A car park less than two decades old needs over £1m of repairs to bring it up to modern safety standards.
Constructed in 2004, St Andrews car park in Norwich city centre is set to get around £1.2m of repairs.
The aim of the work is to save lives and prevent suicide attempts.
The cost has ballooned well beyond Norwich City Council’s initial expectations for the work, which was set at £300,000 in September.
Mike Stonard, cabinet member for inclusive and sustainable growth, said: "There are six parking levels and unfortunately the current construction of the car park doesn’t meet modern safety standards.
“We have consulted with partners, including the emergency services and industry experts to identify the most appropriate method of design for improving the car park to meet these standards.”
This includes new edging measures to improve the safety of the car park for users with a four-meter-high anti-climb fence around the top deck.
Mr Stonard said the discrepancy between the expected cost and the final amount was partly due to the cost of scaffolding, which he described as “extremely expensive”, and the inflating cost of materials.
The city council's cabinet agreed to award the contract for the works to Bawburgh Installations Ltd, at a meeting on Wednesday evening.
A planning application by the authority said: "The loss of life through suicide is a tragedy for the affected families, and also has a significant emotional impact on the emergency services and council staff that attend these incidents.
"As well as the untold emotional impact of suicide, it is estimated that the financial impact of each event on public services is £1.7m.
"They also affect the lives of 20 to 70 individuals, including those in the emergency services who have to deal with them."
City council planning officers have already approved the application.
If you need help and support, call NHS 111 and select option 2 or the Samaritans on 116 123. Both services are available 24 hours, 7 days a week. You can also download the Stay Alive app on Apple & Android.
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