Haunted Town Hall Bob the Builder : Season 20 Episode 3

When the new Town Hall alarm keeps going off, Dizzy and Lofty are respectively excited and horrified by Mr Bentley's suggestion that it could be a ghost setting it off. Bob and Wendy eventually find the real culprits - bats that Bob accidentally trapped inside the chimney when he was working on it. To make sure the bats don't get hurt by living in the chimney, the team decides to create a new home for the bats on the roof.