The century-old, family-owned firm rose 25 spots from its 2025 ranking, reflecting steady growth in its engineering and design capabilities anchored by the Mason & Hanger team, which delivers architecture and engineering services to both the federal government and private sector. As a full Engineering, Procurement, and Construction contractor, Day & Zimmermann continues to expand across the Power, Industrial, and Government markets, supporting complex projects ranging from advanced nuclear builds to renewable energy transitions and secure government facilities. The improved ranking comes amid a robust period for the design industry driven by infrastructure modernization demand and the AI boom.
