Chicago’s architecture is famous throughout the world and one style is referred to as the Chicago School. Much of its early work is also known as Commercial style. In the history of architecture, the first Chicago School was a school of architects active in Chicago at the turn of the 20th century. They were among the first to promote the new technologies of steel-frame construction in commercial buildings, and developed a spatial aesthetic which co-evolved with, and then came to influence, parallel developments in European Modernism. A “Second Chicago School” later emerged in the 1940s and 1970s which pioneered new building technologies and structural systems such as the tube-frame structure.

First Chicago School
While the term “Chicago School” is widely used to describe buildings constructed in the city during the 1880s and 1890s, this term has been disputed by scholars, in particular in reaction to Carl Condit’s 1952 book The Chicago School of Architecture. Historians such as H. Allen Brooks, Winston Weisman and Daniel Bluestone have pointed out that the phrase suggests a unified set of aesthetic or conceptual precepts, when, in fact, Chicago buildings of the era displayed a wide variety of styles and techniques. Contemporary publications used the phrase “Commercial Style” to describe the innovative tall buildings of the era rather than proposing any sort of unified “school”.

Some of the distinguishing features of the Chicago School are the use of steel-frame buildings with masonry cladding (usually terra cotta), allowing large plate-glass window areas and limiting the amount of exterior ornamentation. Sometimes elements of neoclassical architecture are used in Chicago School skyscrapers. Many Chicago School skyscrapers contain the three parts of a classical column. The lowest floors functions as the base, the middle stories, usually with little ornamental detail, act as the shaft of the column, and the last floor or two, often capped with a cornice and often with more ornamental detail, represent the capital.

he “Chicago window” originated in this school. It is a three-part window consisting of a large fixed center panel flanked by two smaller double-hung sash windows. The arrangement of windows on the facade typically creates a grid pattern, with some projecting out from the facade forming bay windows. The Chicago window combined the functions of light-gathering and natural ventilation; a single central pane was usually fixed, while the two surrounding panes were operable. These windows were often deployed in bays, known as oriel windows, that projected out over the street.

Architects whose names are associated with the Chicago School include Henry Hobson Richardson, Dankmar Adler, Daniel Burnham, William Holabird, William LeBaron Jenney, Martin Roche, John Root, Solon S. Beman, and Louis Sullivan. Frank Lloyd Wright started in the firm of Adler and Sullivan but created his own Prairie Style of architecture.

The Home Insurance Building, which some regarded as the first skyscraper in the world, was built in Chicago in 1885 and was demolished in 1931. Some of the more famous Chicago School buildings include:

Louis Sullivan’s Carson, Pirie, Scott & Co. Building
Auditorium Building
Gage Group Buildings
Heyworth Building
Leiter I Building
Leiter II Building.jpg Leiter II Building
Monadnock Building
Montauk Building
Rookery Building

Buildings outside Chicago
Buildings outside Chicago include:
Prudential (Guaranty) Building, 1896, Buffalo, New York
Union Bank Building, 1904, Winnipeg, Manitoba, Canada
ManchesterCourts1 annzstream.jpg Manchester Courts, 1906, Christchurch, New Zealand (demolished 2011)
Blount Building, 1907, Pensacola, Florida
OldNationalBank.jpg Old National Bank Building, 1910, Spokane, Washington
ConsultancyHouse.jpg Consultancy House, 1910, Dunedin, New Zealand
StJames-Building-Jacksonville-2006.jpg St. James Building, 1912, Jacksonville, Florida
Western Auto.jpg Western Auto Building, 1914, Kansas City, Missouri
Nicholas Building, 1926, Melbourne, Australia

Second Chicago School
In the 1940s, a “Second Chicago School” emerged from the work of Ludwig Mies van der Rohe and his efforts of education at the Illinois Institute of Technology in Chicago. Its first and purest expression was the 860–880 Lake Shore Drive Apartments (1951) and their technological achievements. This was supported and enlarged in the 1960s due to the ideas of structural engineer Fazlur Khan. He introduced a new structural system of framed tubes in skyscraper design and construction. The Bangladeshi engineer Fazlur Khan defined the framed tube structure as “a three dimensional space structure composed of three, four, or possibly more frames, braced frames, or shear walls, joined at or near their edges to form a vertical tube-like structural system capable of resisting lateral forces in any direction by cantilevering from the foundation.” Closely spaced interconnected exterior columns form the tube. Horizontal loads, for example wind, are supported by the structure as a whole. About half the exterior surface is available for windows. Framed tubes allow fewer interior columns, and so create more usable floor space. Where larger openings like garage doors are required, the tube frame must be interrupted, with transfer girders used to maintain structural integrity.

The first building to apply the tube-frame construction was the DeWitt-Chestnut Apartment Building which Khan designed and was completed in Chicago by 1963. This laid the foundations for the tube structures of many other later skyscrapers, including his own John Hancock Center and Willis Tower, and can be seen in the construction of the World Trade Center, Petronas Towers, Jin Mao Building, and most other supertall skyscrapers since the 1960s.

Today, there are different styles of architecture all throughout the city, such as the Chicago School, neo-classical, art deco, modern, and postmodern.

Architects of the Chicago School
William Le Baron Jenney (1832 – 1907). The father of the school of Chicago projected the Home Insurance Building in 1884, being considered the first building built with iron skeleton, although some of its walls had supporting function. It also opens the aesthetic doubts to accommodate the office floors in a typology like this, which was unprecedented. There was the need to concentrate more people in less space and this building emerged, which became the first with 10 floors. With the technique of iron linkers based on pillars, beams and trusses covered with a protective substance against fire, high-rise buildings will be achieved without the need for very thick pillars, allowing the system to eliminate almost completely the wall. Thus, numerous windows are established between the pillars, the bow-windows 7 with three windows, allowing ventilation of the wide interiors and the necessary lighting. Also called Chicago windows , in which the bay is divided into three parts, with a large fixed central panel and the sides divided into two movable panels ( sash windows ). 8
Henry Hobson Richardson (1838 – 1886). His Marshall Field’s Wholesale Store , 9 1887, is not a building that has too many floors but is already beginning to stand out among the others. The exterior of the building is very simple (a free interpretation of the European Romanesque is made). The walls are consistent, unpolished stone (building tradition of Massachusetts), but the openings (windows) are fulfilling the function of capturing light. We can highlight the use of different shapes and sizes. The resounding structure, in its solid and unitary character, makes it stand out and affirm its individuality in the urban chaos that welcomes it.
Burnham & Root . In the study of Le Baron Jenney two characters were met that synthesize the two components of the American professional reality. Daniel Burnham was practical, enterprising, with great capacity for public relations, was the promoter, realistic and cynical, while John Wellborn Root 10 was more artistic, with a more cultivated talent. Together they built buildings such as the Montauk Building , 1882-1883, the Rookery Building 1885-1887, the Reliance Building , 1890, the Masonic Temple Building , 1891-1892, or the start of the Monadnock Building , among others.
Holabird & Roche . They built, among other buildings: Graceland Cemetery Chapel , 1888, the continuation of the Monadnock Building , 1893, McConnell Apartments , 1897, Gage Group Buildings , 1899, Chicago Building , 1904. The firm began with William Holabird and Ossian Cole Simonds in 1880. Simonds was replaced by Martin Roche in 1883. In 1927, Holabird’s son, John Augur Holabird , associated the company with John Wellborn Root, Jr. (the son of John Wellborn Root), who worked at the firm since 1914. In the following years evolved towards the Art Deco style.
Dankmar Adler (1844 – 1900). He built the Auditorium Building , 1887-1889.
Louis Sullivan (1856 – 1924). His most important contribution was the design of different types of skyscrapers, with the interior iron structure under an attractive masonry façade. The Wainwright Building , the Guaranty Building and the Carson Pirie Scott Department Store (Carson Stores) are buildings that bear your signature.

Constructions outside of Chicago
The influence of the Chicago school, and the work of the architects trained in it, soon spread to other cities in the United States, Canada and even as far away as New Zealand.

Some architectural movements of the time share some traits with it, such as the Glasgow School of Architecture ( Charles Rennie Mackintosh ).

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