Up to £283,000 could be spent to stop the roof at Norwich City Council's historic City Hall from leaking.

Council bosses say 'major repairs' are needed to the waterproof layer on the roof of the Grade II* listed building.

Councillors will next week be asked to agree that a contract for the work can be advertised.

Officers said, in a report which will come before members of the Labour-controlled council's cabinet: 'It has been patch repaired over the years, but a more permanent solution is now required.

'Water is leaking through the asphalt into the concrete roof structure where it is tracking along the heating pipes in the ceiling, causing them to corrode and leak water from the heating system.'

The council wants to install a modern roofing system and increased insulation over the main roof of City Hall and the council chamber.

Officers say that will make the roof weather tight and will be guaranteed for the next 20 years. They say it will also help cut heat loss.

And applying a new membrane will mean the council no longer has to re-apply solar reflective paint every two to five years.

Officers warned: 'If work is not carried out there will continue to be revenue costs due to continued patching, re-coating of solar paint and repairs to office space as and when the heating coils fail.

'The roof will continue to deteriorate at an accelerated rate causing increased disruption to employees on the third floor, and therefore disruption to services.'

A pot of £283,000 is available for the work, although council officers anticipate it will not cost the full amount. But they need to keep a contingency available in case unexpected issues crop up during the work.

The latest need for repairs comes as scaffolding still surrounds the clock tower on City Hall. Work on the landmark started in April with a budget of £200,000.

Four long vertical pieces of metal which sit on each corner at clock level, known as finials, need to be fixed, along with a fifth, right at the top of the tower.

Norwich City Council had planned to use a crane to remove the finials to be repaired.

But, after careful assessment, it was decided that could cause damage to the fabric of clock tower, so the work is being done in-situ instead.

Because the scaffolding accounts for at least half the cost of the work, the city council is also doing other repair work, including repointing some of the brickwork.