British authorities have admitted what every homeowner knows in their heart of hearts: renovations always cost more than you expect.

Parliamentary authorities said Friday the cost of repairing London's Elizabeth Tower — part of the Houses of Parliament, and known as Big Ben — is now estimated at $81 million. Previously estimates said it would cost $38 million.

The mid-19th-century clock tower that soars 315 feet into the air in the heart of London's political and diplomatic quarter is one of the capital city's most-visited buildings. The repairs are needed to fix decaying stonework and outdated electrical and plumbing systems. The last extensive repairs took place more than 30 years ago.

Authorities said the increased costs were related to the complexity of the project and the scaffolding needed to enable workers to reach heights safely. The works have been controversial because Big Ben's bell will fall silent on all but a few special occasions during the repairs. The restoration project is expected to take about four years.