DETROIT ? By October, Quicken Loans will start moving another 2,000 employees to Detroit from the suburbs, nudging downtown closer to what Quicken founder and Chairman Dan Gilbert calls the tipping point for revitalization.

Gilbert told the Detroit Free Press editorial board Monday that most of those workers will move into the Chase Tower, a longtime bank headquarters on Woodward on Campus Martius Park that he bought this year.

Others will move into the First National Building, a 1922 skyscraper across Woodward from the Chase Tower that Gilbert also acquired this year.

The moves will bring Quicken’s downtown work force to nearly 4,000. Combined with 3,000 new Blue Cross Blue Shield of Michigan workers moving downtown, as well as more from DTE Energy and other employers, the moves promise to shake up and enliven the long-depressed downtown scene, the Free Press reported.

“So 2,000 more people, that’s a small city, right?” Gilbert said during the meeting at his offices. “I can’t wait to look out the window in November, December, next spring, and see what happens around this area.”

Moving workers downtown is only part of the dramatic change that Gilbert foresees for downtown. He’s also working to attract retailers to downtown’s long-vacant storefronts.

Even with several buildings already in his portfolio, Quicken Loans founder and Chairman Dan Gilbert said Monday that he’s not done shopping for downtown real estate.

“We’re opportunistic. There are always things in play,” Gilbert told the Free Press editorial board during a wide-ranging 90-minute meeting at his headquarters in the Compuware building downtown.

“We’re always in discussions,” he added. “I would say we’re probably not done.”

Nor is Gilbert satisfied with the state of the four buildings that he has bought downtown. He and his top aides want all four — the Chase Tower and the First National, Dime and Madison Theatre buildings — to get dramatic makeovers, with new first-floor retail and modern signage.

“This whole idea of modernizing a lot of things down here, we definitely are looking at that,” said Matt Cullen, president of Gilbert’s Rock Ventures, Gilbert’s venture to invest downtown. “We want to have that kind of energy down here.”

Gilbert said he’s buying so much real estate to have space available for new entrepreneurial firms that he hopes will follow his move to downtown. And if his investment in downtown real estate — which Cullen has said eventually will top $100 million – pays off handsomely someday, that’s good, too.

“There’s no conflict in doing good and doing well,” Gilbert said.

Quicken moved its first 1,700 employees downtown from the suburbs in August 2010. In just 13 months, downtown has gotten livelier, Gilbert said.

Quicken also is one of five major employers offering incentives for employees to live downtown.

a>>