Over the past 100 years, the introduction of new materials such as plate glass and reinforced concrete has helped define modern design and given architects newfound freedom to explore structure and form. Throughout this period steel has, of course, played a major role as a structural support mechanism. Now – along with other metallics – it is being used as a coating for buildings, offering an intriguing, sculptural façade full of depth and textural possibilities.
This is especially true of weathering steel, most commonly known as Corten, which has become a favourite among architects and designers. When exposed to the elements, it begins to rust within a few weeks or months and continues to subtly evolve in colour and tone. In this way, it takes on a life of its own despite being manmade.
Corten was invented back in the 1930s by the US Steel Corporation and was initially put to industrial use, such as in railroad trucks. Over time, avant-garde sculptors became fascinated with the way it naturally weathers in the open air, forming a self‑protecting layer of rust. This engaging ruby‑coloured patina gives it an organic quality that contrasts with the heavy-duty strength of the steel itself, lending it a curious ambiguity.
Architects began to catch on to the rich opportunities offered by Corten in the 1970s and, slowly but surely, weathering steel started to be applied to statement buildings. Over the years, Corten classics have included Herzog & de Meuron’s CaixaForum cultural centre in Madrid and Thomas Heatherwick’s East Beach Café in Littlehampton, West Sussex. More recent gems include a striking visitors’ centre in Chile’s Atacama Desert, by architects Emilio Marín and Juan Carlos López, where a collection of Corten-clad pavilions in the open landscape assumes the look of an ambitious piece of land art.
Over the past decade, weathering steel has increasingly been used to craft some extraordinary new private homes that make the most of its ambiguous and intriguing character and its sculptural associations. Architect Sandy Rendel chose Corten to clad a new house alongside the River Ouse in Lewes, East Sussex. The building sits on the site of an old dockside workshop but the prominent setting at the edge of the town also has a striking natural backdrop of chalk cliffs, while the river itself forms a key part of the surroundings.
“We wanted to work with a robust, self-finished material to wrap the walls and roof that reflected the tones of the red clay bricks and tiles that you see in the area,” says Rendel. “The beauty of Corten is that the steel develops patina and character as it weathers. Instead of being at its best on day one and gradually wearing to a tired version of its original self, it changes and enhances its appearance as it stabilises, preventing further corrosion. It even self-heals and doesn’t need repairing.”
Home to Stephen and Anita Yeomans (an advertising executive and a lawyer) and their children, the house features a heavily glazed lower level that contrasts with the Corten-coated upper storey. “We love the colour and patina,” says Stephen, who has known East Sussex well since his late teens, when he used to live in nearby Brighton. “It alludes to the industrial heritage of the site, where they used to load chalk from the former Lewes quarry onto barges – but we also love how the house nestles sympathetically into the landscape. It strikes a perfect balance between being an audacious and contemporary building and fitting into the environment.”
American architect Tom Kundig became fascinated by the tectonic and sculptural aspects of Corten as a child. His family were good friends with artist Harold Balazs, and the young Kundig witnessed Balazs’s steel sculptures being made at his workshop in Washington state. In his own work for the practice Olson Kundig, he has repeatedly been drawn to weathering steel as a building material and used it extensively for a recent house called Studhorse in Winthrop, Washington, for clients Shane Atchison – the CEO of a digital agency – his wife Tasha and their two children. The family’s big passion is outdoor living, and their rural retreat in the Methow Valley forms an escape in a dramatic landscape. The house itself comprises a series of Corten and glass pavilions arranged around a courtyard, reminiscent of the idea of “circling the wagons”.
“Because I grew up around Corten and loved it, I already felt that it was an appropriate choice for a building,” says Kundig, who has used the material in a number of other projects apart from Studhorse. “As an architect there are a number of qualities that interest me: the way it ages and how it reacts to its surroundings and the weather patterns of its location, as well as the way it more or less takes care of itself. It is a beautiful material that resembles the natural colours of the landscape, like the bark of a ponderosa pine tree, the shade of sandstone or the tones of the earth.”
For both the architect and client the durability and lack of maintenance was a big factor in the choice of Corten, particularly in a remote setting such as the Methow Valley. Weathering steel looks after itself as long as a few basic rules are taken into account: the steel should not be in direct contact with the ground, and it is not suited to areas of high humidity or salt-laden coastal air that might lead to extreme rusting and corrosion. Otherwise, in most other environments the steel coat should be highly durable and long-lasting.
These were key factors for Australian architect Peter Stutchbury when he chose Corten for the Invisible House in the Blue Mountains of Australia. Here, too, the location is remote, with the property perched upon a hillside with open, panoramic views. Designed as a rural escape for a film director and artist, along with their young daughter, the lower storey – which holds the main living spaces – forms an open belvedere topped with two Corten pavilions on the upper level for the bedrooms. These seemingly floating steel structures echo the appearance of water tanks or agricultural sheds, lending the house a mysterious hybrid character.
“Corten appears to have a life of its own, and in that sense it is not a static material,” says Stutchbury. “Used correctly it requires no maintenance and it has this wonderful relationship with the mineral world, which gives it a timeless quality.”
For the clients, who were attracted to the setting by the open vista, the Invisible House is an elemental composition in an untamed landscape. “We loved the use of stone and concrete, and the Corten and steel roof is a very good complement to those materials,” they say. “The sculptural qualities of the house and how the light evolves through the day are a joy. Even when the wind is howling there is a sense of calm and reflection – it is a sanctuary.”
The organic patina of weathering steel makes it ideally suited to new country homes, yet it is also finding favour in much more urban settings. Richard Kim, who works as head of design for the Californian electric-vehicle company Faraday Future, was drawn to the material for the façade of his home in Silver Lake, Los Angeles, designed by Aaron Neubert Architects. Kim planned the building to replace a 1950s home and offer a studio to his partner, graphic designer Kristine Arellano, who collaborated with him in the design process. The Corten coat carries echoes of car design for Kim – who worked on BMW’s electric-car programme before joining Faraday – and has a solid, protective quality like the body of a motor vehicle. But there were other qualities that captivated him too.
“The Corten is the best part of the house,” says Kim. “It’s steel, of course, so extremely durable, and I will never have to do anything to maintain it. In some ways it’s industrial, but in many other ways it’s much more natural and cosy than typical home siding. It’s a lot like wood and tells a story as it ages, yet it’s better than wood in terms of maintenance. It took a year to fully develop its finish but will continue to change from reddish to dark purple over the next few years.”
In the Belgian city of Antwerp, architectural practice DMOA has used weathering steel in a rather different way within the design of its Corten House built for a family with three children. Instead of a flat façade, the steel has been used to create a series of lamellae – or vertical plates – that form a screen around the house. The plates make a striking and sculptural composition, even protecting some of the windows, and also create a latticed boundary around the garden, where they sit in vivid contrast to the greenery.
“Our clients were very much into industrial design, raw materials and earthy colours,” says principal architect Benjamin Denef. “But we were also searching for verticality in a somewhat boring Belgian street, where we designed this atypical little tower. To accentuate the form and make it look more elegant, the vertical lines were the best choice and we could use them to surround the garden, creating a kind of gallery. Corten does have plenty of assets to fall in love with – its structural strength, purity, unpredictable patina and the warm colour of the rust. And you can shape it in any way you can think of.”
Architects and home owners have also been exploring other kinds of metallic façades. The recent Royal Institute of British Architects longlist for the House of the Year included Tin House by Henning Stummel in London and Zinc House by LJR+H in Angus, Scotland. Also in Scotland, Alan Dickson and Gill Smith of Rural Design have just finished their own project, Tinhouse, on the Isle of Skye. Situated on a picture-perfect site overlooking the open water, the corrugated metal walls and roof are reminiscent of the tin sheds and barns common to the region.
“Those little tin sheds are very inspiring to us,” says Dickson. “They are ‘inbetween’ buildings that are inventive, creative and often quirky, although none of them is actually made of tin. Historically the corrugated metal used in those buildings was iron or galvanised steel, which can decay through rust, so we have used aluminium fixed to a timber frame. It will have a very long life and require very little maintenance, which gives it great appeal in our exposed climate.”
Dickson and Smith plan to let the Tinhouse to holiday guests. It is an ideal spot to enjoy both the landscape of Skye and the open view of the sea. There is something highly endearing about the simple form of the house and its corrugated skin, and it’s a great opportunity to test out living with metal cladding. Full metal jackets of all kinds are making their presence felt both in town and country in the most striking of ways.