Image courtesy Stantec

Owners of Boston’s Dock Square Garage are switching up their redevelopment plans with a proposed redesign that would increase condo sizes by 64 percent.

Fortis Property Group received approval in June 2019 to build a 6-story addition on top of the 40-year-old garage at 20 Clinton St. and add 209 condos overlooking Faneuil Hall Marketplace and the Rose Fitzgerald Kennedy Greenway.

In a notice of project change filed with the Boston Planning & Development Agency this week, Fortis proposes reducing the condo count to 132 units along with a 12,500-square-foot increase in overall residential space. The changes would increase the average unit size from 1,165 square feet to 1,910 square feet.

No changes are sought for the garage portion of the property, which would retain 450 of the existing 698 spaces. The ground-floor retail component would shrink from 11,500 to 9,000 square feet. The on-site affordable unit count would remain unchanged at 27.

Fortis did not give a reason for the changes, but downtown luxury condo markets have been hurt by the effects of COVID-19, prompting developers to reconsider their short-term plans for high-end housing.

In July, the BPDA gave Millennium Partners permission to shrink the housing portion of its $1.3 billion Winthrop Center skyscraper at 115 Federal St. after developers said they were unable to obtain financing. A July report prepared by consultants Ernst & Young said the lending environment for luxury condo towers has evaporated.

At the same time, a glut of condo listings has emerged in neighborhoods such as Back Bay, South Boston and South End.

Brooklyn, New York-based Fortis estimates hard construction costs at $120 million. Fortis bought the property from the original developer in 2017 for $170 million.