While attending a management conference in 1989, Doug Woods learned from his boss that he would never rise high enough to lead the construction firm he’d worked at for 15 years. So he and two co-workers, Peter Nosler and Ron Davidowski, resolved to quit and start their own company—one that prioritizes employee happiness.

Since its founding in July 1990, DPR Construction (named for Doug, Peter, and Ron’s collective monogram) has encouraged its workers to take the lead. The founders decided from the beginning that the new firm would be employee owned via a phantom stock program that ties compensation to company profits and individual performance. They even eliminated titles from business cards. And to prevent power struggles, the founders devised a buy-sell agreement that would bar shareholders from divesting stock to anyone outside the company. Everyone with equity is required to sell his stake back to the company beginning at age 60. Now celebrating its 25th year, the company has helped build projects ranging from Facebook’s data centers to R&D labs for universities and pharmaceutical companies, and has opened 20 offices from Washington, D.C., to San Francisco. Last year the company acquired Atlanta-based Hardin Construction, and revenues hit a record $2.6 billion.

Already, two of the founders—Nosler and Davidowski—have relinquished their stakes in the company, as agreed, though they remain active as directors. Woods’ ownership, too, is set to expire at the beginning of 2016.

“We have the ability—no matter who you are in the organization—to be able to provide input and impact and have your thoughts and ideas considered,” says Brian Gracz, a project executive who has been with the company 17 years.

Because of an open floor plan and no titles, clients tend to have difficulty figuring out who’s the boss. In a sense, that’s because everyone is in charge, says Peter Salvati, who sits on the company’s management committee.

Each office also features an onsite bar. Employees (including DPR’s contracted construction workers) congregate at these mini-cantinas to celebrate achievements like winning or completing projects, to mingle with customers, or to unwind during happy hour. At the San Diego site where Gracz is based—one of DPR’s three net-zero offices—employees belly up to a surfboard-shaped bar cut from dark Hawaiian koa wood. In D.C., colleagues lounge at a modern bar with a granite finish. Each site has a local ambience.

“When we started out, the bottles weren’t quite as good,” Woods says, “but we’ve grown to like good wine, and we enjoy getting together.” Even as DPR has matured, the culture remains the same.

This story is from the December 1, 2014 issue of Fortune.