A STONE GLOSSARY
MAY 2018
William ‘Strata’ Smith’s 1815 Geological Map, the first nationwide geological map ever published.
We are in the process of choosing the stone to be used for a new building in Cambridge. It has been an apparently exhaustive journey through marbles and limestones from the UK, Europe and beyond. We amass endless samples, and talk in detail to quarrymen, masons and engineers about bed heights, weathering, and reliability of supply, as well as the inevitable costs to quarry the stone, cut it to shape, and fix it together to form a building. One of the most fascinating elements of this process are the specialist terms used to describe building stones and their properties. Below is a list of a few favourite words, ordered to explain the material properties that have so far governed our explorations for this new project.
The Clipsham Quarry at Rutland in Lincolnshire. Clipsham Stone occurs in the Inferior Oolite of the Jurassic System, where it was laid down between 174 and 163 million years ago. Clipsham is a popular building limestone with a characteristic golden colour. We have recently worked with it at Bishop Edward King Chapel in Cuddesdon and the Sultan Nazrin Shah Centre in Oxford.
Bedding plane
Many building stones, including all limestones, are sedimentary rocks, formed by the gradual settlement and compression of underwater sediment over millions of years. The directional way in which they were formed governs their properties and how they can be used as building stones. Most UK limestones must be used ‘naturally bedded’, i.e. orientated in the building in the same way that they were formed in the ground. This means the height of the blocks is limited to the depth of the bed, rarely more than 1m in the UK. ‘Face-bedding’, when blocks are laid so their bedding planes are parallel with the vertical face of the block, can lead to rapid weathering and crumbling.
Metamorphic
A stone that began as another type of rock and changed as a result of exposure to heat and pressure over geological time. Marble was originally limestone, and is chemically identical to it. However, the metamorphic processes changed its physical properties so that it does not have bedding planes, and can be cut and orientated in any direction. This makes it ideal if tall blocks are required.
Precipitation
The chemical process by which Travertine is formed, usually when geothermally heated water is exposed to the air, causing it to degas and carbonate minerals to precipitate out from the water. Although a type of limestone, its distinctive formation means it also doesn’t have bedding planes and is workable in much longer, thinner pieces than sedimentary stones.
Oolitic
A type of limestone made from an amalgamation of individual grains called ooliths. An oolith is a tiny carbonate particle surrounded by concentric layers of calcium carbonate, which were deposited as the ooliths were rolled around on the bed of the clear shallow sea in which the stone was formed. This gives the stone an even structure so it can be cut or sculpted in any direction, a characteristic which makes oolitic stones ‘freestones’. Portland Stone is an oolitic limestone used extensively in London’s historic buildings, perhaps most famously in churches by Cristopher Wren and Nicholas Hawksmoor, including St Paul’s Cathedral and Christ Church Spitalfields.
CLAD IN A GARMENT OF POETIC IMAGERY
JANUARY 2014
The following text seeks to explore the communicative role of architecture, highlighting how the buildings of Louis Sullivan offer an antidote to the stoicism of the modern movement.
The reasons for the adoption of a muted architectural language in the beginning of the 20th century were numerous, but perhaps the inability of architecture to communicate can be traced back to a Critique of Judgement wherein Immanuel Kant called for true artists to ignore conventional rules governing popular taste as a means to preserve the integrity of the artist / genius in the landscape of an emerging aesthetically uneducated middle class. The restriction of this Kantian ideology can be clearly seen in the modern movement where the elimination of ornament in favour of purely functional structures was meant to appeal to our morality. We were meant to appreciate their honest expression but this simplified architectural rhetoric stripped architecture of its ability to express meaning beyond its function and reduced the ability of the architect to infer a narrative.
It is here I believe that the architecture of Louis Sullivan offers a counterpoint to the stoicism of the modern movement. Sullivan’s response to the modernist doctrine was not to abandon ornament but to heed the advice of Owen Jones and devise a new and contemporary ornamental vocabulary. The Guaranty Building represents the high point of Sullivan’s communicative architecture. The building presents a veiled ornamental screen of rich terracotta tiles which act to delineate the tripartite composition of the facades. The ornament at the base of the building reflects the connections of its veiled steel structure which support the vertical mullions above. The repetitive program on the upper floors are articulated by a rigid pattern of piers and ornate spandrels. Sullivan completes the composition by employing a concave cornice which absorbs the vertical mullions and acts to complete a flowing continuous organic architecture.
‘Our buildings thus clad in a garment of poetic imagery… will appeal with redoubled power, like a sonorous melody overlaid with harmonious voices’[1] . Although Sullivan never acknowledged the influence of Semper, the Garment analogy used by Sullivan is a clear reference to Semper’s theory of dressing and his insistence that the ‘archetypal origin of built form was textile production’[2]. It is also indicative of the ‘strong influence that German culture had on Chicago in the 19th century’[3].
Ornament was for Sullivan and Semper a demonstration of essential artistic and social motives, ‘being fundamental, the wreath was not only initial, it was also profoundly significant because it manifested the unity of the social body, the people themselves’ [4.
Sullivan’s Architecture represents an alternative modernism where function and ornament were not considered to be in opposition but could coexist to create a symbolic architecture which sought to communicate.
[1] Louis H Sullivan, Kindergarten Chats, Dover Publications Inc, 1980
[2] Kenneth Frampton, Studies in Tectonic Culture, The MIT Press, 1995
[3] Ibid.
[4] David Leatherbarrow, The Roots of Architectural Invention, Cambridge University Press, 1993
Images from John Szarkowski – ‘the idea of Louis Sullivan’ Thames & Hudson, 2000
Joseph Mackey holds a BArch degree from University College Dublin. Joseph won an Architecture Association of Ireland Student Award in 2006 and the Arup Architecture Graduates Medal in 2010. Between 2006 and 2012 he worked with the Renzo Piano Building Workshop in Paris, Tom dePaor in Dublin and Eric Parry Architects in London. Since joining Niall McLaughlin Architects in 2012 he has been working on a chapel for monks in Dublin, the repair and extension of the old Radcliffe Infirmary Outpatients Building in Oxford and the T1 Building for Argent in King’s Cross, London. The T1 Building is a large mixed use development containing a district energy centre, an indoor sports pitch, car parking, shops, bars and 80 apartments.