How to get bats out of your attic
Bats in an attic are almost always a maternity colony — and in most states they are legally protected, so killing them is illegal. The only working method is a one-way exclusion device installed after pup-rearing season ends, followed by sealing every gap. This is one job where calling a wildlife professional is usually the right call.
Tools
- ✓
- ✓Histoplasmosis (a fungal disease) lives in bat guano. Always wear a respirator in an active attic.
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Materials
- +Mesh tubes or polypropylene netting installed over the exit hole so bats fly out but can't get back in.
- +For sealing every remaining gap larger than 3/8 inch — bats squeeze through surprisingly small openings.
- +After bats are out, neutralize the odor and dissolve droppings so you can vacuum safely.
Steps
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1
Confirm it's bats, not birds or rodents
Bat signs: brown smudge marks (body oil) on entry holes, droppings that crumble between fingers (mouse droppings don't), and squeaks at dawn/dusk when they leave and return.
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2
Check your state's pup-rearing window
You cannot exclude bats during pup season (typically June 1 – August 15 in most US states) — flightless pups will starve in the attic and adults will tear the house apart trying to reach them. Wait until after season, or treat in early spring before females arrive.
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3
Find every entry point at dusk
Sit outside on a calm evening 20 minutes before sunset and watch where bats emerge. Most houses have one main exit and 1–3 backup gaps. Mark them all with chalk or tape.
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4
Install a one-way exclusion device
Mount a Bat Conservation International approved netting tube or excluder over the main exit. Bats fly out and can't crawl back. Leave it up for 5–7 nights.
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5
Seal every other gap before removing the device
While the excluder is doing its work, seal every other gap >3/8 inch with copper mesh + caulk or expanding foam. After night 7, remove the excluder and seal that opening too.
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6
Clean the guano safely (respirator on)
Wet down droppings with the enzyme cleaner first to prevent dust from going airborne — histoplasmosis spores are the real hazard. Bag, double-seal, and dispose. Replace contaminated insulation.
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7
When to absolutely call a pro
Large colonies (50+ bats), heavy guano accumulation, attics with blown insulation, or any uncertainty about pup season. A wildlife removal pro experienced with bats is worth the cost — fines for illegal bat removal in some states exceed $1000 per animal.