Common pipistrelles are Britain's most abundant bat but face roost loss through building renovation, re-roofing and rendering works conducted without surveys.
Pipistrelle maternity colonies roosting in roof spaces are vulnerable to construction works that seal access points, apply pesticide timber treatments or remove roofing tiles during the breeding season. Heat exposure in sealed roofs can kill pups rapidly. The legal protection for bat roosts extends to roosts found empty, meaning renovation does not require active bats to be present. Enforcement of roost protection law varies significantly between local planning authorities.