Bats get into barns and attics through small gaps, often at the eaves, soffits, rooflines, vents and chimneys, and the openings can be far smaller than people expect. Michigan's DNR guidance is prevention first: seal the building and keep attic and vent screens intact. Exclusion is timing-sensitive, so the work is planned around state rules rather than rushed.
Key takeaways
- Bats can fit through holes as small as half an inch, so a gap that looks too small for an animal still needs checking.
- The Michigan DNR's homeowner guidance is prevention first: seal the home and other buildings to impede entry.
- The places to check are the eaves, soffits, rooflines, vents and chimneys.
- Attic and vent screens should stay intact, because a torn or missing screen becomes a route into the roof space.
- Exclusion is timing-sensitive, so the work is planned for the specific building rather than done at the first sighting.
- Any wildlife work is handled by an operator who follows state rules, and no dates are given on this page.
How do bats get into a barn or attic?
Bats enter through small gaps, and the openings can be far smaller than most people expect. Michigan's DNR says bats can fit through holes as small as half an inch, so careful inspection comes first.
An old barn or farmhouse has more places for an animal to get in than a tight modern building would. Boards pull away from the frame, flashing lifts, and vents lose their screens over the years. Each one is a possible route into the roof space, where bats can shelter out of sight from the ground. The openings are often high on the building, which is why they are easy to miss from a driveway. Bats can use openings that people would not think of as entrances, which is one reason the inspection should be thorough.
The state's guidance treats prevention as the first tool. Sealing the building, and any other buildings nearby, impedes entry, and it works best when the openings have been found rather than guessed at. Looking for the entry point from outside, at the roofline and the top of the walls, is the usual place to start, and a second look from a different side often shows a gap the first one missed.
What does prevention-first mean in practice?
It means finding and closing the openings bats can use, and keeping the ones already closed closed. The DNR's homeowner guidance is built around that sequence.
The DNR's advice for homeowners is to seal the home and other buildings to impede entry. For a barn or an old farmhouse, that means working around the outside of the building in an orderly way, so that each gap is closed and none is left as a way back in. Working methodically matters more than working fast. Working on one side at a time and keeping track of what has been closed makes the inspection easier to finish.
Screens matter as much as boards. Attic and vent screens stop an opening from becoming a route, so a torn or missing screen should be replaced rather than left alone. The goal is a building with no easy way in, which is a different aim from simply removing the bats that are already there. Prevention is what keeps the next season from starting the same way. Replacing a screen is one of the simplest steps on the list, and it is often overlooked.
Where should I look for gaps?
Check the eaves, soffits, rooflines, vents and chimneys first. Those are the joints and openings where a small gap is most likely to sit.
Eaves and soffits sit where the roof meets the walls, so they are the first place to look. Rooflines come next, because a gap at the edge of the roof boards can lead straight into the roof space. Both are worth checking from several sides of the building, since the light and the angle change what shows. A gap at the top of a wall, where it meets the roof, deserves the same attention as a gap at the very edge.
Vents and chimneys are the other usual routes. Attic vents and their screens, and the gap where a chimney meets the roof, should be inspected closely. A flashlight and a patient look from ground level will reveal many of the openings, though some sit high enough that a closer look is needed before any sealing is planned. Each opening should be noted so the work can be planned rather than improvised.
Why does exclusion depend on timing?
Bat exclusion is timing-sensitive, so the work is planned rather than rushed after the first sighting. No dates are given on this page, because the timing is set building by building.
A bat sighting in a barn or attic often prompts a call right away, and the urge to seal the building at once is understandable. The state's guidance, though, treats the timing of exclusion as part of the work itself. Sealing at the wrong moment is not the same as sealing at the right one, and the timing has to be set for the specific structure. Asking how the timing was chosen is a reasonable way to judge whether the operator has thought about the specific building.
This guide gives no calendar. An operator should explain the timing for a particular building and should follow state rules for any wildlife work. Those rules are not summarized here, because a summary would be a paraphrase rather than the rules themselves. Asking the operator to explain the timing and the rules is a reasonable first question.
Can a homeowner remove bats from a barn?
This page does not cover trapping or moving bats. Whether a permit applies, and how trapped animals may be handled, are questions for the state rules and for the operator who follows them.
The state's guidance on bats is about prevention, and this page stays with that. Whether a homeowner needs a permit for exclusion, and how trapped animals may be handled, are questions the state rules answer and the operator follows. Nothing here should be read as a substitute for either. A homeowner who is unsure which rules apply should ask the operator directly and get the answer in writing.
The homeowner's part is the one the DNR emphasizes: noticing the entry points, keeping screens intact and sealing gaps when the timing allows. Wildlife in a building can use more than one opening, so the search for gaps should cover the whole structure rather than only the spot where an animal was seen.
Why do old barns and attics suit bats?
Old barns and farmhouse attics can offer quiet, sheltered roof space that is out of sight from the ground. Gaps in the roof and eaves are what make that space reachable.
Old barns in farm and woodland country can have open doorways, loose boards and roof spaces that are rarely entered. A space like that can go unnoticed for a long time, and its quiet is part of its appeal to any animal looking for shelter. Woodland edges nearby add to the picture, since they are where many animals move between cover and open ground. Old barns that stand near woods and open fields can have more ways in than a barn with a solid, well-kept roof.
Farmhouse attics can be similar when a gap at the eave or the chimney leads into the roof space. The building's age matters less than whether it has gaps. A tight building is less likely to be used, and a leaky one is more likely to be, which is why the prevention work is aimed at the openings rather than at the age of the structure.
What should I note before calling?
Note where you saw bats, when you saw them, and which part of the building they came from. Describe any gaps you have already noticed.
A clear description helps the operator plan. Note the building, the room or roof space, and the spot where the bats were seen. Record whether the animals were seen once or repeatedly, since a single sighting and a pattern of sightings call for different questions. Mention whether the bats were seen inside the building, in a room, or outside near the eaves, since the location tells the operator where to look.
Describe any gaps, torn screens or damaged vents you have already noticed, and say which side of the building faces the woodland or field edge. Photographs of the outside of the building are useful, especially of the eaves and the roofline. The more exact the description, the more easily the openings can be checked on the first visit.
When should I call about bats?
Call when bats are seen in an attic or barn, or when you notice gaps at the eaves, soffits, roofline, vents or chimney. Phones are answered 24/7, and a visit the same day only when a technician is free.
Early contact lets the work be planned properly, because exclusion depends on timing and on finding every entry point. A call when you first notice the signs is more useful than one made after the building has been open for a long period. Waiting does not make the entry points easier to find.
You can reach the line at (855) 974-4733. Tell the person who answers where the bats were seen and which entry points you have noticed. No arrival time is promised, and the operator will explain the timing for your building before any sealing is scheduled. Phones are answered 24/7, so a call can be made at any hour.
Frequently asked questions
Can bats really fit through a half-inch gap?
Michigan's DNR says bats can fit through holes as small as half an inch. That is why a gap that looks too small for an animal still needs checking. A gap at a soffit or a chimney cap is the kind of opening that is easy to overlook from the ground. A careful look from several sides of the building is the best way to find them.
Should I seal the building before the bats leave?
That question depends on timing, and the answer comes from the operator who follows state rules. Exclusion is timing-sensitive, so the order and timing of sealing are worked out for the specific building. This page gives no dates, because the timing is set building by building.
Does a bat sighting in summer mean the building is infested?
Not necessarily. A sighting is a reason to inspect the building for entry points and to plan the work, but it does not by itself show how many animals are present or where they roost. A technician can check the roof space and the outside of the building before deciding what comes next. Writing down how often the animals were seen is a useful record for the visit.
What is the first thing to check on an old barn?
Start at the eaves and soffits, then move to the roofline, the vents and the chimney. Look for gaps large enough to admit a small animal, and check that the attic and vent screens are intact. Note each opening so the work can be planned rather than improvised. Check from several sides of the building, not just one.
Where do I find the state's guidance on bats?
The Michigan Department of Natural Resources publishes homeowner guidance on nuisance wildlife, including bats. The guidance is prevention focused and covers sealing the building and checking the usual entry points. Read it alongside the advice of the operator, who follows state rules for any wildlife work.
Can a homeowner do the prevention work alone?
The prevention steps the state describes are the homeowner's to check: looking for gaps, keeping screens intact and noticing entry points. Closing gaps and handling any bats inside are more involved, and this page does not describe how to do either. Those are the parts to plan with the operator. Asking the operator which steps are yours and which are theirs is a sensible way to divide the work.
Sources
This guide is general information for Montcalm County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.