Image courtesy of Solomon Cordwell Buenz

The owner of one of the first major life science developments in Watertown has proposed a second building that would bring the combined complex up to 290,000 square feet.

The 4-story, 104,000-square-foot office-lab building would be built on the southwest corner of the 490 Arsenal Way property. Columbia Massachusetts Arsenal Office Properties LLC proposes to build a 4-story lab building with a maximum height of 68 feet replacing surface parking.

The plans by Solomon Cordwell Buenz include a pocket park next to Nichols Avenue and creating a pedestrian path to the Watertown Greenway and Arsenal Street, according to application materials submitted to the Watertown Planning Board.

The project would add 64 subsurface parking spaces, replacing a stormwater detention chamber which will be relocated.

Originally developed by Boston-based Boylston Properties, the LINX project was one of the first to establish Watertown’s Arsenal Street as a life science growth cluster, particularly for Cambridge biotechs seeking additional research space.

The initial tenant roster included C4 Therapeutics, Aileron Therapeutics, Kala Pharmaceuticals and Addgene. In May, C4 Therapeutics leased an additional 66,052 square feet and expanded to a total of 111,611 square feet.

Greater Boston lab vacancies crept up from 2.2 percent to 2.6 percent in the third quarter, but tenant requirements still total 2.3 million square feet, according to Newmark’s Boston life science report. There are 9 million square feet of construction and conversion projects in the suburban pipeline, but a market correction could curtail many early-stage projects, the report stated.