Local development group Wharton Street Lofts signed a sales contract for the property recently, but real estate agents would not comment on details of the contract.
The group plans to turn the school into 48 apartments, said developer Leo Addimando, who represents the group.
"We're trying to build nice apartments - the same apartments you might see in Center City," he said Thursday. "We want nice finishes, granite countertops, stainless appliances, in a submarket that doesn't have a lot of apartments or larger apartment buildings."
A one-bedroom unit in the newly christened Wharton Street Lofts would likely rent for $1,000 to $1,500 a month. A two-bedroom would go for $1,500 to $2,000, Addimando said.
Representatives from the archdiocese were not available for comment on the sale Thursday afternoon, but Addimando said he believed Annunciation was the first of the Catholic grade schools vacated this year to be proposed as an apartment building.
"It's my opinion that you will see a number of schools in gentrifying areas redevelop into residential [housing]," he said. "Residential is a very easy use to convert a school into, with the classrooms becoming apartments. And they generally have large parking lots, which helps with parking issues."
Members of the Passyunk Square Civic Association who met Tuesday night with Addimando to hear his plans for the building, said they were pleased that the neighborhood would get new development and that Annunciation would not sit vacant for long.
"We welcome this new development - we don't want the building to sit empty. We're very fortunate to live in a neighborhood where that doesn't happen very often," said Cassie Knox, chairwoman of the civic association's communications committee.
Some residents at the meeting expressed concerns about parking - Addimando and his group have indicated they will build 37 spaces for their 48 units - but Addimando said he expected just one in two tenants would likely require a parking space. "City planners and the city government, in partnership with private developers, spent five years to create a zoning code to take us into the future. One car for three apartments is where things are headed," he said.
Addimando expects to begin moving tenants into Annunciation by the first quarter of 2014 - just over two years after parents and parishioners fought to save the school, which had a 45 percent enrollment rate when it closed this year.
Parishioners took up the fight after the archdiocese announced in February that Annunciation would merge with St. Nicholas of Tolentine. They submitted appeals and launched an online petition that collected 239 signatures. Their appeal failed, however, and both schools combined as St. Anthony of Padua Regional Catholic School in the fall.
Addimando said he had not heard complaints from neighbors who had held out hope that Annunciation could be saved. His group is obtaining zoning permits for the building and will come back to the civic association for another community meeting next month.
"Our meeting Tuesday was an informative meeting to set people's mind at ease a little bit. The process takes a few months from the start to the end. Hopefully, we'll come to a happy place with the neighbors," he said.
Contact Aubrey Whelan at 215-854-2771, email@example.com, or follow @aubreyjwhelan on Twitter.