$250m glass makeover planned for Financial District tower

George Rizer for the boston globe/file (left), Gensler (right)

The owners of One Post Office Square are planning a big, glassy, re-do of the concrete Financial District tower.

Anchor Line Partners and JLL filed plans with the city this week to put a new glass facade on the 41-story office building, adding 140,000 square feet of office space, new outdoor space, and street-level retail in the process. It is also planning a new 10-story office building atop a neighboring garage on Oliver Street.

All told, it would be a $250 million-plus investment in the complex, which is half-owned by an arm of Morgan Stanley. Work would start next year, after Putnam Investments vacates about 300,000 square feet and moves to One Federal Street. Anchor Line said it’s an opportunity to refresh the nearly four-decade-old tower to compete with new buildings in the Seaport and downtown area.