The building will be closed to both staff and public until October 27 while a full deep clean is carried out across the building.
The immediate closure will disrupt upcoming weddings, registrars and archive appointments.
Council bosses will contact residents due to wed over the next four days to postpone plans.
The launch of the exhibition ‘I Grew Up in the 80s’ as part of Experience Barnsley’s phased reopening will also be halted until October 28.
A spokesperson for Barnsley Council said: “We’re sorry about the disruptions and upset that this may cause.
“We are trying to minimise this as much as we can, but the welfare and safety of our staff and the public will always be our first priority.
“We urge everyone to follow the government guidance to save lives and prevent our NHS from being overwhelmed.”