Excluding bats from a building
A single bat inside your home?
Bat colony roosting on or in your house?
There is no need to panic if you find bats in a building. Bats are simply small animals that are trying to find a suitable home. Some bat colonies can remain safely in buildings without creating a risk for humans. Assess your situation. Are the bats causing a problem? If so, is it the bats themselves, or the side effects of the bats (such as noise, smell or guano) that are the issue? Leaving bats where they are is usually the best option for bat conservation but may not be an appropriate option for the homeowner.
To find out more about what to do with bats in buildings consult or download Got bats: a BC Guide for Managing Bats in Buildings, and in french, Des chauves-souris: Guide a la gestion des chauves-souris dans les batiments en Colombie-Britannique.
See our other guides below:
- For Homeowners: see 7 Steps to Excluding Bats from Buildings Homeowners
- For Pest Control Professionals: see “7 Steps to Excluding Bats from Buildings for Pest Control Management Professionals”. There is a 2 page overview (pdf), and a 16 page booklet (pdf)
- For Builders: see the two page A Bulletin for Builders and BC Guide for Managing Bats in Buildings
- For Roofers and Chimney Professionals: see the two page A Bulletin for Roofers and Chimney Professionals and BC Guide for Managing Bats in Buildings
- For Realtors: see the two page Got Bats in a house for sale? A bulletin for realtors and BC Guide for Managing Bats in Buildings
If the bats are using an outbuilding, such as a barn or storage shed, you may be able to avoid contact with them and co-exist. Some people have lived with bats in their attic for decades since they do not come into contact with them and there are no issues of noise or smell. In other cases, where bats persistently find ways into the human living spaces or guano cannot be regularly cleaned out, exclusion may be the best option. The primary issue (after not having contact with bats) is usually containment of droppings (guano). Containment can often be achieved at relatively low cost. It is also often the best option when exclusion from drafty outbuildings is virtually impossible.
Bats may roost in many parts of a building structure including under roofing, siding, fascia boards, flashing and rafters, in cracks of the chimney or walls, behind shutters or under a porch roof.
To decide if you need to get rid of the bats from your house, first identify the problems they are creating. Most peoples’ problems are often a by-product of bats (e.g. noise, smell) rather than the bats themselves. Some of these issues can be addressed by the following:
- Remove accumulated guano (collect all bat mummies for data)
- Install a plastic barrier on floor and caulk joints in floor to prevent odour movement to human living quarters
- Replace stained insulation
- Install a pre-sealed plywood floor along human access routes and under roost(s) to catch guano and facilitate annual removal
- Special modifications and maintenance will be required with hard-to-access roosts
If you would like to get the bats out of your house, here are some sensitive methods to try:
- Install bat-houses in ideal areas nearby before you evict your bats
- Wait until the fall or spring, after bats have hibernated or migrated, before disturbing the colony
- When the roost site is empty, seal up all of the cracks to the roost site. Bats can get into spaces as small as 0.5 cm so this may be a difficult task!
Find out more about Bat Exclusion from Bat Conservation International (BCI).