PHILADELPHIA, PA —May 8, 2026 — Day & Zimmermann (D&Z), the century-old, family-owned provider of construction and maintenance, engineering, staffing, and defense solutions, has once again been recognized as one of the nation’s leading design firms. According to the 2026 Top 500 Design Firms list recently released by Engineering News-Record (ENR), Day & Zimmermann is ranked No. 348.
This year’s placement represents a significant climb for the company, rising 25 spots from its No. 373 ranking in 2025. The annual ENR Top 500 list ranks the largest U.S.-based design firms, both publicly and privately held, based on design-specific revenue from the previous year.
“Climbing the ranks in ENR’s Top 500 Design Firms underscores the progress we’re making expanding our capabilities as a full EPC partner,” said Jason Dunaway, President of D&Z’s Maintenance and Construction division. “By connecting engineering and construction expertise, we’re delivering smarter, end-to-end solutions that meet increasingly complex customer needs and strengthen our reputation for project execution excellence in the markets we serve.”
D&Z’s engineering and design services, anchored by its Mason & Hanger team, provide essential architecture and engineering (A/E) services to the federal government and private sector. Combined with D&Z’s growth as an Engineering, Procurement, and Construction (EPC) contractor providing full project delivery, the company is well positioned to support clients across the entire project lifecycle. The firm continues to expand its footprint in the Power, Industrial, and Government markets, investing in integrated EPC delivery models and leveraging its "first-time quality" approach to support complex projects ranging from advanced nuclear builds and renewable energy transitions to secure government facilities.
“Advancing in ENR’s Top 500 Design Firms ranking is a direct reflection of the expertise, dedication, and consistency of our people. I want to thank our employees across Mason & Hanger, Day & Zimmermann’s A/E Group, whose commitment to quality and technical excellence drives everything we do. Our work embodies our purpose of Building a More Secure World. This recognition is a testament to the impact we deliver for our clients every day.” Ben Lilly, President, Mason & Hanger
The 2026 ENR report highlights a robust period for the design industry, driven largely by an "AI boom" and continued demand for infrastructure modernization. D&Z’s improved ranking underscores its ability to navigate these market shifts while maintaining its legacy of excellence as a leading "M" (Multi-disciplined) firm.
For more information about Day & Zimmermann and its engineering services, please visit www.dayzim.com.
About Day & Zimmermann
When you’ve been around for more than a century, you learn a thing or two. At Day & Zimmermann, we take our lifetime of experience and make things better. Our 32,000 employees help bring big ideas to life every day. We’re pushing the boundaries of innovation in construction & engineering, operations & maintenance, staffing, and security & defense. And that’s not all. Did we mention that we have 900+worldwide work locations with $2.9 billion USD in annual revenue? We put people to work, we protect American freedoms, and we help our customers power and improve the world. We do what we say®. www.dayzim.com