Marriott International Inc. is boosting the room count at its Residence Inn property across the street from Philadelphia's City Hall.

The Marriott Residence Inn Hotel Center City Philadelphia on East Penn Square will expand to 324 guest rooms from 290 by converting the hotel's larger units into studios, the property's general manager, Ed Farrington, said in an email Wednesday.

It was not yet known when the conversion project would begin, he said. It follows a 2013 guest-room increase that brought the count up from 269.