Architectural ceramics

Materials World magazine
,
3 Nov 2013
Spanish Pavilion, Expo 2005 – Japan Foreign Office Architects

The use of ceramics in architecture has seen a recent global resurgence. Alexis Harrison, Senior Designer at Arup Materials in London, UK, reveals some innovative uses of this traditional building material.

Architectural ceramics are again becoming a key material in building façade design. One of the oldest and most familiar materials known to man, clay brick is being used in new and exciting ways. But other, less familiar, clay materials such as architectural terracotta and faience (glazed terracotta) are finding their way to the forefront of architectural design.

The technology of architectural ceramics has changed little from the complex geometric Moorish tiles of Spain’s Alhambra in Granada or the 19th Century terracotta and faience cladding on some of our greatest municipal buildings, such as Alfred Waterhouse’s Natural History Museum in London, UK. All incorporate a clay-based ceramic body, with or without an applied glaze. Today’s architects have begun applying new forms and finishes to these traditional materials. Historic producers such as Shaws of Darwen, based in Lancashire, UK, which has been around since 1897, have never been so busy, creating bespoke pieces for contemporary buildings.

Contemporary architectural ceramics can be produced using several methods, but are typically extruded (producing very regular, long, profiled terracotta planks and tubes) or slip cast in plaster moulds (producing more irregular, three-dimensional forms). Both types are attached to the primary structure of buildings in a number of ways, and the engineering behind the hidden fixing solutions are often as innovative as the cladding material itself.

Quadrant 3, London
Dixon Jones and Arup

Quadrant 3 is a mixed-use development near Piccadilly Circus on the site of an Edwardian Hotel. Corner elements of the white faience, steel-framed hotel were retained as bookends, and three new façades were inserted between them featuring white, green and blue faience tiles composed around bronze-edged glazing. Despite the higher cost, handmade slip-cast faience was chosen over extruded glazed terracotta for its varied and irregular surface quality.

Arup developed a precast concrete solution for the ceramic cladding, whereby 40mm-thick faience tiles are factory-set into a reinforced concrete backing structure. The tiles are cast into the concrete via stainless steel pins, each isolated with a debonding layer to prevent differential thermal movement of the concrete causing the tiles to crack.

One Eagle Place, Piccadilly, London
Eric Parry Architects and Arup

This new development for the Crown Estate occupies a large block at the edge of London’s historic St James’s area. A new structure is fronted by a combination of retained, rebuilt and new Portland Stone façades, as well as an innovative faience façade fronting Piccadilly that re-establishes the classical order originally intended for the site.

The white faience pieces include complex 3D shapes to achieve the deep reveals that give the façade its sense of solidity. Double-height windows feature a striking rouge blush, created using ceramic transfers screen-printed from the architect’s digital origination and applied to the white faience units before a second firing.

Ceramic transfers have been widely used since they were developed in the mid-18th Century to accelerate the manufacture of decorated tableware, but this project represents their first significant use for architectural ceramics in the UK, with wide possibilities for the future.

Arup designed the structure for the faience cladding, supporting the pieces on vertical stainless steel cladding rails, with each piece pinned in four places. The rails span up to two storeys high and are supported at their base, allowing the brittle faience and their hydraulic lime mortar joints to move independently of the primary structure in the event of wind-induced building sway.

The crowning glory of the façade is the complex geometric cornice, designed by Turner Prize-winning artist Richard Deacon. The cornice realigns the façade with adjacent buildings, replacing the disjointed ones that previously stood on the plot. Again, transfers were employed to create the abundant multi-coloured glazes screen-printed from Deacon’s watercolour originals. The patterns recall the ever-changing digital billboards of Piccadilly, permanently fused in vibrant, colourfast glaze.

Central Saint Giles, London
Renzo Piano Building Workshop

Architect Renzo Piano is no stranger to using extruded terracotta cladding. His extension to IRCAM in Paris, France, in the late 1980s reinvented terracotta, before his buildings at Potsdamer Platz in Berlin placed the material firmly on the architectural map. Central Saint Giles replaces a grim concrete Government building on a busy traffic interchange in the heart of London’s West End with a series of brightly coloured, multistorey façades formed from a combination of glazed, extruded ceramic planks in a variety of profiles and extruded tubes known as baguettes.

The ceramic units were prefixed to 1.5-metre-wide by storey-height unitised aluminium curtain wall panels, enabling a complete weathertight façade to be installed within weeks. Ordinarily, ceramic cladding units are attached to the façade by hand once the main structure is weathertight, due to the high risk of breakage while installing larger units. However, Central Saint Giles was successfully installed with minimal breakages.

The vibrant glazed colours of the development are considered too much for some people’s view of London’s monotone pallet (one taxi driver suggested it was built from Lego) and extreme reactions either way have led it to become privately known as The Marmite Building. Nonetheless, it stands as a striking example of the beauty of ceramic glazes.

Villa Nurbs, Empuriabrava, Spain
Cloud 9

Villa Nurbs exemplifies a truly innovative approach to architectural ceramics. NURBS, or non-uniform rational B-spline, is a technical name for a complex curve in computer modelling.

The three dimensional, doubly curved ceramic tongues are formed by extruding wide ribbons of clay before cookie cutting out the individual tile shapes. The extruded shapes are stiff enough to be handled and are transferred onto CNC machined polystyrene forms, creating the doubly curved forms. Glazes are then hand applied before the pieces are transferred to the kiln. The completed units are hung onto a tensioned cable net to form the façade cladding.

Spanish Pavilion, Expo 2005 – Japan
Foreign Office Architects

Like Villa Nurbs, the ram-pressed ceramic pieces for this project were produced by Ceràmica Cumella, near Barcelona. Cumella is as much a ceramics studio as it is a factory, and specialises in the challenging and unusual, having undertaken art installations and restoration work on Gaudi’s iconic buildings. The Spanish Pavilion was conceived to marry the combined European and Islamic ceramic heritage of Spain with that of the Far East.

The individual glazed pieces were assembled back-to-back with metal fixings, and individually reinforced by a supporting post between each column of pieces.

Further information

Email Alexis Harrison alexis.harrison@arup.com