Cobb County-based WellStar Health System has acquired the former Marietta home of a pharmaceutical maker to expand its administrative offices.

WellStar acquired a nearly 20-acre parcel and three-story office building for $4.45 million along Sawyer Road. WellStar expects to move about 300 employees into the facility later this year.

WellStar spokesman Keith Bowermaster said the nonprofit health group will commit up to $5 million in renovations to the new site, and will also upgrade its current administrative offices on Sandy Plains Road.

The office is part of a three-building campus for Solvay Pharmaceutical, which was acquired by Abbott Laboratories in 2010, and vacated shortly thereafter.

Stream Realty Partners and Brookwood Investment Group were the sellers. The two other buildings are now occupied by Osmotica Pharmaceutical.

“With this purchase, we were able to take advantage of the real estate recession to buy this building and its furnishings at one-fifth the cost of new construction,” Bowermaster said in an e-mail.

The purchase, which gives WellStar room for future expansion, also eliminates the need for planned lease extensions and renovations at other facilities that could save the hospital operator up to $4 million, he said.