For more than a century, the Nathan Clifford School in the city’s Oakdale neighborhood provided an education to generations of Portlanders.

Now, the former elementary school, after a $7 million renovation, has reopened not as a school, but as a residential complex offering market-rate rents to city dwellers who can afford to pay between $1,600 and $2,200 a month for 17 two-bedroom and four three-bedroom units. There is one single-bedroom unit.

The school’s rebirth will be celebrated at 11 a.m. Tuesday when the developer and city officials gather at the former school on Falmouth Street to talk about its new life, its public amenities and the importance of preserving the building’s historic features. The school is listed on the National Register of Historic Places.

“We are really excited about the fact that there will be housing created in that building,” said Portland Mayor Michael Brennan, who plans to attend the ceremony. Brennan said he is glad the school building could be preserved, though some residents wanted to see it reused for educational purposes when the city sought development bids in 2013. “It is an important, historic landmark for the city of Portland.”

Brennan said that Developers Collaborative, a Portland-based firm, acquired the Nathan Clifford School from the city in 2013 for $1.

In exchange for the low sale price, the developer agreed to set aside 14,000 square feet of land around the school for a public park and neighborhood playground, Brennan said.

Kevin Bunker, one of the founding principals of Developers Collaborative, said the school renovation took place in 2014, with the first tenants moving in during early February. Bunker redeveloped the school along with his business partner, Richard Berman. The complex is being called the Nathan Clifford Residences.

Bunker said all 22 units have been leased.

“When we came on line there was nothing available in the Portland market. The (rental) market here was starved,” Bunker said.

Most of the tenants are couples and are either younger or older professionals, Bunker said.

“The one thing they all have in common is dog ownership,” he said.

Jessica Grondin, the city’s spokeswoman, said in a news release that the Nathan Clifford School has been “carefully renovated to maintain its original historic school elements including floors, blackboards, built-in closets and school murals.”

Grondin said that in addition to preserving the building’s historic features, the project offers modern amenities, including a gym, library and garden plots.

Bunker said the renovation project tried to preserve the school’s historic elements. Each apartment contains a slate chalkboard. A 1930s chalk mural drawn by an unknown artist has been sealed inside a glassed-in wooden case and displayed in a public area.

“The big win here was for the neighborhood. Keeping that building was so important to them,” Bunker said. “Generations of Portlanders have gone to that school.”

Bunker estimated that the development will generate about $90,000 a year in property tax revenues for the city.

The Nathan Clifford School closed in 2011 when students began attending the new Ocean Avenue Elementary School. The residential building is located a short distance from the University of Maine School of Law and is within walking distance of Hadlock Field, Back Cove and downtown Portland.

The school was designed by renowned Portland architect John Calvin Stevens. It was named after U.S. Supreme Court Justice Nathan Clifford. His grandson – also named Nathan Clifford – served as Portland’s mayor when construction on the school started in 1906.