WATCH: Tearing down the old Champlain Bridge will cost at least $400 million

The federal bridge authority has come out with a preliminary estimate on how much it will cost to demolish the old Champlain Bridge, once the new one is up and running.

At a technical briefing Wednesday, officials suggested it would cost at least $400 million to tear down the old bridge. The work would begin in 2019 — assuming the new bridge opens on schedule in late 2018.

Officials suggest it will be a delicate operation, which would see the bridge taken down, piece by piece, over a three to four year period.

They expect much of the steel and other material from the old bridge will be barged away and recycled for other projects in the Montreal area.

Meanwhile, the bridge authority expects to spend $124 million this coming year to maintain the current structure.

There will also be two major work blitzes coming next month — the weekend of May 20-21, the outbound lanes will be closed, while the following weekend, May 27-28, the inbound lanes will be shut down.

Work crews will be busy those two weekends replacing expansion joints on the deck of the bridge.