For 125 years, Day & Zimmermann has helped shape the world as we know it. Founded just after the turn of the century, our story runs alongside our nation’s history, through innovation and industry, challenge and change.
As America celebrates its 250th anniversary, we mark a milestone of our own: a company that has been here for half the life of the country, evolving with it, strengthening it, and helping move it forward.
Pictured at the Philadelphia Quartermaster Terminal on May 24, 1914, are (L-R) Nicholas Roosevelt, John Zimmermann, Charles Day, and Daniel Bates. Standing before the firm’s early logo, these leaders directed the company through a transformative era of national infrastructure and defense.
Captured on November 26, 1951, this view of the Gatun Locks highlights the massive infrastructure Day & Zimmermann helped bring to life. The firm’s early expertise was cemented here when co-founder Charles Day was appointed by President Roosevelt in 1906 to oversee construction progress for this global engineering marvel.
In November 1906, President Roosevelt traveled to the Panama Canal Zone—the first time a sitting U.S. President had left the country—to witness the construction progress first-hand. Following this trip, he sought expert technical advice to address the immense engineering and organizational challenges facing the project.
Charles Day, a young engineer known for his "betterment reports" and industrial efficiency expertise, was selected to investigate and report on the progress of the canal's construction.
This high-profile appointment helped establish the firm's reputation for large-scale engineering. Shortly thereafter, in 1907–1908, the firm (then known as Dodge & Day) was directly involved in the construction of the Gatun Lock system.
During this project in 1908, the firm set a world record for hauling concrete, a feat that brought significant attention to the company within the construction industry.
During World War I, Philadelphia City Hall stood as a powerful symbol of the American home front's mobilization. Draped in patriotic banners declaring "Food Will Win the War" and urging citizens to "Buy U.S. Government 4% Bonds," the building served as a backdrop for a city transformed into an industrial powerhouse.
For Day & Zimmermann, a firm deeply rooted in Philadelphia, this era was defined by intense service to the United States. While citizens in the streets committed to conservation and financial support, the firm applied its engineering expertise to critical defense projects across the city, from the Navy Yard to the massive Quartermaster Terminal, helping to fuel the progress that would ultimately secure victory.
As the lead architecture and engineering firm for NASA’s Flight Dynamics Research Facility (FDRF), Mason & Hanger, a Day & Zimmermann company, was responsible for the complex design of the first major wind tunnel built at Langley in decades. The team engineered the specialized infrastructure required to house the facility’s vertical air-loop and massive fan drive systems, seen in the image pictured on the left. By integrating high-precision mechanical requirements with a 25,000-square-foot structural footprint, we provided the technical backbone for a facility that now tests the stability of everything from urban air mobility drones to Artemis-era spacecraft.
Now, as we look to the future, our work is far from finished. The next chapter calls for bold thinking, resilient solutions, and an unwavering commitment to creating a better world. At 125 years strong, Day & Zimmermann, a proud Philadelphia-based company, is ready. Not just committed to building what’s next; but dedicated to leading the way as we help to build a better future for our customers, employees, communities, and the world.
