More than �20m of taxpayers' money will need to be spent to repair the headquarters of Norfolk County Council so it can remain in use, it has emerged.

And it has also been revealed that a study into the long term future of County Hall also investigated whether it made more sense to move the county council to a new base elsewhere - although such a move has been ruled out as too costly.

The �22m structural maintenance bill for County Hall for the next 25 years, which officers say is vital to remain operational in the future, has been calculated after a study into the state of the building in Martineau Lane, Norwich.

The report highlighted a desperate need for repairs to the concrete structural frame of the building, installation of wall and ceiling insulation, removal of asbestos, refurbishment of toilet blocks, improved lighting and fire alarms and conversion of floors to open plan working.

Since last year, the entrances of the offices, which opened in 1968, have been protected by canopies to shield the 1,200 or so staff and visitors from any threat of falling masonry.

The report shows County Hall is currently liable to flooding, blocked toilets and temperature extremes, while making the building more energy efficient will cut the council's carbon footprint.

It states that by making a strategic investment in County Hall it will be possible to bring the existing building up to an acceptable standard.

The possibility of a new build was examined by NPS Property Consultants Ltd (NPS) on behalf of the county council, but has been rejected on cost grounds.

But other council leased or owned offices in and around Norwich look set to be closed, with staff switching to County Hall in an attempt to save about �2m a year.

Offices likely to be affected include Sapphire House, Vantage House, Charles House. Lakeside 500, Carrow House. some in the Jarrold Stand at Carrow Road, Lawrence House, Graphic House, Barton Way, Hooper Lane. Whiting Road, Bank Plain and and Blithemeadow Court.

Cliff Jordan, cabinet member for efficiency, said: 'County Hall has now been in use for more than 40 years and anybody who visits it will know it is showing its age and in need of investment. In terms of energy efficiency, it falls well short of modern requirements.

'With reduced numbers of staff based in the building and changing budgets, it's only right and proper to have carefully considered whether we should invest in the fabric of the building - or consider a new build elsewhere.

'The cost of a new build would simply be too expensive - far more than the proposal on the table.'

The council is, following its Big Conversation, making �135m worth of savings over three years, but leaders insisted the money to fix County Hall would not impact on services.

Ian Mackie, deputy leader of the council and cabinet member for finance and performance, said the money would come from the authority's capital fund, with the council also borrowing some money.

He said: 'No services will be affected, nor savings required from other departments. In regards to the Big Conversation, we always said we would become a smaller organisation and this project will unlock those savings as we reduce our office space requirements in Norwich.'

The proposed programme will be discussed first by cabinet on Monday and by members of the corporate resources and scrutiny panel the following day.

A final decision will be taken by full council on Monday, July 23.

dan.grimmer@archant.co.uk