Two additional floors for Huntington Ave. tower approved

New Construction New Developments Fenway-Kenmore
A rendering of the project at 252-258 Huntington Ave.
A rendering of the project at 252-258 Huntington Ave. Stantec via BPDA

Two more residential floors will be added to the 400-plus unit apartment building slated to rise on Huntington Avenue, part of a project that will also redesign the longtime home of Huntington Theatre Co.

The Boston Planning and Development Agency signed off Thursday on a notice of project change filed last month by QMG Huntington Limited Partnership that sought permission to add 24,710 square feet of space for 20 more apartments, raising the total for the 362-foot-tall tower to 446 units.

The additions, however, would not change the overall height of the 34-story complex, since developers will gain the extra space by reducing floor-to-ceiling measurements from the third floor on up, project officials said.

The change tweaks a development that will both alter the Fenway skyline and write a new chapter for the theater company, which has called its namesake avenue home for more than 35 years.

–Stantec via BPDA

Developers bought the historic playhouse from Boston University for $25 million in 2016, and later struck a deal with the company to allow it to own its theater while also agreeing to a 100-year, low-cost lease for two floors of the adjacent tower.

While the company is undertaking renovations of the theater on its own, the 14,000 square-foot addition next door will house a lobby and other programming space, plans show.

The BPDA approved the project in late 2017.

Developers say the theater company does not have any issues with the proposed changes, which will also bring in three more affordable residential units to the site. The floor-to-ceiling heights for the space to be occupied by the theatre company would not be affected, according to the plans.

“All other community benefits would remain the same,” officials wrote in the notice.

Construction has fallen behind the initial schedule, but developers said they anticipate work to begin later this year.

Subscribe to the Globe’s free real estate newsletter — our weekly digest on buying, selling, and design — at Follow us on Facebook and Twitter @globehomes.