The Flatiron Building s a triangular 22-story steel-framed landmarked building and is considered to be a groundbreaking skyscraper.
The design was by Chicago’s Daniel Burnham as a vertical Renaissance palazzo with Beaux-Arts styling.
Once construction of the building began, it proceeded at a very fast pace. The steel was so meticulously pre-cut that the frame went up at the rate of a floor each week. By February 1902 the frame was complete, and by mid-May the building was half-covered by terra-cotta tiling. The building was completed in June 1902, after a year of construction.
Building the Flatiron was made feasible by a change to New York City’s building codes in 1892, which eliminated the requirement that masonry be used for fireproofing considerations. This opened the way for steel skeleton construction. Since it employed a steel skeleton with the steel coming from the American Bridge Company in Pennsylvania it could be built to 22 stories (285 feet) relatively easily, which would have been difficult using other construction methods of that time. It was a technique familiar to the Fuller Company, a contracting firm with considerable expertise in building such tall structures. At the vertex, the triangular tower is only 6.5 feet (2 m) wide; viewed from above, this pointed end of the structure describes an acute angle of about 25 degrees.
