The White House said it will add a 90,000-square-foot State Ballroom on the site of the East Wing, expanding the executive mansion’s capacity to host large events. Press Secretary Karoline Leavitt told reporters the project is expected to begin in September and will be architecturally consistent with the historic residence while remaining structurally separate from it. The ballroom is budgeted at roughly $200 million and will seat about 650 guests, more than triple the capacity of the East Room. President Donald J. Trump and other private donors have pledged to cover the full cost, according to the administration. Washington-based McCrery Architects has been selected as lead designer, with Clark Construction managing the build and AECOM providing engineering services. The Secret Service will oversee any necessary security modifications. The White House said the facility is planned to be completed well before the end of Trump’s current term.