When Bat Removal Fails: A Brantford, Ontario Case Study

Here’s what we found.

The Homeowners’ Problem

A retired couple in Brantford, Ontario contacted us after continuing to experience bat activity inside their home despite having previously hired another company to solve the problem.

The homeowners had paid approximately $1,500 for bat removal services. Unfortunately, the bats continued to appear inside the house after the work was completed.

Rather than continuing down the same path, the homeowners decided to seek a second opinion.

What we discovered was not unusual.

Here is What They Did. (It Wasn’t Much)

The previous company had performed some sealing work around the home and installed bat exclusion devices. However, the work focused primarily on a handful of obvious openings between the soffits and brickwork.

At first glance, the repairs appeared reasonable.

Upon closer inspection, however, several problems became apparent.

The caulking bead was narrow, offered minimal overlap onto the surrounding materials, and showed early signs of shrinkage. Standard cheap hardware store silicone not intended for exterior was used to seal the gaps.

More importantly, the work addressed only a small portion of the potential entry points available to the bats.

As a result, the exclusion devices were being asked to solve a problem that had never truly been fixed.

Needless To Say The Bats Kept Showing up.

Why the Bats Returned

This is where many bat removal projects fail.

The goal is not simply to seal the openings currently being used by the bats.

The goal is to identify and secure every opening that could potentially be used once the bats are excluded.

Bats that have lived in a structure for months or years are highly motivated to regain access. Once their primary entry points are blocked, they begin searching for alternatives.

If those alternatives exist, they will eventually find them.

What We Found

During our inspection, we discovered that sections of the aluminum soffits and fascia had become loose over time.

Because they were secured primarily with nails, years of wind movement and seasonal expansion had created openings large enough for Big Brown Bats to exploit.

These openings would not necessarily be a bat’s first choice.

However, once a colony becomes familiar with a structure, even less desirable openings can

Why Were These Areas Missed?

The answer is fairly simple.

At the time the original work was performed, the bats appeared to be using openings between the soffits and brickwork.

Those openings became the focus of the project.

Unfortunately, the house contained many other potential access points that were never addressed.

As our inspection continued, we kept finding more.become viable access points.

The Fix

The first step was improving the existing sealing work.

Using a wide-bead applicator, we applied a substantially larger bead of caulk over the original repairs.

For these protected areas beneath the roof overhang, we used a high-quality clear exterior latex caulk. Although it appears white when first applied, it dries clear and performs exceptionally well in sheltered locations.

The wider bead provides significantly better coverage and helps reduce future shrinkage concerns.

Securing the Structure

After identifying the vulnerable areas, we straightened the loose soffits and mechanically secured the fascia using aluminum zip screws fastened directly into the underlying framing.

We then secured overlap areas and other locations where determined bats might attempt to squeeze back into the structure.

This work eliminated the majority of the openings available to the bats.

The Roof Vent Problem

The home also contained several slant-back roof vents.

According to the homeowners, they had asked whether these vents required protection from wildlife.

They were reportedly told that because the vents were made of aluminum, bats could not use them.

We strongly disagreed.

The vent itself may have been metal, but can easily be damaged by raccoons and squirrels.

More importantly, wildlife companies know this & routinely work on projects where raccoons and squirrels tear into roof vents. Once damaged, these vents become potential access points for bats and other animals. Therefore we were surprised that the did not recommend taking  any steps to reinforce the vents.

To prevent future problems, we installed bat-proof vent covers designed to keep out bats, squirrels, raccoons, and other wildlife while maintaining proper airflow.

Additional Roofline Repairs

While working on the structure, we also identified several gaps at roof intersections and valley tops that could potentially be used by bats.

These openings are often overlooked because they are difficult to inspect from the ground and may only become visible during a close roof inspection.

Using high-quality roofing sealants, we permanently secured these vulnerable areas.

Bat Exclusion

The homeowners advised us that exclusion devices had previously been installed but had since been removed.

Because it was impossible to know with certainty whether all bats had already exited the structure, we installed one of our custom bat excluders over the primary area of concern.

Custom Bat Excluder

[Photo]

Unlike many inexpensive mesh excluders, our rigid aluminum designs cannot collapse, deteriorate, or become damaged by rodents and weather exposure.

The excluder allowed any remaining bats to leave naturally while preventing them from regaining access to the structure.

Why the Original Work Failed

Why the Original Work Failed

This project highlights one of the most common misconceptions about bat control.

Many people assume bat removal is primarily about installing an exclusion device.

It isn’t.

Exclusion is only one part of the process.

The more difficult part is identifying and securing every potential re-entry point before the bats are permanently excluded.

In this case, the bats were highly familiar with the structure.

Once their preferred openings were sealed, they simply began using alternative routes that remained available.

The original work addressed some of the active entry points.

It did not adequately address the structure as a whole.

As a result, the bats returned.

It did not adequately address the structure as a whole.

As a result, the bats returned.

Why Bat Control Is Different

Bat control differs from most forms of wildlife control because bats can exploit extremely small openings.

A gap that appears insignificant to a homeowner may be large enough for a bat to use.

For this reason, successful bat exclusion requires far more than simply finding the hole currently being used.

The entire building must be evaluated from the perspective of a bat attempting to regain access.

This requires an understanding of:

• Bat behaviour
• Building construction
• Roofing systems
• Ventilation systems
• Soffit and fascia construction
• Flashing details
• Common wildlife entry points

The challenge is not just removing the bats.

The challenge is making sure they cannot come back.

The Results

After completing the bat-proofing work, securing the roof vents, reinforcing the soffits and fascia, sealing the remaining openings, and installing a proper exclusion device, the structure was finally protected against re-entry.

The homeowners were provided with our lifetime warranty.

More importantly, they were provided with confidence that the problem had finally been solved.

Lessons From This Case

This project highlights several important facts about residential bat control:

Long-term success depends on thoroughly bat-proofing the entire structure.
Bat exclusion is only half the job.

Prevention work is just as important as exclusion.

Bats will actively search for alternative entry points when excluded.

Roof vents, soffits, fascia, and roof intersections must all be evaluated.

Missing even one opening can allow bats to regain access.

Long-term success depends on thoroughly bat-proofing the entire structure.

“Most pest control companies handle dozens of different pests. We focus specifically on bat exclusion and the unique building science required to permanently prevent re-entry. This is why I believer non specialists companies should not be used for bat control.”

Benjamin Vaughan/Residential bat specialist

Final Thoughts

We do not share this case study to criticize a specific company.

We share it because situations like this are extremely common.

Many companies are capable of installing an exclusion device.

Far fewer have the specialized knowledge required to permanently bat-proof a structure.

Bat control is ultimately a building science problem.

It requires understanding how buildings are constructed, how bats interact with those structures, and how to eliminate every realistic opportunity for re-entry.

When done correctly, bat exclusion is permanent.

When done incompletely, the bats eventually return.

If you’re dealing with bats in your home, choose a company that can explain not only how the bats will be removed, but how the structure itself will be permanently protected.

Benjamin Vaughan

June 2026

Learn More

If you would like to better understand the differences between bat specialists and general wildlife control companies, watch the video below.