The limited space in the eccentric but beloved Hulbert mansion in the Park Slope Historic District, home to the Poly Prep Lower School, significantly constrained the institution’s ability to teach its young students. A densely formed limestone and glass addition, designed with attention to sustainability, gives room to move and grow and simultaneously uplifts the mansion and the adjacent brownstones with the presence, strength, and elegance of its form and facades. The addition was awarded a LEED® Silver rating, making it the first school in New York City to be certified by the U.S. Green Building Council. Other commendations for Poly Prep Lower School include a 2008 Building Brooklyn Award and a 2009 New York Landmarks Conservancy Lucy G. Moses Award.