Detroit's planned tallest new building may no longer in fact be the city's tallest when it opens on the old Hudson's site in a few years.

Officials from the Bedrock real estate firm said Wednesday that switching the programming of the planned skyscraper tower on the Hudson's site from all residential to partly a hotel may change the height of the tower, depending on the needs of whatever hotel operator is chosen.

"I think it's fair to say it's open," Joe Guziewicz, vice president of construction for Bedrock, said Wednesday during a media briefing and hard hat tour of the Hudson's construction site.

The planned height has evolved over the past two years, from an initial estimate of 734 feet (just a few feet higher than the Renaissance Center), then perhaps 800 feet tall, and finally about 912 feet. But all the previous estimates were viewed as approximate until a final program was fixed.

Bedrock now estimates that the Hudson's site project will open in 2023, about a year later than was estimated at groundbreaking in 2017.

Since the groundbreaking, construction work continues in what crews call "the hole," a 40-foot-deep excavation. The project is actually two buildings, a midrise "block" that will be mostly office and retail, and the soaring residential/hotel skyscraper.

Asked whether the tower portion of the project, at one point projected to rise about 100 feet taller than the Renaissance Center, may be only half as tall as earlier projected, Guziewicz said, "It's a tough question to answer. Do I think it's going to be half the size? My gut reaction is probably not. Is it going to be the tallest building? Possibly. ... Until we settle with an (hotel) operator, it's just going to be really difficult to project what that final height's going to be."

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During a wide-ranging discussion of Bedrock's four "transformational" projects mapped by business Dan Gilbert in the heart of downtown Detroit, Guziewicz and other Bedrock officials also said:

With the switch of the Hudson's tower to partly hotel, the idea for a public observation deck at the top has been scrapped, Guziewicz said. Building the viewing platform would have required one too many elevator shafts that would have cut down on usable space lower in the tower.

The office, retail and residential mixed-use project on the Monroe Block is undergoing design revisions. Actual construction, which was to have been underway by now, is scheduled to start in early 2020.

Bedrock's addition to the rear of the One Campus Martius building, formerly the Compuware headquarters, is about 60% complete. The extension should be ready for occupancy late this year and will include office and rentable event space.

Renovations continue to the historic Book Tower, a vacant office tower that dates to the 1920s. Exterior restorations are nearly complete and interior renovations are ongoing, with completion scheduled for 2022.

At the Hudson's site itself, construction crews have completed about 75% of the caissons, or deep-penetration foundations that will anchor the building. By next spring, Bedrock officials said, passersby should see steel structures beginning to rise above street level.

Guziewicz said that the widely discussed challenges in development in Detroit these days, including rising costs of materials and labor, have challenged the Bedrock projects, too. But he said the four downtown projects — Hudson's site, Monroe Block, Book Tower, and the One Campus Martius extension — are all going ahead.

"These buildings are absolutely needed and desired," he said.

Contact John Gallagher:313-222-5173 or gallagher@freepress.com.Follow him on Twitter@jgallagherfreep. Read more on business and sign up for our business newsletter.