text: Form and facade The 1916 Zoning Resolution, which required skyscrapers in New York City to have setbacks as they rose, was designed to prevent new skyscrapers from overwhelming the streets with their sheer bulk. However, these setbacks were not required if the building occupied 25 percent or less of its lot. As a result, 28 Liberty Street was designed as a single slab. While buildings with setbacks had less office space on upper floors, Chase wanted to make the upper floors as desirable to tenants as the lower floors, which led to each floor having the same area. Chase was granted a variance from the New York City Board of Standards and Appeals so that the building actually occupied 27.3 percent of the site; the extra 2.3 percent coverage allowed for an additional  on each  floor.
  The facade is composed of 8,800 plate glass panes, each measuring  tall by  wide. The glass panes are set within aluminum panels (chosen for their durability and performance) as well as vertical aluminum mullions. The aluminum panels are  thick by up to  tall and were manufactured by the General Bronze Corporation. The spandrel panels between the windows on each story are made of natural-color aluminum or black porcelain enamel. SOM chose not to use stainless steel because it was too expensive, and it did not use granite because the firm's building committee had seen the material as being too traditional.
  The building's 40 columns, sheathed with aluminum, are about  thick and are about  apart, arranged in a 4×10 grid. The columns extend from the building on its long sides, while the floors cantilever from the columns on the building's short dimensions. The columns carry much of the weight of each floor.