The New Canaan Housing Authority is seeking to increase the number of affordable housing apartments.

The Board of Selectmen unanimously approved Tuesday a request from the commission to appropriate up to $500,000 from the Affordable Housing Trust Fund for engineering design costs for the new units.

Charles Berman, chairman of the Housing Authority, said the new units will be built on the same site of the Millport Apartments on Millport Avenue. The 18-unit complex and the adjacent 40-unit Mill Apartments are both managed by the authority and house low-income families.

The project would include the demolition of Millport's 18 existing units, as well as its four condominiums and build a new complex on the same site.

At the meeting, Berman said the project could result in a total of 70 apartments at the same space, but he later said the project is in the planning stage and that he would have a better estimate in a few weeks.

He said "there's a lot of planning that goes in" before a final number is reached.

Berman said the families living in the complex would be relocated for about a year while construction takes place.

The engineering work should also take about a year, Berman said. After the plan is completed, the Housing Authority would need to work with the Planning and Zoning Commission and the U.S. Department of Housing and Urban Development and seek private contributions and government grants to fund the project.

Berman said the project is in line with the New Canaan Housing Authority master plan and that the apartments would still be only two stories high.

First Selectman Robert Mallozzi said the expansion would be "phenomenal."

"Most importantly, this keeps us on that path that we want, (which is) our commitment to affordable housing in our community," Mallozzi said.

Mill Apartments underwent a similar expansion in 2011 for a cost of nearly $8 million.

The Housing Authority is scheduled to meet Tuesday, May 20, when more details on the project may be available., 203-330-6582, @olivnelson