Day & Zimmermann: Detailed Company Information & Corporate Profile
Summary
Day & Zimmermann is an independent construction and engineering firm that began in 1901. Based in Philadelphia, Pennsylvania, the company operates throughout the Delaware Valley region under SIC code 6500.
With more than ten thousand employees and annual revenue between one and five billion dollars, Day & Zimmermann delivers services in construction, engineering, staffing, security, defense, operations and maintenance for a variety of large‑scale projects.
The leadership team drives the organization’s strategy, featuring professionals such as Melissa Cadet, Talent Acquisition Coordinator; Mark Mangiamele, Scheduling Specialist; Joshua Harper, Strategic Supply Chain Specialist; Tim Ridewood, Project Controls Manager; Maggie Fisher, Project Controls Manager; and James Boulanger, Director of Operations.
| Day & Zimmermann Website | dayzim.com |
| Social Links |    |
| Phone Number | 215-299-8000 |
| Industries | |
| Day & Zimmermann Headquarters Address | 1835 Market St, Philadelphia, Pennsylvania, 19103 US |
| Company Size | 10000+ employees |
| Specialities & Services | Construction, Engineering, Staffing, Security, Defense, Operations & Maintenance |
| SIC Code | 6500 |
| DMA Code | Delaware Valley |
| Founded | 1901 |
| Estimated Annual Revenue | $1B - 5B |
| Operating Status | Independent Company |
| Updated: | 2026-09-10 |
Competitors
Name | Founded | Type | Employees |
|---|---|---|---|
| 1978 | Privately Held | 250 - 500 | |
| 06/1962 | Privately Held | 25 - 100 | |
| 1935 | Privately Held | 1.0K - 5.0K | |
| 1957 | Privately Held | 1.0K - 5.0K |
Subsidiaries and Affiliated Companies
Estimated Website Traffic
The chart shows a decline in traffic to the dayzim.com website. In August, traffic decreased to 17563, compared to 17728 in the previous month. The highest traffic in 2026 was recorded in January, reaching 23742 visits.
Workforce Turnover
Number of employees switched from or switched to
Departmental sample breakdown
Length of Employment
Day & Zimmermann's workforce includes employees across a wide range of tenure levels.
5% have been with the company for 1 to 2 years7% have been with the company for 3 to 4 years10% have been with the company for 5 to 7 years13% have been with the company for 8 to 10 years65% have been with the company for more than 11 years
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Day & Zimmermann Corporate Information: FAQ
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