Portland’s Planning Board unanimously approved the third and final phase of Maine Medical Center’s $525 million expansion project following a public hearing Monday night.

The approval will allow the hospital to build a 265,000-square-foot, six-story medical building offering 64 private patient rooms and cardiovascular care procedure rooms at the current location of Maine Med’s Gilman Street staff parking garage, hospital spokesman Matt Wickenheiser said in a news release.

Monday night’s Planning Board vote was 6-0, city spokeswoman Jessica Grondin said.

“This is a very important milestone for Maine Medical Center and for the community and we’re extremely pleased to be moving forward,” Jeff Sanders, executive vice president and chief operating officer for Maine Medical Center, said in a statement.

Before work on the third phase can begin, construction of a new staff garage at 222 St. John Street must be completed. The planning board approved that project on Sept. 11, and site work began on Sept. 17. Once that garage is operational, which is expected in 2020, work on the third phase can begin with removal of the Gilman Street garage.

Work on the new medical building will begin after the site is cleared, expected to take about six months, and the building is scheduled to be completed in 2022.