Last week, we reported that CenterPoint Energy signed an agreement with United Properties to purchase 505 Nicollet Mal, otherwise known as the Neiman Marcus building. Terms of the deal were not immediately available.

However, Bloomington-based United Properties said Wednesday that it will complete renovations to the 100,000-square-foot, four-story building by spring 2014, when the purchase will close. CenterPoint will then complete the interior renovations and move its 255 employees who work downtown during the first quarter of 2015.

Meanwhile, United Properties will install a "significant" amount of new windows to the fortress-like structure, as well as a new entry from Nicollet Mall, and the conversion of the below-street level to parking. The firm declined to release the renovation's pricetag.

"The renovations we will complete ensure that the property will be transformed into a unique place to work right on Nicollet Mall, taking full advantage of surrounding amenities including light rail, skyway connections, retail and food opportunities and great visibility," said Bill Katter, executive vice president, United Properties, in a statement.

Shea Architects is working with United Properties, and HGA Architects, has been hired by CenterPoint Energy.

United Properties bought the building earlier this year for $5.5 million.

Janet Moore covers commercial real estate for the Star Tribune.