In a seismic assessment report received by the council last month, several council-owned buildings were classified as earthquake-prone under the new building standard (NBS) rating system.
The Balclutha Public Library scored a 5% strength rating, meaning it is extremely likely to be damaged in the event of an earthquake.
It was the worst-ranked of the council’s buildings.
Council service delivery group manager Jules Witt said the library’s low rating was caused by the old Carnegie brick section at the front of the library, built in 1913.
The remainder of building, which was constructed in the late 1980s as a makeover for the original building, was "perfectly safe" and not earthquake-prone.
"It’s only the bit at the front ... and that’s why it [the rating] is so low because if one part of the building is low then the whole structure is set to that same level."
It was a matter of weighing up the risks, and the Clutha District was at a very low risk of a damage-causing earthquake, Mr Witt said.
It would be several months before the council received information on the cost of the work required to strengthen the council’s earthquake-prone buildings.
As per legislation, the council had up to 35 years to upgrade or make a decision to not use the building.
Clutha Mayor Bryan Cadogan said the library was a high priority given its earthquake rating.
He was concerned about the cost of any upgrades but it was something the council had a responsibility to face, he said.
