Construction is underway on the $420 million expansion of the Wisconsin Center, 400 W. Wisconsin Ave. But at least one person involved thinks calling the convention center project an “expansion” shortchanges its potential impact.

“Let’s not call this an expansion. This is a completion of a vision people had 25 to 30 years ago,” said Wisconsin Department of Administration Secretary Joel Brennan at a ceremonial groundbreaking ceremony Thursday morning.

“This project has been in the works since the original building opened in 1998,” said Wisconsin Center District Board (WCD) board chair Jim Kanter. “I feel very confident that the convention center expansion will turn Milwaukee into a sought-after convention center destination.”

The project will add 112,000 square feet of exhibition space to the convention center, creating a 300,000-square-foot hall. A new 2,000-person ballroom and 24 meeting rooms will also be added. Multiple outdoor decks, an indoor waterfall and revamped common spaces will wrap the convention hall.

The expanded facility will fill two city blocks, running from W. Wisconsin Ave. to W. Kilbourn Ave., and from N. 6th St. to N. Vel R. Phillips Ave.

The expansion will allow one event to be set up while another takes place, a structure that project boosters believe would greatly increase the utilization of the entire facility.

“This expansion really puts a capstone on what has happened in Westown,” said area Alderman Robert Bauman, a WCD board member. The expansion, which replaces a surface parking lot, will bridge the gap between Fiserv Forum and the existing convention center and new Bradley Symphony Center.

“This convention center and this area have been home for some time to untapped potential,” said Department of City Development Commissioner Lafayette Crump.

“This is the fuel for growth,” said Milwaukee Bucks President Peter Feigin. “This is so desperately needed and so well thought out.”

Milwaukee County Executive David Crowley called it a catalyst for more people to come to Milwaukee and see all that the city has to offer.

General contracting is being led by a partnership of Gilbane Building Company and CD Smith. Design is being led by a partnership of tvsdesign and Eppstein Uhen Architects. Pre-construction site work has been underway for months already.

The event featured a who’s who audience, including VISIT board chair Eve Hall and past chair Omar Shaikh, Milwaukee Downtown president Beth Weirick, GRAEF CEO John Kissinger, Marcus Corp. CEO Greg Marcus, former WCD board chair Frank Gimbel and a number of lawmakers from both parties.