JLL’s Boston office is about to get a pricey facelift.  Developers hope to start work in 2018 on a $250M upgrade on the concrete facade at One Post Office Square. The modernization project would reclad the 41-story building with glass and expand it from 853K SF to 1.1M SF, the Boston…

Developers hope to start work later this year to replace the pre-cast concrete exterior of One Post Office Square with a glass facade as part of a $250 million office tower and garage modernization project.

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…