BARNSLEY’S innovative new Light Box library building will now not open until the spring of next year, it has been confirmed.

The council has been forced to abandon an autumn opening and costs have now shot up to £6.7m, an increase of more than half the money expected.

That is because ground conditions have been discovered which have forced architects to redesign the building’s concrete frame and its underpinnings.

The library, which is currently under construction on the site of the 1970s’ block which housed the Superdrug and Ray Allen menswear stores, in May Day Green, was designed to replace the existing Central Library in Shambles Street which was demolished to make way for the new sixth form college.

When plans were announced in 2014, the project was expected to cost £4m, providing a saving for the council from the deal to develop the site of the old building and to be open by early 2017.

Both of those targets slipped, with costs creeping up to £5.3m - a figure which was approved by the council’s ruling cabinet - and the opening date put back until the autumn of this year.

However, signage on hoardings around the building site has now been changed to warn the public to expect an opening date in the spring of next year, due to technical problems with the construction of the building.

They had not been foreseen before contractors moved on site, but the council insist it is important that the work is completed to the highest quality.

Coun Jenny Platts, spokeswoman for communities, said: “The main reason for the delay is due to unforeseen ground conditions which resulted in the sub-structure and concrete frame having to be redesigned.

“The design of the concrete frame with its circular columns is a crucial feature to the interior finish of the library building, and to achieve a quality finish care is being taken not to rush these elements as the frame remains exposed in the finished design.

“The original cost approved by cabinet was £5.3m and this has been revised to £6.7m to cover the build costs, plus an additional roof terrace with internal floor space for flexible use, and replacement of the refurbished retail unit.

“The project is now making good progress which is visible on site and scheduled to open in spring 2019.”

The Central Library is currently based in temporary premises on Wellington Street and will remain open until the new building is ready.

The Light Box is part of a widespread regeneration project for the town centre, which includes redeveloping the old Metropolitan Centre as the Glass Works retail and leisure complex.

Costs for that have also gone beyond original expectations with development costs eating into a £10m contingency fund, which has now been topped up by the council.