The café at the Graves Art Gallery in Sheffield is shut because of a leak - with no date set for reopening.
A Museums Sheffield spokeswoman said repairs were needed as water had leaked from pipework on the roof.
“Sheffield City Council, who own the building, are currently exploring the best option for repair and we’re just waiting to hear back from them,” she said.
“But as such, we’re not able to confirm a reopening date at the moment.”
Visitors are being directed to the café at the nearby Millennium Gallery.
The Central Library and Graves Gallery building is being looked at by the council’s Chinese development partner, Sichuan Guodong Group, as a potential site for a five-star hotel.
The council will discuss the idea of keeping the gallery in the existing building should the scheme go ahead.
Earlier this month The Star revealed that Sheffield Town Hall was being considered as a new venue for the library.