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Book reviews — June 2014

'Early Structural Steel in London Buildings: A discreet revolution', by Jonathan Clarke
English Heritage, Swindon, 2014, xiv + 393 pages, 357 illustrations, ISBN 978-1-84802-103-7, £75.00 (but see below for special offer to GLIAS members)
This is a valuable book, dealing with the early use of the only ferrous metal employed in construction today. Building in steel is a subject which, certainly in the UK, has received comparatively limited attention from both industrial archaeologists and architectural historians. This is perhaps understandable: it was with steel's predecessors, cast iron and wrought iron, that the UK pioneered the industrial expansion of the late 18th and 19th centuries, and so it tends to be iron structures that are best-known and highly regarded. (Think of the Iron Bridge at Coalbrookdale or the Crystal Palace in Hyde Park.) In the USA, on the other hand, major industrial and urban development came later, alongside the availability of cheap reliable steel, whose key role in construction history there has rightly been acknowledged through such notable building forms as the skyscraper and the long-span suspension bridge.

The sub-title reference to 'discreet' makes the point that one seldom sees 'naked' steelwork in most steel-framed buildings, but its presence very often helps to define their forms and appearance. So steel is important not merely as a material in the history of structures, but in the development of London as an industrial, commercial and social capital city. Steelwork is indeed usually concealed 'discreetly' within both the external façade, and internally, for several reasons. Unprotected steel corrodes in damp and aggressive atmospheres, and loses strength if exposed to fire — two practical reasons for encasing it. Moreover, its use in anything other than the most utilitarian building will call for some form of architectural treatment, which is likely to be influenced both by styles currently in vogue and by the surroundings. A prime example of this is Tower Bridge, whose stone cladding consciously respects the nearby Tower of London, but in reality is but a 'skin' over an early steel frame that provides both the bones and the muscle of this famous bridge. A more typical example appears in the first two illustrations in the book. The first shows the skeletal steel frame of Gloucester House rising on the north side of Piccadilly, while the second shows the building as it stands today, clad in white and pale green faience and with a huge semi-circular pediment above a two-storey attic. The steel frame is indeed 'discreet'. (Although Thomas Collcutt, its architect, might be taken aback to learn that its Edwardian splendour now houses the Hard Rock Cafe!)

Jonathan Clarke began studying the early use of steel in London while working in English Heritage in the late 1990s, and this book is the informative fruit of lengthy research. In eight introductory chapters he reviews the factors that led to the adoption of structural steel, and provides a useful overview of the making and structural uses of both iron and steel, before considering the application of steel to different building types in London.

Henry Bessemer in 1856 showed that steel could be made on a large and economical scale, using his 'converter' in which air was blown through molten pig iron to rapidly reduce its carbon content, producing a metal that was stronger than wrought iron and more ductile than the brittle cast iron of the day. (His research was undertaken at his laboratory in St Pancras, long since lost under the Midland Railway's footprint, so London has its place in the history of steel-making.) There were however problems in making sound steel from the common iron ores that were rich in phosphorus, while British ironmasters were intrinsically conservative and reluctant to invest in new plant. The Siemens-Martin open-hearth furnace developed in the mid-1860s made steel more slowly than the converter, which beneficially allowed better control over the product. Construction however took a back seat, as railway companies were eager to buy this new metal that was 'tougher' than wrought iron, hence much more resistant to the wear of rails by the pounding of steam locomotives, while shipbuilders could taken advantage of the greater strength of steel to reduce the weight of their hulls and so increase cargo capacity. So it was not really until the 1880s that steel began to be used in construction — a notable early example being the Forth Rail Bridge opened in 1890.

Steel could be made in bulk to a reliable consistency, unlike wrought iron which could only be made from molten pig iron in small quantities in a puddling furnace. Larger sections had to be formed by heating and forge-welding together these small pieces. All in all it was effectively an expensive, craft-based manual process with considerable variation in the product almost inevitable. Thus, although steel had similar (if superior) mechanical properties to those of wrought iron, the availability of cheap good-quality steel was revolutionary in its effects rather than evolutionary, and the use of structural wrought iron waned.

Commercial steel-making was already under way on the Continent, and long before today's open European market it was possible for the London engineer or builder to buy steel from France, Belgium, Germany and Luxembourg at a lower price than the products of Dorman Long and other British steel firms. This foreign competition spurred British firms to increase production and reduce costs.

London building regulations, always stringent since the Great Fire, were not conducive to the early adoption of steel framing. For example external walls had to be sized to carry their own weight and the loads from supported floors and roof, even when steel stanchions and beams which could carry these loads unaided had been put up along the wall lines to allow the speedy erection of the complete frame. This was not relaxed until the so-called 'Steel Frame' Act of 1909, which also prescribed loadings, allowable stresses, and other design considerations, and set the path for the rapid development of steel-framed construction in London. However, restrictions on building height meant that London did not follow the example of New York and Chicago, in particular, in becoming a city of skyscrapers — a restriction that applied until after World War II (and some might wish still applied!)

Architectural thinkers such as Ruskin and Morris were hostile to the use of iron and steel in buildings as they felt this would destroy the craftsmanship of the stonemason and other skilled trades. The construction of Tower Bridge was criticised for its 'fake' stonework, although others argued that efficient steel structure and decorative stone facings went together as do bones and muscle with skin.

The development of larger-scale steel construction accelerated the need for structural engineers who could advise architects and carry out competent design themselves, while it also brought forth capable steel fabricators and what would these days be called construction managers, headed by Americans with experience of fast and economical building in their own country. Alongside steel came the beginnings of reinforced concrete construction, initially to form the floors and other elements within a steel-framed building, but later to develop as a full-blooded competitor with steel for entire building structures.

These introductory chapters take up less than one-third of the book, but provide an essential understanding of the climate in which London began to build in steel. Five longer chapters then look at particular building types, and show how the adoption of steel expanded possibilities for their clients, their architects and their users. Each chapter includes a valuable review of forerunners to the use of steel.

The first such chapter deals with theatres and music halls. These public buildings were acknowledged as potential fire risks, while audiences often suffered restricted views of the stage, especially where vision was obstructed by columns supporting upper levels of seating. The use of large built-up steel girders, fabricated by riveting together plates and rolled sections, allowed clear spans across the auditorium, while secondary steel 'stringers' supported on back walls and these girders could cantilever forward to create spectacular balconies. The London Coliseum, among others, is well illustrated with fine colour photos showing what to me as a structural engineer is an almost hair-raising huge 'floating' balcony — truly a 'look, no hands' structure, very appropriate for a theatre, and showing that engineering a century ago could be as bold and imaginative as anything we can do today.

Chapters on clubs and hotels, and banks and offices, make clear that the ability of steel beams and girders to span long distances, requiring only a modest number of intermediate columns, was seized upon by architects to create imposing large spaces. The structure here again was often 'discreet', and entirely masked by applied decoration, but that was surely only logical for the uses to which these buildings were put.

Structures with a more or less utilitarian function are considered together in a chapter. For stores, such as Selfridges, the steel frame with widely spaced columns permitted large windows and display areas. Houses, private and philanthropic apartment blocks, churches, swimming pools, fire stations, and Underground stations all made use of steel. Churches and the like are good examples again of where a steel roof structure often sits discreetly above the ceiling, just as timber does in earlier structures. It also supports domes and other roof features, such as at Brompton Oratory and the Central Hall, Westminster. (If steel had been available to Wren, it is highly likely that he would have used it to support the dome of his St Paul's Cathedral!)

The fifth chapter in the study of building types addresses the wide range of industrial buildings for which steel — usually 'indiscreet', i.e. unclad — was ideal, such as factories, warehouses, workshops, and power stations.

The book's final chapter draws together the threads that have been laid out in substantial detail, and concludes that the adoption of steel led to innovations in the design of most types of building. The book clearly shows not only how steel evolved and was used as a structural material, but how its capabilities influenced architects who were designing a range of building types, allowing them to do things that had not been really achievable before, even using wrought and cast iron. These changes, and the way in which they took place, to my mind fully justify the sub-title of 'a discreet revolution'.

The book is, I'm pleased to say, printed in the UK, and is beautifully produced on art paper. There is an abundance of photographs and drawings, mostly in colour, that make browsing a pleasure but also complement the narrative. The very informative notes to the text, all 26 pages of them, are grouped at the back, which does make for a fair amount of leafing back and forth: my own preference would be footnotes to each page. The Bibliography runs to 12 pages, something like 600 sources, which would afford reading for a lifetime of study on this subject if one chose.

It is no exaggeration to say that this book is a ground-breaking study that encourages us to look at many London buildings in a different way. I think that it will appeal equally to those with a particular interest in construction history and archaeology, and those with a more general interest in London's buildings. Michael Bussell

Please note: English Heritage is generously offering to GLIAS members a 30% discount and free post and packing (UK only) on this book, if purchased direct from EH. To take advantage of this offer (rrp £75.00, discounted price £52.50), telephone 01235 465577 or email and quote reference number 7220140007. Offer expires 31.12.14.

© GLIAS, 2014