Donald Trump’s White House ballroom project received the approval of Washington’s planning authorities on Thursday, two days after a judge ruled work cannot proceed without Congress’s approval.

The National Capital Planning Commission, which ​is chaired by one of Trump’s former lawyers, gave the green light to the “East Wing Modernization Project” on Thursday, describing the ballroom as just the latest stage over two centuries of continuous changes.

“While some might wish for history in the world to stand still, the fact of the matter is that the White House complex has constantly evolved to meet the programmatic needs of the federal government and the office of the president,” said the commission chair, William Scharf. “I believe that in time, this ballroom will be considered every bit as much of a national treasure as the other key components of the White House.”⁠

The Republican president says the $400m, 90,000 sq ft (8,400 sq meter) ballroom ​will be a privately financed defining addition to the White House and ​a lasting symbol of his presidency.

The ballroom is part of Trump’s broader push to reshape Washington’s monumental core, which also includes plans for a 250ft (76 meter) arch and a ​multiyear renovation of the Kennedy Center performing arts complex. He has ​also ripped out and replaced the White House Rose Garden and added a wide ‌array ⁠of gilding to the Oval Office.

Phil Mendelson, chairman of the Council of the District of Columbia and a commission member, was critical of the process that began with the East Wing’s demolition and not with more careful deliberation.

“The fact that it was demolished atypically, before plans were presented, means that the iterative process was more fixed,” he said. “I don’t see any analysis of the square footage needs. I don’t see any analysis of why the structure can’t be lowered. We’re told for security reasons. Perhaps that’s correct. But there’s just no analysis … It’s just too large.”

The commission is one of two federal bodies, along with the US Commission of Fine Arts, assigned a role in overseeing key DC-area building projects.

Trump picked several members of both groups. Scharf, Trump’s ​ former ​personal lawyer, chairs the National Capital Planning Commission.

The justice department appealed against Tuesday’s ruling that the president cannot construct ​his planned ballroom on the site of the White ​House’s demolished ⁠East Wing without approval from Congress.

The federal judge in the case granted a request for a preliminary injunction by the National Trust for Historic ⁠Preservation, a ​non-profit organization that brought a lawsuit alleging Trump ​exceeded his authority when he razed the historic East Wing and launched construction on the ​new building.