The continuous improvement in the processing of iron and concrete during the Industrial Revolution opened up new and previously undreamt-of potentials for architects and engineers. At the same time industrialisation caused a revolution in the construction of housing as a result of the grave deficit in decent housing caused by the thousands of workers who migrated to booming factory regions.
One of the first entrepreneurs to concern himself with social questions was the early British socialist, Robert Owen. At the end of the 18th century he conceived an ideal town for his workers in the utopian tradition of the Renaissance. The idea, however, was never implemented. A textile manufacturer by the name of Titus Salt was much more successful in this respect. In 1851 he built an estate of terraced houses called "Saltaire" for his workers in West Yorkshire.
In France Charles Fourier developed similar ideas for cooperative production and housing. Following his example, in 1859, Jean-Baptiste Godin set up a housing estate next to his foundry in Guise, called "Familistère". This consisted of housing blocks several storeys high, each surrounding a large courtyard covered with a transparent glass roof and serving as a common space for all the inhabitants. Public facilities like schools, kindergartens and shops were integrated into the site.
The British town planner, Ebenezer Howard, responded to the uncontrolled growth of cities with the idea of the garden city. Influenced by the thoughts of the American writer Ralph Waldo Emerson, he propagated the philosophy of small towns integrated into the countryside, and consisting of single-family houses and community facilities. The land itself was to be owned in common. The concept was made reality in 1903 in the garden city of Letchworth in Hertfordshire. This was soon followed by another garden city in Hampstead, north London.
Architectural potentials increased with the use of iron, whose quality continuously improved during the Industrial Revolution. Using iron and glass it was possible to construct buildings like the translucent Palm House in Kew Gardens (1848) and the even more famous "Crystal Palace" built by Joseph Paxton in 1851. Paxton used prefabricated panes of glass with iron or wooden structural supports: a forerunner of the standard industrial buildings in the 20th century.
A second new material used by architects from 1867 onwards was reinforced concrete, a compound material first developed by a French gardener called Joseph Monier for garden tubs. Thanks to steel reinforcement bars or fibres integrated into the concrete to take up the stress and resist compression, it became possible to construct gigantic cantilever domes from the resulting compound. The start of the 20th century saw a steady increase in the amount of factory buildings, bridges and houses built of reinforced concrete.
Around this time the contrast between engineers and architects – between functional building and building art - came to a head. During the 19th century the profession of "civil engineer" had developed in Great Britain. This was a person who was not only versed in engineering above and below the ground, but also in factory engineering equipment. One of its most prominent representatives was Sidney Stott, who began his career by building multi-storey spinning mills in the Manchester region, and was later responsible for building textile factories in the border region around north-west Germany and the Netherlands.
As a reaction to this, more traditional architects preferred to refer back to the craft qualities and building arts of the mediaeval age. At the end of the 19th century the arts and craft movement exerted considerable influence in Great Britain; and in France, Eugène-Emmanuel Viollet-Le-Duc analysed Gothic construction principles. "Jugendstil" flourished above all in Germany and Austria – even in industrial buildings like the engine house in the Zollern colliery in Dortmund.
At the start of the 20th century a group of committed architects got together in Germany with a common idea of combining artistic design with modern materials and functional construction. The pioneer was a man named Peter Behrens, who served on the artistic advisory committee of the gigantic AEG power company from 1907 onwards. In Berlin he constructed a turbine factory from concrete, steel and glass. Functionally it was a long open production building with windows stretching to the roof; and yet it was designed with a feeling for tradition, with massive corners and powerful pillars.
His colleague, Walter Gropius, further developed this concept in 1911 in the form of the "Fagus works", a shoe last factory in Alfeld. He designed the complete facade with glass windows filled with thin iron frames supported by narrow brick mullions. In this way he was able to give the building an impression of transparency and lightness. The corners of the administration building have since become an icon in modern architecture: they consist completely of glass windows without corner pillars, because Gropius shifted the structural supports to the inside of the house. Using this as a starting point he was able to develop an uninterrupted expanse of clear glass known as the "curtain wall", one of the most influential forms of architecture in the 20th century.
The most radical solution in industrial building was invented in the USA. In 1908 Albert Kahn built a factory near Detroit for the Ford motor works which was absolutely suitable for conveyor-belt work: a long hall at ground level, in which all manufacturing steps could be conducted in sequence, and cars could be put together from pre-pressed pressed steel parts in a short amount of time. The building could be extended with new modules when required.
After the First World War the lack of places to live was so great that governments and corporative companies were compelled to invest huge amounts of money in housing construction. In Great Britain large estates of single-family houses were built; and in Germany blocks of flats where erected, preferably in long parallel lines placed in such a way as to allow sufficient daylight to reach each row. The blocks of flats often contained children's crèches, shops and laundries.
Cooperative philosophies were especially expressed in the housing blocks built in Vienna in the 1920s. The best known of these was the "Karl-Marx-Hof", a monumental "proletarian housing palace" consisting of five-storey houses, each of which surrounded a broad grassy courtyard. Shops and kindergartens, even libraries and post offices were also integrated into these fortress-like housing blocks in "Red Vienna". The Dutch constructed expressive housing blocks. At the start they were often made from traditional red bricks and occasionally crowned with a little tower: later ready-made concrete bricks with individually accented coloured facades were also used, as in the "Watergraafsmeer" garden city near Amsterdam.
By contrast, the housing estates erected by representatives of functional architecture contained cube-shaped houses with flat roofs and white rendering. Standardisation went so far that progressive aspects like facing the housing towards the sun or grassing over courtyards became background considerations once again, even in the housing estates designed by Gropius. In addition, Gropius, who still clung on to the ideal of cooperative housing, committed himself strongly to the building of tower blocks. This trend reached a climax in the work of the architect and artist Le Corbusier. His idea of a housing city was finally implemented in 1955 in the form of the "Unités d’Habitation" in Marseilles. This was a massive concrete edifice containing more than 300 housing units, connected by a network of "streets" and containing two floors of shops. Although it soon became clear that there were blatant deficiencies in the architecture, the site had a huge influence on housing construction.