The final component of Chapin's master plan is the completion of an 13,400 square foot two-story addition to the newly renovated Upper School.  The building houses grades 5 through 8 and adds a new library-information center, additional classrooms, small group rooms and offices arranged around central commons spaces on both floors, each of which will accommodate a variety of student activities.

The library/information and technology center, inspired by the farmhouse and barn vernacular that infuses the campus, is an airy, high-volume space featuring exposed structure. The lower, grade-level floor of the building will provide a dedicated “home” for fifth graders, who are transitioning into the Upper School.  The project was completed during the summer of 2015, opening in time for the new academic year.  Site improvements supporting the completed work include creation of a new vehicular entry arrangement providing greatly improved queuing capacity, relocation of play areas, creation of a new rain garden and Lower School entry court, as well as implementation of various infrastructural upgrades and storm water management strategies.