HAVERHILL - The Catholic Archdiocese of Boston is moving forward with plans to renovate the Hayes Building into 57 apartments, marking another step in the revitalization of downtown.

The Hayes Building project is the first development to apply for a permit in the 40R zone - a 53-acre area downtown where building housing is faster, easier and potentially less costly than outside the zone. The purpose of the 40R zone was to make it easier to redevelop vacant old factory buildings, said William Pillsbury, the city's planning director.

Archdiocese officials talked in December about the possibility of putting housing in the building. The project is now being put forward by a nonprofit development arm of the archdiocese, the Planning Office for Urban Affairs. The initial application has been filed with City Council, and a public hearing will be April 24.

The $18 million project brings the number of newly built, under construction or proposed homes in downtown Haverhill to 845 - split among eight projects and seven developers.

Mayor James Fiorentini said he lobbied the Catholic agency to build condos instead of apartments but was unsuccessful. He still thinks it is a good project.

"It's certainly exciting to see an old factory building to be reused," Fiorentini said.

William Grogan, chief operating officer for the Planning Office for Urban Affairs, said building apartments allows his organization to get state and federal tax credits that condos would not bring.

He also said the apartments were more feasible.

"Given the market ... redevelopment in rental housing is more feasible," Grogan said of why the units will not be condos.

The initial plans for the project include 57 apartments, 24 of which will be rented to lower-income tenants at 14-44 Granite St. The plans call for 11 one-bedroom units and 46 two-bedroom apartments.

Three units on the first floor will be filled with retail stores such as a book dealer and coffee shop, both of which are being considered, Pillsbury said.

Grogan's agency, described on its Web site as "a self-sustaining social justice ministry of the archdiocese," has built about 2,200 units of mixed-income housing in Massachusetts since it was established in 1969 by the late Cardinal Richard Cushing.

In exchange for creating the 40R zone, the state will pay the city $600,000 in upfront cash and an additional $3,000 per new residential unit built in the district - potentially bringing $171,000 for the Hayes Building project.

The mayor has said his ultimate goal is to replace the city's early-20th-century industrial downtown with "a modern, people-center, urban village."

The archdiocese is glad to build in downtown Haverhill, Grogan said.

"The city ... has all shown a really strong commitment to revitalizing the downtown area," Grogan said. "We're excited to be a small part of that effort."

PG1 BOX

The Hayes Building project

Where: 14-44 Granite St.

Project: Renovate old factory building into 57 apartments

Cost: $18 million

Square footage: 94,410

Retail stores: three

Developer: Planning Office for Urban Affairs, an arm of the Archdiocese of Boston