The 1916 Zoning Law The New York City Zoning Resolution of 1916 restricted the use, height, and bulk of buildings, applied by "districts" or "zones." Its provisions for segregation of uses -- commercial, residential, and unrestricted -- followed the approach of several American cities in the first decade of the century. Its important innovation was the concept of the "zoning envelope," a formula that restricted the maximum mass that could be constructed on a given site. Designed to protect some measure of light and air for Manhattan's canyons, the law required that after a fixed height above the sidewalk (usually 100 or 125 feet), a commercial building must be stepped back within an "angle of light" plane drawn from the center of the street. A tower of unlimited height was permitted over one-quarter of the site. The resulting "setback" or "wedding cake" massing, with or without a tower, became the characteristic form for the New York skyscraper from the 1920s through the 1950s. By the 1930s, the zoning law had transformed Lower Manhattan into a landscape of pyramidal masses and pinnacle towers.
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