Wolverhampton's Civic and Wulfrun Halls work halted over fears foundations would be crushed
A major overhaul of Wolverhampton's Civic and Wulfrun Halls was put on hold after engineers discovered refurbishment works would crush the venue's foundations.
Structural investigations carried out after restoration work had begun revealed the building would be damaged and designs had to be re-drawn.
It comes after Wolverhampton council confirmed the Civic halls will stay shut until 2020 and an extra £23 million is now needed to complete the project.
Councillors are expected to approve the additional cash at a full council meeting on Wednesday.
A report to the council read: "The most significant issue was that the exposure of the foundations during the enabling works, identified that the existing structure could not hold the weight of the refurbished building as originally proposed.
"Thus, the scheme needed to be redesigned to reduce the weight on the foundations."
The revamp - which will see extra seating across new balconies, improved and new bar and hospitality areas, ventilation, lifts and better access to the Wulfrun Hall - was originally due to cost £14.4 million.
Council bosses said the extra £23.6 million would come mainly from 'the sale of surplus council land and buildings', with a 'strong potential to secure external grants and funding from regional and national bodies'.
But it means major events booked at the Civic halls, including Jason Mansford and Sarah Millican, will not go ahead there as the venue will remain closed.
The report read: "The extended period of closure means that in the short-term, alternative venues will need to be found for key events.
"Unfortunately, a temporary reduction in staffing levels will be necessary given financial constraints, however key staff will need to be retained in order to maintain and build new relationships with promoters and partners."
It is also expected the improvement work will support an extra 236 'direct and indirect local jobs', the report read.
