Italian stonemasons working for Joseph Mandes Company of Philadelphia (famous for college campuses) built the Gothic Revival walls with rock from quarries around that city. Middle Wing contains a chapel with decorative carvings by sculptor Karl Sigstedt, as well as an enlarged dining hall for which Irene Sophie (wife of Irénée) du Pont, sister of the founder, gave an N. C. Wyeth mural (1938) that shows the committee studying the St. Andrew's building plans as an inspiring vision of English cathedrals rises up behind them. The wing of the 1950s includes a tower, a cloister garth with Tudor Revival arches, and a War Memorial Room honoring twenty-six alumni who died in World War II.