Joined by neighborhood associations, developers and city officials, Mayor Michelle Wu marked the start of construction Thursday on a conversion project that brings the total number of housing units begun under the city's office-to-residential program to more than 100.

Since the tax incentive program launched less than two years ago, developers have filed plans to convert 620K SF of office space into 780 units of housing across the city.

With the latest start, a 77-unit project at 263 Summer St., there are four projects under construction totaling 141 units. The other conversion projects underway are at 129 Portland St., 615 Albany St. and 281 Franklin St.

"I know the need is immense, and when we talk about the housing crisis in Boston and in Greater Boston, it's not in single units or dozens or even hundreds of units," Wu said at 263 Summer St. "We are talking about hundreds of thousands of units, but every little bit makes a difference."

The project is being developed by Burns Realty & Investments, led by founder Adam Burns, and it includes 15 income-restricted units. Burns acquired the eight-story former office building for $17M from Nuveen Real Estate in 2024.

"Thanks to this program and the mayor's support, the permitting process moved forward swiftly," Burns said. "This means vital housing being delivered to Boston years sooner than it otherwise would have."

The Summer Street project is the second conversion development Burns has worked on, with the first set to open this fall at 281 Franklin St.

The Franklin Street project, which consists of 15 apartments, was the first to receive approval through the city's conversion program. Burns was also the first developer to receive financing, securing a $5.1M loan from Rockland Trust for the Franklin Street property.

"This program is more than a policy. It's a forward-looking solution," Burns said. "It reimagines our urban core, it activates our neighborhoods, and it helps build a livable, equitable and resilient Boston for future generations."

The Summer Street project was greenlit in December 2024 by the Boston Planning Department and received community support, especially after agreeing to keep the Boston Wharf Co. and Industrial Real Estate sign on the top of the building intact.

The project is set to deliver in September 2026, Burns said.

"We'd like to welcome you to our corner of South Boston," Fort Point Neighborhood Association Board Member Tom Ready said at the event. "With this project, this will be the 16th building in our neighborhood that's been repurposed from that traditional loft and manufacturing base use — the very first to take advantage of this program."

The other two office-to-residential conversion projects underway are 129 Portland St. in Bulfinch Triangle and 615 Albany St. in the South End. Developer Greg McCarthy is behind both projects, which total 49 units.

Boston officials launched the office-to-residential Payment in Lieu of Taxes Program in October 2023, incentivizing developers to pursue conversion projects for an average tax reduction of 75% of the standard tax rate for up to 29 years.

The program was then extended in 2024, and this year, the Wu administration expanded it to include employers and institutions.

The program is set to expire at the end of this year, but Wu said she would like to extend it further if there is demand from the real estate industry to pursue more projects.

"If there's more interest, developers should reach out and let us know," Wu said. "That would certainly factor into whether or not we expand and extend it."