In the latest renderings, the old Middlesex Courthouse in East Cambridge is barely recognizable.
Its hulking gray facade has been replaced with glass, and flecks of vegetation peek out from large windows on the upper floors. At its base, the building’s once impenetrable perimeter is fitted with 10 stores and restaurants, two dozen apartments, and a landscaped park.
That’s the new plan being advanced by Leggat McCall Properties , which wants to conduct a top-to-bottom renovation of the 22-story building after winning a bid to purchase it from the state last year. If its $200 million proposal is approved, construction could begin in early 2014.
“We think we’ve got a world-class vision to create a different kind of property than currently exists on the East Coast,” said Eric Sheffels, president of the Boston-based firm. He said the renovated building — with 18 floors of offices — will stand out for its unusual open air windows, landscaped open spaces, and collection of locally based retailers at street level.
“The retail is critical to creating the right atmosphere for the building and for the surrounding neighborhood,” said Sheffels. “We want to make it a place for local operators.”
Neighbors got their first look at the project Wednesday night. Many have been critical of Leggat’s original concept for offices, saying they favored proposals by losing bidders that included more residences.
Opened in 1974, the courthouse is a towering presence in a neighborhood of mostly low-rise commercial and residential buildings. It is laden with asbestos, and its interior became so dilapidated that court operations had to be moved to Woburn in 2008.
Instead of demolishing the courthouse, as some neighbors have proposed, Leggat wants to gut it, wrap it in glass, and build a new retail and residential base. The renovated building, designed by Elkus Manfredi Architects, would also include a new park along Spring Street and up to 140 parking spaces underground.
Under the current plan, 24 apartments would be added to the lower floors, but Leggat executives said they remain flexible on the number of units and how they are configured within the building.
The state Division of Capital Asset Management agreed in December to sell the building to Leggat over two other finalists.
The parties still must close on the sale, and the state must relocate hundreds of prisoners who are housed in the top floors of the building.
Leggat, which needs permits from state and city officials, said it wants to start renovating the building about a year from now, with the work to be finished by 2016.
The exact mix of retailers remains subject to Leggat’s lease negotiations. But the firm’s executives said they are exploring urban grocery options, bike repair, and a mix of restaurants by local operators.
Leggat intends to lease the top 18 floors of the buildings to technology companies, hoping that its retail scheme and features such as a landscaped roof deck will appeal to young employees of such firms.
“The space will not look or feel like a traditional office building,” said Sheffels. “It will have more of an industrial feel, with concrete floors and two-story gathering spaces.
“It will also allow unparalleled amounts of natural light from the outside of the building.”
The property is a short distance from the Lechmere MBTA Station and Kendall Square, which has become a hotbed of growth for pharmaceutical companies and tech giants such as Google Inc., Microsoft Corp., and Amazon.com Inc.
The area’s office vacancy rate has dropped to about 7 percent, according to the real estate firm Jones Lang LaSalle.
While several office buildings are under construction in Kendall Square, nearly all of them will contain labs and offices for pharmaceutical companies.
Leggat executives said that creates an opening to build more space for technology firms and other businesses that will want to have a presence in the area.
Location: 40 Thorndike St., East Cambridge
Project: Complete renovation of the 22-story building, adding glass exterior to the tower, and retail stores and apartments to the base.
Uses: 460,000 square feet of office space; 15,000 square feet of retail, 24 apartments, 120-140 parking spaces.
Cost: $200 million.
Schedule: Construction begins spring 2014, finished by 2016.Casey Ross can be reached at firstname.lastname@example.org.