For the expansion of a 1970s-era kit house on the East End of Long Island in Southampton, New York, architect Paul Masi looked to the structure’s muscular prefabricated components for design cues—a choice that ultimately informed the look and feel of the addition’s bold new kitchen, completed last year.

“We liked the idea of an expressed structure—you see it, you read it, you understand how the building stands up,” says Masi, a principal of Bates Masi + Architects, based in nearby Sag Harbor.