Work will soon begin to stabilize the old gun battery overlooking the mouth of Halifax Harbour at the York Redoubt National Historic Site.

While part of the site built above the rocky shoreline remains open to the public, Parks Canada installed a fence in 2009 to keep people out of unstable areas. Even so, graffiti marks much of out-of-bounds area, a sign people are still finding ways to explore where they aren't allowed.

A new refurbishment project will involve removing two command towers and gun roofs, as well as stabilizing the shore battery, said Jonathan Nash, a project manager with Parks Canada.

"We want to prevent any loss of heritage value to any of the remaining structures of this area as well as improving public safety by mitigating some risks," said Nash.

Though it has been fenced off for seven years, graffiti shows people have been making their way into the site. (CBC)

Hastily built to protect Halifax

The historical site's original fortification was built in 1793, at the outbreak of war between Britain and revolutionary France. When French warships were reported near the Atlantic coast, harbour batteries were hastily erected to secure Halifax from attack by sea.

The gun battery was built as a temporary defence when the Second World War broke out, Nash said. After the war there was no need to protect the entrance to the harbour and the structures slowly deteriorated over time.

"It was built quickly in response to an immediate threat and as such it was rushed into construction," he said. "It's so close to the ocean with the saltwater spray and the wind, which rapidly deteriorates steel items."

Part of the York Redoubt National Historic Site was built at the beginning of the Second World War to fortify the entrance to the Halifax Harbour. (Paul Palmeter/CBC)

Open for bids

He said a 2015 assessment found there were some hazardous materials that should be removed

"There is some asbestos on site which was used in a lot of buildings from this era," said Nash.

The work could start before Christmas and there is a completion date of March 2017. Companies interested in submitting formal bids for the job are being invited to visit the site Nov. 9.

The cost of the project isn't known yet. The government will have a better idea on price when the tender for the work closes Nov. 15.