Developers behind the 110 N. Wacker office tower filed a zoning amendment to increase the square footage of the building, which if approved will bring the total floor space to 1.6 million square feet. According to Curbed Chicago, the Bank of America-anchored building is seeking an increase of 100,000 square feet.

In January, Dallas-based Howard Hughes Company and Chicago-based Riverside Investment and Development proposed the 800-foot tower to replace the low-rise, 200-square-foot General Growth Building. The tower is the tallest building proposed in Chicago since 1990 that would be exclusively office space.

The latest adjustment to the building proposal includes a slightly different facade to make up for the added square footage without having to adjust the height. The glass riverfront skyscraper ditched its three-tier facade for a two-tier design. The building will still reach 800 feet tall and 51 stories.

The team was originally hoping to get started on construction as early as next month, but the federal government launched a Section 106 Historic Property Review to consider any adverse effects the building could have on the existing General Growth property. The U.S. Army Corps of Engineers stalled the project because it requires demolishing an architecturally significant building.

Developers already got city approval for the initial square footage, but are still waiting on approval from the Army Corps. Approval is needed largely because the project requires building a stormwater outfall structure that will allow rainwater to flow from the tower’s roof into the river.

The current building was also considered by the Illinois Historic Preservation Agency back in August as being eligible for the National Register of Historic Places. Developers have proposed “conducting a survey of the structure and documenting it,” according to the Chicago Tribune.