Dan Gilbert has added another Woodward Avenue building to his ever-growing collection of downtown Detroit real estate.

The billionaire founder and chairman of Detroit-based Quicken Loans Inc. and Rock Ventures LLC has finalized the purchase of the Fowler Building at 1225 Woodward Ave. for an undisclosed price.

Its previous owner, an entity affiliated with New York-based Sequoia Property Partners, put it on the market late last year for $22 million, or $396.40 for each of its 55,500 square feet. Sequoia paid just $700,000, or $12.61 per square foot, in 2012.

An email was sent to a representative of the previous ownership group seeking comment.

The first floor of the building is expected to be converted to retail while its upper seven floors are slated for office or residential conversion, said Jim Ketai, chairman of Gilbert's Bedrock LLC real estate development, ownership, management and leasing company. The building will be cleaned out starting "right away" and the redevelopment will start "immediately," Ketai said.

It has been vacant for around two decades.

"I have been eyeballing it for a long time saying, 'I wish the rest of that block and these three blocks would be occupied and look good,' " Ketai said Thursday morning. "To me, with everything else going on on Woodward with the buildings we have brought back to life and the Hudson's and Monroe developments happening, it was necessary to add this to complete the whole thing."

Bedrock is working on the $909 million development of what is expected to be the state's tallest building on the site of the former J.L. Hudson's department store and the $830 million Monroe Blocks development near the Quicken headquarters.

The Fowler renovation budget has not yet been determined, but Ketai said "it will be a lot of money, a big investment."

"A lot of work needs to be done. The building is not in very good shape. It's somewhat similar to the other buildings, like 1201 and 1207 (Woodward)," Ketai said. "All the core and shell needs work, we'll repair the facade and put in new infrastructure and windows."

After being built for an estimated $150,000 (about $4 million today), the Fowler Building opened in 1911 as the home of Kline's Ladies Wear, which was housed there until 1958, according to city historic documents. It was designed by the architecture firm Donaldson & Meier.

The Fowler was one of the few buildings along the Woodward corridor south of Grand Circus Park that didn't bear Gilbert's fingerprints, either through ownership or a master lease for the retail space.

Others are the Coleman A. Young Municipal Center (Detroit-Wayne Joint Building Authority), the Himelhoch Apartments (American Community Developers), the David Whitney Building (Roxbury Group), the Bleu Detroit building at 1540 Woodward (Nick Abraham), the Guardian Building (Wayne County), 511 Woodward Ave. (Wayne County) and One Kennedy Square (Redico LLC).

Bedrock and Farmington Hills-based Keystone Commercial Real Estate LLC were the brokerage firms on the transaction. An architect and contractor have not yet been selected for the renovation.