KITCHENER — The purchase of a small property paves the way for a big redevelopment of 2.4 hectares of land fronting along King Street West that will cost hundreds of millions of dollars.

The Zehr Group announced Friday it completed the purchase of 641 King St. W. in Kitchener, and now owns all of the land between the railway tracks and Wellington Street South, and into the block as far as the Ontario Seed property.

“It really allowed us to close off the entire block,” said Zac Zehr, manager of development for the Zehr Group. “We can now move forward with the whole master plan vision we have for the site.”

During the next two months, the company will apply for zoning changes and an amendment to the city’s official plan.

The changes are needed to accommodate the high-density, mixed-use redevelopment of the site. Preliminary plans call for one million square feet of new buildings — three condominium towers, an apartment building and office and retail space.

“Right now we have a huge team of consultants who are working with us behind the scenes, and we are getting very close to being able to move it forward into the public realm,” Zehr said.

The demolition of the modern wings of the former Kaufman mansion will begin in the spring. The original mansion will be preserved, and incorporated into the redevelopment.

The first phase of the redevelopment could begin this time next year, and will include residential, retail and office space along King Street West.

“Our site is challenging in that it is quite large in comparison to a more traditional downtown site,” Zehr said. “The overall plan at this point is to build in phases.”

The company calls the project SIXO Midtown. It will be across the street from Google’s Canadian engineering headquarters, a short walk to the future transit hub at King and Victoria streets and a short walk to the University of Waterloo health sciences campus also at King and Victoria.

At 2.4 hectares, it will be among the biggest redevelopments to ever happen in the city centre.

The existing strip mall was built when there were no constraints on suburban development that covered farm land. SIXO will replace that strip mall with a walkable, transit-oriented, high-density development right on the light rail line.

“We want to create an urban village,” Zehr said. “We want SIXO to be a people friendly place, a thriving community within a community where people can live, work and play.”