall intersection. The flashing closes hidden bat entry gaps while the excluder lets bats leave safely.

Short cuts fail in bat-control.

Roof fascia and shingle intersection with failed spray foam repair where bats can enter through exposed gaps. — A previous wildlife control company attempted to seal this fascia-to-shingle gap with spray foam. The foam has broken down, leaving exposed openings that bats can easily use to enter the home.

Permanent solutions don’t

Potential bat entry gap sealed with caulking by Bat Control Specialists — After photo showing how gaps at soffit/shingle intersections should be sealed with high grade roof silicones. Foam as a backer can be used but must be coated with the right caulkings

Hard to reach peaks are a favourite entry point for bats.

The harder it is to reach the more attention it will probably need.

Custom aluminum bat excluder installed at the gable peak of a house for humane bat exclusion — A custom aluminum bat excluder installed high at the gable peak of a house. These roofline areas are difficult to access and require a properly fitted excluder so bats can leave safely.

Missed spots

Roof intersection with shingles lifted to reveal a hidden framing cap gap and exposed opening beneath the roofing materials. — Gap hidden beneath the shingles. Once lifted, the framing gaps where bats get in become obvious

Oopsie!

Hidden Bat Entry Point Under Shingles Missed by Wildlife Company — A hidden bat entry point under the shingles that was missed by a wildlife control company. Bats often use concealed roofline gaps like this to get into attics and wall spaces.

33. Are bats protected in Ontario?

Are bats protected in Ontario?

Yes. Ontario has eight bat species, and seven of them are currently listed as endangered. The only exception is the big brown bat. But regardless of a bat’s conservation status, killing bats is not an acceptable bat-control method.

Little brown bats were nearly wiped out in Ontario by 2013 but at of 2026 have recovered quite well.

Map showing little brown bat population decline in Ontario after white-nose syndrome and signs of recovery by 2025. — Little brown bat populations in Ontario were severely reduced by white-nose syndrome by 2013, but recent reports show signs of substantial recovery in Ontario 2025.

Chart showing the conservation status of Ontario’s eight bat species, with seven listed as endangered and the big brown bat not listed. — Chart showing the conservation status of Ontario’s eight bat species. Seven are listed as endangered in Ontario, while the big brown bat is not listed.

Proper bat control should always be done humanely, with careful attention to timing, maternity season, and safe exclusion methods that allow bats to leave without being harmed. Using poisons, traps, or lethal methods is not only unacceptable — it is completely illegal.

34. Can I remove bats myself?

No. Even general wildlife control companies across North America consistently fail at bat-control even tho they are supposed to be wildlife experts. A homeowner has no chance at doing this kind of work correctly without specialized tools, equipment and years of practical hands on experience.

Homeowner asking a laughing bat control specialist if he can fix a bat problem himself while the specialist holds a ladder and wears a tool belt. — A homeowner asks if he can fix a bat problem himself while a bat control specialist uncontrollably laughs his head off.

Homeowner in a blue shirt falling off a ladder near the roof while bats fly out of an attic vent. — Hmmmm.

35. What is the best way to permanently get rid of bats in a house?

The only way to permanently solve a residential bat problem is complete bat exclusion and bat-proofing.

Bat control specialist pointing at a billboard that says bat-proof the house and humanely exclude the bats. — The best way to permanently get rid of bats in a house is to bat-proof the structure first, then humanely exclude the bats from the final active entry points.

That means inspecting the entire structure, finding the active bat entry points, installing proper one-way excluders, allowing the bats to leave safely, sealing all potential re-entry points, using durable materials suited to the house, and confirming the home is properly bat-proofed.

There is no spray, sound device, bat house, mothball, or shortcut that replaces proper exclusion and prevention.

The excluder gets the bats out.

The bat-proofing keeps them out.

Need Help With a Bat Problem in Your Home?

If you are dealing with bats in the attic, bats in the walls, bats getting into the living space, bat droppings around the house, or a bat problem that keeps coming back, the solution is not guesswork.

Residential bat problems require proper inspection, humane exclusion, and complete bat-proofing.

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