Capstone Partners, a commercial real estate development firm, has purchased the Group Health’s former Redmond campus.

The 28 acres sit between Microsoft’s main campus and the Overlake shopping neighborhood. The site will be used to build 1.1 million square feet of office and retail space, more than 1,400 residential units and nearly 300 hotel rooms, Capstone said in a release. The total square footage will be more than 3 million.

Capstone, and its investment partner Lionstone U.S. Land Two, purchased the land from Group Health for $32.55 million.

Site demolition and road and utility construction will start in the next few weeks, according to Capstone, with building construction expected to start in late 2013 or early 2014.

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The City of Redmond had adopted a Master Plan and Development Agreement for the site in 2011.

Mayor John Marchione said: “This change to Overlake embodies the community’s vision for the neighborhood, as well as the city’s overall vision to direct future growth into its two urban centers.”