Derby Assembly Rooms will be closed for at least 8 weeks, after a fire on Friday on the roof of the multi-storey car park next door.
Derby City Council say the damage to the roof was extensive, and has made the structure of the building unsound. That means it will take time to assess the damage.
Performances at the venue will not be able to go ahead, as services that supply the venue were housed in the plant room on the roof of the car park, which was destroyed.
The plant room will have to be demolished and replaced before the venue can re-open for performances.
Full Street, which is the road next to the car park, is still closed.