Wild Bat Roost Welfare and Building Work

Bats roosting in buildings are legally protected, but construction and renovation work frequently disturbs roosts — causing welfare harm and criminal liability.

Key Facts

All UK bat species and their roosts are protected under the Wildlife and Countryside Act 1981 and Conservation of Habitats Regulations.
Bat roosts are protected whether or not bats are present — destroying a roost even in winter when bats are absent is a criminal offence.
An estimated 100,000 bat roosts in buildings are potentially affected by renovation and construction works annually in the UK.
Planning applications for works affecting potentially occupied buildings require a bat survey and mitigation licence.
Appropriate mitigation includes working outside the maternity season (May-August), installing replacement roost features, and ecological supervision.

Welfare Considerations

Bat roost disturbance during maternity season causes acute welfare harm — young bats unable to fly are separated from mothers or killed directly by building work. Maternity colonies are the most welfare-sensitive roosting assemblages: each lost pup represents both an individual welfare harm and a potentially significant population loss for species with low reproductive rates. The legal framework protecting roosts exists precisely to prevent these welfare and conservation harms. Compliance requires survey, planning, and often mitigation works, but the welfare protection achieved is substantial.

What You Can Do

Commission a bat survey from a licensed bat surveyor before any renovation work on older buildings.
Report suspected illegal disturbance of bat roosts to Natural England and local police wildlife crime officers.
Maintain existing bat access gaps in roof spaces and walls to retain roost sites during renovation where possible.
Install bat boxes on replacement structures when original roost features are unavoidably lost during building work.