How to remove bats from your roof safely and legally
Bats in your roof are a protected species in most places, which means you cannot kill them or seal them in. The legal way to remove them is exclusion: you install one-way doors that let bats leave but prevent them from returning, then seal entry points after they are gone. This takes two to four weeks during the active season (spring through fall) and costs between $300 and $1,500 depending on how many entry points exist and whether you hire a professional.
The timing matters. Bats raise young from May through August in most of North America. If you seal entry points while mothers are inside, the young will die and you may face fines. The safest window is September through April, when bats are hibernating or have left for winter. If you discover bats during breeding season, you must wait until late August or September to exclude them.
You have two routes: hire a licensed wildlife removal company, or do the work yourself if you are comfortable on a roof and understand the legal restrictions in your area. Either way, the process is the same: find all entry points, install exclusion devices, wait for bats to leave, then seal the holes permanently.
Key Takeaways
- Bats are protected by law in most states and provinces; killing them or trapping them inside is illegal and can result in fines.
- Exclusion (one-way doors) is the only legal removal method; it works during fall and winter when bats are not raising young.
- Entry points are usually gaps smaller than half an inch around soffits, fascia, vents, and chimney flashing where the roof meets walls.
- After bats leave, you must seal all entry points with caulk, hardware cloth, or metal flashing to prevent re-entry.
- Professional removal costs $300 to $1,500; DIY exclusion is cheaper but requires roof access and attention to detail.
Finding where bats are entering your roof
Bats need only a gap of 3/8 inch (about the width of a dime) to squeeze through. Look for their entry points at dusk by standing outside and watching where they emerge. They usually leave between 20 minutes after sunset and one hour after sunset. Mark the spots with chalk or tape so you can find them in daylight.
Common entry points are gaps where the roof meets the wall (soffit and fascia boards), around pipes and vents that penetrate the roof, gaps in chimney flashing, and spaces under loose shingles or siding. Use a flashlight and binoculars to inspect these areas closely. You may also see dark stains or droppings (guano) below entry points, which are a clue.
If you cannot find the entry points by watching at dusk, hire a professional for an inspection. They have thermal imaging cameras that show where warm air (and bats) are escaping. This costs $100 to $300 but saves time and prevents you from missing holes.
Installing one-way exclusion doors
A one-way door (also called a bat valve or exclusion device) is a tube or flap that lets bats push out but closes behind them so they cannot re-enter. You install it directly over the entry hole. The bat leaves normally, the door closes, and the bat is locked out.
You can buy exclusion doors online or from wildlife supply companies for $15 to $50 each. Common types are tube-style (a plastic or mesh tube with a one-way flap) or cone-style (a cone that funnels bats out but has no return path). Installation is straightforward: caulk around the edges to seal gaps, then attach the door with screws or adhesive according to the manufacturer's instructions.
Leave the exclusion doors in place for 7 to 14 days. This gives all bats time to leave. Watch at dusk to confirm no bats are entering. Once you see no activity for three consecutive nights, the bats have left and you can remove the doors and seal the holes permanently.
Sealing entry points permanently
After the exclusion period, remove the one-way doors and seal every hole. Use materials that bats cannot chew through: caulk (for gaps under 1/4 inch), hardware cloth or steel mesh (for larger holes), or metal flashing (for gaps around pipes or vents).
For small gaps, explore silicone caulk with a caulk gun, smooth it with a wet finger, and let it cure per the manufacturer's instructions (usually 24 hours). For larger holes, cut a patch of 1/4-inch hardware cloth slightly larger than the hole, find it with screws or staples, then caulk around the edges. For gaps around pipes or vents, install metal flashing or use expanding foam followed by caulk.
Inspect your work in daylight. Bats are persistent; even a small gap you missed will be found and used again. If you are unsure about sealing a particular spot, photograph it and send it to a wildlife removal company for feedback before you finish.
When to hire a professional instead of doing it yourself
Hire a professional if your roof is steep or high, if you are uncomfortable working at heights, if you find more than three entry points, or if you are unsure whether the bats are actually bats (some homeowners confuse them with birds or insects). A licensed wildlife removal company will handle the inspection, exclusion, and sealing, and will usually may provide the work for one to two years.
Ask the company whether they are licensed by your state or province and whether they carry liability insurance. Get a written estimate that lists the number of entry points they found, the exclusion method they will use, the timeline, and what happens if bats return during the may provide period. Some companies offer a payment plan if the cost is high.
Verify that they will not use poison, traps, or lethal methods. If they suggest killing the bats, find a different company. Many states have a list of licensed wildlife removal companies on their fish and wildlife website.
Preventing bats from returning after removal
Once bats are out and holes are sealed, maintain your roof to prevent new entry points. Inspect fascia, soffits, and flashing twice a year (spring and fall) for gaps, cracks, or loose boards. Replace damaged shingles promptly. Trim tree branches that hang over the roof, as bats use them as landing platforms.
Install bat houses on a pole or tree 12 to 20 feet away from your home if you want to support local bat populations without housing them in your roof. A bat house gives them an alternative roosting spot and may reduce the likelihood they will try to re-enter your home.
If bats return after exclusion and sealing, do not assume the first removal failed. Bats may have found a new entry point you did not seal, or a different group of bats may have moved in. Repeat the inspection and exclusion process, paying extra attention to areas you sealed the first time.
Legal and health considerations
Most bat species are protected under the Endangered Species Act or state wildlife laws. Killing, trapping, or poisoning bats is illegal and can result in fines of $500 to $10,000 or more. Some states require a permit even for exclusion work. Check your state fish and wildlife website or call your local wildlife agency before you start to confirm what is legal in your area.
Bat guano (droppings) can carry histoplasmosis, a fungal infection that affects the lungs. If you find a large accumulation of guano in your attic, wear a respirator mask and gloves when cleaning it up. Do not sweep or vacuum guano; spray it lightly with water first to avoid stirring up spores. If you have respiratory problems, hire a professional to clean the area.
Bats themselves do not bite unless handled. If you find a bat in your home, do not touch it. Open a window or door and let it fly out, or gently guide it into a box and release it outside at dusk.
Frequently Asked Questions
Can I use poison or traps to get rid of bats?
No. Poison and lethal traps are illegal in most places and cruel. Exclusion is the only legal method. If a company suggests poison or traps, report them to your state wildlife agency and find a different company.
How long does it take to remove bats from a roof?
The exclusion process takes 7 to 14 days once doors are installed. Finding entry points, installing doors, and sealing holes adds another 1 to 3 weeks. Total time is usually 2 to 4 weeks. Professional companies may work faster if they have crews available.
What if I find bats in my roof during spring or summer?
Wait until late August or September to exclude them. Sealing entry points while young bats are inside will trap and kill them. If you cannot wait, hire a professional who can monitor the situation and time the exclusion correctly.
Will bats come back after I seal the holes?
If you seal all entry points completely, bats cannot re-enter that space. However, they may find a new gap you missed or a different part of the roof. Inspect your roof twice a year and seal any new gaps when ready. Bats have excellent memory and will return to the same spot if they can.
Is it safe to do exclusion work myself if I am not comfortable on a roof?
No. Working on a steep or high roof is dangerous. Hire a professional if you are uncomfortable at heights. The cost of removal is less than the cost of a fall or injury.