Cast stone, as we know it today, dates back to ancient Rome with the invention in the second century BC, of pozzolana cement and structural concrete – in fact, cast stone is a special form of high quality concrete.
Suitable for structural applications, the material was used in Rome, as an alternative to natural stone, to form wide vaulted arches and gateways at the Colosseum and for the Pantheon's famous 50m span dome.
Development of artificial stone
The first recognised examples of cast stone being used in a position where it was intended to be seen were in medieval France. Lintels resembling natural stone were cast from natural aggregates and lime-pozzolan cement and used in the repair of the walls of the fortified city of Carcassonne, France around 1135.
The rediscovery of concrete in the 19th century and the invention of Portland cement – which resembled Portland limestone in colour – led to a large number of patented 'artificial' stones. Joseph Aspdin, a Leeds bricklayer took out a patent for his Portland cement in 1824 though he claimed he had been making it since 1811. By 1863, Portland cement was deemed to be ‘quite common cast in ornaments’.
As early as 1770, Daniel Pincot identified the refusal of some to accept that an artificial stone can be superior to its natural equivalent; ‘there are some persons so obstinately averse to the introduction of whatever they imagine has but the air of novelty, that they will be both blind and deaf to the plainest demonstration.’ He found this incredibly frustrating as he believed that ‘ artificial stone …. though the outward appearance is nearly the same, the internal properties are totally different, and far superior to all the common sorts of rock stone.’
Simulated stone in Britain
The earliest reference to artificial stone uncovered in England relates to Sutton Place in Surrey, where Henry VIII’s (1491-1547) brewer is recorded as having used ‘artificial stone or brick’ extensively.
Although by no means the first manufacturer, the first architecturally significant use of simulated stone in Britain was Coade Stone (1769-1821), which was used extensively for classical detailing by architects of the time, including Robert Adam, John Nash and Sir John Soane.
One notable example of the use of Coade Stone was by Robert Adam in the Syon Park gateway (see Syon Park Gateway and Porters' Lodge images left).
The first recorded commercial production of a cement based cast stone material in the format we know today, was in the late 1820s when Felix Austin went into business making artificial stone in New Road (now Euston Road), London, England. His material was not the same as the ceramic body used by Mrs. Coade, (although he is known to have copied old Coade designs), but made from Portland cement, broken natural stone, pounded marble and coarse sand.
Around 1840 Austin entered into partnership with John Seeley. Seeley had trained at the Royal Academy Schools and also made an artificial stone, which he called ' artificial limestone ', before entering into partnership with Austin. In 1841 Austin and Seeley published their first catalogue, Collection of Ornaments at Austin & Seeley's Artificial Stone Works for Gardens, Parks and Pleasure Grounds. The firm continued in production until about 1872.
Although their cast stone products were rarely stamped with the makers mark, items by Austin and Seeley can often be identified by their quality, which was recognised by Queen Victoria, who can be included among their patrons. Their urns and statues remain in great demand and currently achieve prices of many thousands of pounds at auction.
As the twentieth century dawned and cement based manufacture became more widespread, William Diack in 1904, in The Stone Trades Journal, commended cast stone as a substitute for natural stone in all areas.
Martin Earle’s stand at the Building Trades Exhibition at Olympia 1910 featured cast stone balustrading and urns, which were exported all over the world.
The revival of neoclassical forms in the 20th century aided the use of reconstructed stone to emulate natural Portland stone facades.
The Architects’ Journal, in 1932, when comparing Bath natural stone to its artificial equivalent, identified that ‘the reconstructed material is … much more durable, and has no natural bed, so there can be no flaking of the surface. It is unaffected by sea air, and the face is not destroyed by sulphurous atmosphere.’
The first British Standard for Cast Stone was BS 1217, which having been approved by the Cement, Lime & Gypsum Industry Committee was published on 6th April 1945. Subsequent revisions to BS 1217 were produced in conjunction with the UK Cast Stone Association in 1975, 1986 and 1997, with the current version being produced in 2008.
Cast stone today
By the late 1980s, perceptions were changing once again: ‘ cast stone has come a long way since then and some feel that the best look so like the real thing that they could threaten the future of the stone industry.’ ‘ Cast stone may, when properly designed, manufactured and installed, be as durable as many natural stones.’ For this reason, by 1989, The Journal of Preservation Technology was describing cast stone material as being ‘fully accepted’.
Cast stone was increasingly used for structural applications and larger panels with complex reinforcements. And post modernist architects use classical cast stone detailing to relate to an existing context such as brickwork with string courses, pediments, gables and cornices. The material is widely used by house builders to add value to their schemes.
In the 1990s much research relating to artificial stone was undertaken by the University of Dundee, the potential importance of this being recognised by Building Design in 1990: ‘The Dundee programme may well lead to concrete as architectural cast stone being reinstated as a high quality 21st century building material.’ The Dundee programme culminated in a joint research programme by the University of Dundee and the UK Cast Stone Association (UKCSA), making a number of interesting conclusions relating to artificial stone when compared to natural stone, in effect stating that both materials are generally comparable: ‘ All Cast Stone products, and particularly when waterproofed, were found to be highly resistant to carbonation. Efflorescence did not occur in any of the test samples and weathering in Cast Stone was similar to that in control natural stone. The data also suggests that dry-cast, Cast Stone is no less vulnerable to frost attack than natural stone.’
‘Unfortunately for contemporary advocates of artificial stone, whilst poor artificial stone is rightly vilified, good artificial stone so quickly takes on the appearance of natural stone that it is often mistaken for, and assumed to be, natural stone and so is not given the acclaim it deserves.’
‘Through technological advances and rigorous testing regimes, the quality of cast stone from a United Kingdom Cast Stone Association member is undoubtedly higher and more consistent than has been created at any time in the history of artificial stone. One can only wonder how historians will review the works of present day manufacturers in the centuries to come, for it would appear that it is only with hindsight that we are prepared to properly judge this material.’
Extracts from ' Artificial Stone. A successful substitute for natural stone? ' used by kind permission of the author, Simon Scott.
 'The History of Blue Circle', 1988
 Robert Kerr, ‘ On Artificial Stone ’ RIBA Transactions 1862-63, London 1863, P145
 Daniel Pincot, ' Artificial Stone ', London 1770, p11
 Daniel Pincot, ' Artificial Stone ', London 1770, p35
 John Cladius Loudon, ' Encyclopaedia of Cottage, Farm and Villa Architecture and Furniture ', London 1846, P142
 ' The Builder ', 1868
 William Diack, 'The Art of Masonry in Britain', The Stone Trades Journal, 1904
 F.R.S Yorke, ‘ Concrete and Artificial Stone ’, Architects Journal, 1 June 1932 p729
 Charles Wagner and Ian McCaig, ‘ Cast Stone ’, Traditional Homes, October 1987, p10
 Charles Wagner and Ian McCaig, ‘ Cast Stone ’, Traditional Homes, October 1987, p12
 ' The Journal of Preservation Technology ', Vol XX1, Nos. 3 / 4 1989
 Richard Carr, ‘ Set in their Ways ’, Building Design, 26 October 1990, p33
 ' Research Study into the Development of a Standard Test method and Performance Specification for Cast Stone ', University of Dundee
 Simon Scott, ' Artificial Stone. A successful substitute for natural stone? ', 2009, p100
 Simon Scott, ' Artificial Stone. A successful substitute for natural stone? ', 2009, p103