The center of downtown Lawrence is about to get taller.

Construction crews are expected to soon begin work on a seven-story, $10 million building that will house 55 apartments and a mix of retail and office space at Ninth and New Hampshire streets.

“I think in the next 30 days we’ll be digging a basement,” Lawrence developer Doug Compton said Monday.

The building, slated for the southwest corner of Ninth and New Hampshire streets, would be nearly as tall as the adjacent U.S. Bank Tower. The Journal-World reported in April that a group led by Compton was exploring the project. On Monday, Compton said he had begun pre-leasing the building and was finalizing details on bank financing.

“From what we’ve heard, it seems to be exactly what everybody who has any interest in downtown says they want to see,” Compton said.

The project would include 55 apartment units on the top five floors of the building. The second floor is set aside for a single office user, with the headquarters for Compton’s First Management Inc. being the most likely tenant. Compton said he’s close to finalizing a lease with a health club to occupy the ground-floor space. A small coffee shop and wine bar also would be included on the first floor.

The apartments will be a mix of 10 studio units, 35 one-bedroom units and 10 two-bedroom units. Parking for the apartments will be provided in the existing city-owned parking garage, which will be slightly modified to connect to the new building.

Compton said the project will be geared to attract a variety of tenant types, including retirees, young professionals, graduate students and downtown employees.

“The dynamics of downtown have changed a lot over the last dozen years,” Compton said. “The Hobbs Taylor Lofts got a lot of people thinking about living in downtown. People’s attitudes about that have really changed.”

Unlike the Hobbs Taylor project — a multistory condo development at Eighth and New Hampshire — all of the living units in Compton’s building will be rentals.

Compton said he thinks that may be the next big trend for downtown. He said that if the project goes well, he’ll consider transferring the concept to other properties he owns downtown. Specifically, Compton said, the former Strong’s Office Supply building in the 1000 block of Vermont Street could be a candidate for a multistory, mixed-use building.

Other developers also may start eyeing other large, underdeveloped sites in downtown.

“There is a lot of potential for this, but you have to have someone put their toe in the water and see what the temperature is,” said Bill Fleming, an architect with Treanor Architects, which also is involved in the project. “That’s what this will do.”

The Ninth and New Hampshire project already has most of the city approvals needed to start. The property long has been zoned for downtown commercial development, which allows for residential uses. The building design has won approval from the city’s Historic Resources Commission, and city planners are close to finalizing the site plan for the property, said Scott McCullough, the city’s director of planning.

Several downtown leaders also have endorsed the project. Joe Flannery, president of Weaver’s Department Store, said additional living units most likely will be the best way to add new types of retailers to downtown, like a drug store or even a grocer.

The size of the building also has not caused business leaders to balk.

“We’ve known for a while that if downtown is going to grow it would grow vertically,” Flannery said. “We’re expecting to see more of that. This will just add another landmark for downtown.”