The B5297 Oxford Street in Workington is closed.
High winds have caused a building roof to become unsafe.
Cumbria Police says that the road will been closed until further notice.
In a statement, Allerdale Borough Council said: "Allerdale's Building Control officers were called out overnight after part of the roof of a building in Oxford Street, Workington became loose.
"Both ends of Oxford Street and an area of Gray Street have been fenced off to ensure safety of members of the public and Oxford Street is closed to traffic in both directions.
"The building has been deemed a Dangerous Structure and contractors have been asked to carry out the work as soon as the wind has dropped and it is safe to do so."