Image courtesy of WS Development

WS Development is proposing changes to the next phases of its Boston Seaport project, including adding office-lab space on two parcels approved for housing and eliminating of plans for a hotel.

The amendment to the Seaport Square planned development area would expand the Seaport Common park from 36,000 to 60,000 square feet while dropping a previously-approved 30,000 square foot mixed-use building.

The changes apply to four still-undeveloped blocks within the master-planned development. They would reduce the total residential units in the Seaport Square project from 3,200 as approved in 2019 to 2,500, the original number when the project was approved in 2010, WS said in a filing with the Boston Planning & Development Agency. Approximately 2,000 condos and apartments have been completed in the project.

WS noted that the flexibility given to developers in a master-planned project allows the mix of uses to evolve over time.

“This front-loading of the residential use component of Seaport Square has already resulted in the emergence of a vibrant 24-7 district that is home to thousands of new residents alongside new retailers, employees and visitors to the district,” the filing states.

WS proposes replacing a 581,000-square-foot residential building approved for Block G with a 620,000-square-foot office-lab building. A 361,000-square-foot residential building on block L-3 would be replaced by a building containing 260,000 square feet of residential space and 150,000 square feet of office-lab space.

The L-6 block, previously approved for a 287,000-square-foot hotel, would be built out as 210,000 square feet of residential space and another 130,000 square feet of office-lab space.

The changes would result in approximately future 500 housing units, including 166 on-site affordable units.

The 30,000-square-foot mixed-use building had included plans for a Massachusetts Fallen Heroes exhibit, which will be located in a new 1,800-2,000-square-foot freestanding structure. Overall, the changes add nearly a half-acre of open space, WS said.

Multifamily development activity has decelerated in Boston over the past year, as costs escalate and developers opt for higher-rent paying life science uses. Mayor Michelle Wu campaigned on a platform of raising minimum affordable percentages in new housing developments from 13 to 20 percent, which is under review by an advisory committee.

Newton-based WS Development acquired seven of the undeveloped blocks within Seaport Square development from original master development Boston Global Investors in 2015. In 2017, the BPDA approved an increase in the project’s overall square footage to  7.7 million square feet, including 2.8 million square feet of residential space.

Editor’s note: This report has been updated to reflect the size of the Seaport Common park to 62,000 square feet.