What Is Cast-Iron Architecture?

What's the Difference Between Cast Iron and Wrought Iron?

Cast-Iron Facade Detail of the Haughwout Building in New York
Cast-Iron Facade Detail of the Haughwout Building in New York. Photo by Carol M. Highsmith/Buyenlarge/Archive Photos/Getty Images (cropped)

Cast-iron architecture was a popular type of building design used throughout the world in the mid-1800s. Its popularity was due, in part, to its timesavings and cost-effectiveness—a regal exterior facade could be mass-produced inexpensively with cast iron. Entire structures could be prefabricated and shipped around the world as "portable iron houses." Ornate facades could be "hung" on the new steel-framed tall buildings being built in the late 19th century.

Cast iron was used in both commercial buildings and private residences.

What Is the Difference Between Cast Iron and Wrought Iron?

Iron is a soft, natural element in our environment. Elements like carbon can be added to iron to create other compounds, including steel. The properties and uses of iron change as different element proportions are combined with various heat intensities—the two key components are mixture proportions and how hot you can get a furnace.

Wrought iron has a low carbon content, which makes it pliable when heated in a forge—it is easily "wrought" or worked on by a hammer to shape it. Wrought iron fencing was popular in the mid-1800s as it is today. The innovative Spanish architect Antoni Gaudí used decorative wrought iron in and on many of his buildings. A type of wrought iron called puddled iron was used to construct the Eiffel Tower.

Cast iron, on the other hand, has a higher carbon content, which allows it to liquify at high temperatures.

The liquid iron can be "cast" or poured into prefabricated molds. When the cast iron is cooled, it hardens. The mold is removed, and the cast iron has taken the shape of the mold. Molds can be reused, so cast-iron building modules can be mass produced, unlike hammered wrought iron. In the Victorian Era, highly elaborate cast-iron garden fountains became affordable for even a rural town's public space.

In the US, the fountain designed by Frederic Auguste Bartholdi may be the most famous—in Washington, DC it's known as Bartholdi's Fountain.

For more examples of how cast iron is used, see Cast-Iron Architecture, A Gallery of Images.

Why Was Cast Iron Used in Architecture?

Cast iron was used in both commercial buildings and private residences for many reasons:

  • Inexpensive means to reproduce ornate facades, such as Gothic, Classical, and Italianate
  • Grand architecture symbolic of prosperity became affordable
  • Thought to be a fireproof
  • Allowed a more open floor plan design, with space to accommodate larger windows suitable for commerce
  • Elaborate facades could be mass produced rapidly
  • Prefabrication enabled portability—entire buildings could be constructed in one place and shipped all over the world.
  • Cast iron molds could be reused, allowing for the development of architectural catalogs of module patterns that could be optioned to prospective clients
  • Easy repair of broken or weathered components, if the mold still existed

Who Is Known for Working in Cast Iron?

  • Abraham Darby (1678-1717), developed new furnaces in Britain's Severn Valley that allowed his grandson, Abraham Darby III, to build the first iron bridge in 1779
  • Sir William Fairbairn (1789-1874), Scotland, engineer, said to be the first to prefabricate a flour mill in iron and ship it to Turkey c. 1840
  • Sir Joseph Paxton (1803–1865), English landscaper, designed the Crystal Palace in cast iron, wrought iron, and glass for the Great World Exhibition of 1851
  • James Bogardus (1800-1874), New York City, self-described originator and patent-holder for cast-iron buildings, including 85 Leonard Street and 254 Canal Street in NYC
  • Daniel D. Badger (1806–1884), NYC, whose Architectural Iron Works is responsible for many portable iron buildings and lower Manhattan facades, including the E.V. Haughwout Building

What Others Say About Cast-Iron Architecture:

Everyone is not a fan of cast iron. Perhaps it's been overused, or it is emblematic of a mechanized culture. Here's what others have said:

"But I believe no cause to have been more active in the degradation of our natural feeling for beauty, than the constant use of cast iron ornaments....I feel very strongly that there is no hope of the progress of the arts of any nation which indulges in these vulgar and cheap substitutes for real decoration."John Ruskin, The Seven Lamps of Architecture, 1849, pp. 58–59
"The spread of prefabricated iron fronts imitating masonry buildings quickly aroused criticism in the architectural profession. Architectural journals condemned the practice, and various debates were held on the subject, including one sponsored by the recently founded American Institute of Architects."—Gale Harris, Landmarks Preservation Commission Report, p. 6, March 12, 1985 ( PDF).
"[The Haughwout Building,] a single pattern of classical elements, repeated over five floors, yields a facade of extraordinary richness and harmony...[The architect, J.P. Gaynor] invented nothing. It is all in how he put the pieces together...like a good plaid....A building lost is never regained."—Paul Goldberger, Why Architecture Matters, 2009, pp. 101, 102, 210.

Learn More:

  • The Maintenance and Repair of Architectural Cast Iron by John G. Waite, AIA, Preservation Brief 27, National Park Service, U.S. Department of the Interior
  • Cast-Iron Architecture in America: The Significance of James Bogardus by Carol Gayle, 1998
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  • Cast Iron and the Crescent City by Ann Masson and Lydia Schmalz, 2011
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  • Badger's Illustrated Catalogue of Cast-Iron Architecture, 1865, Dover Publications, 1982
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    Public Domain version online at the Internet Library
  • Cast-Iron Architecture in New York: A Photographic Survey by Margot Gayle and Edmund V. Gillon (1974)
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