Fishing floats, bottle stoppers, platform soles, pinboards, coasters. The uses of cork are many and varied, but it still retains a whiff of 1970s suburbia, like avocado bathroom suites or jumbo corduroy. Yet in its way, cork is a wonder material – strong in compression (those platform soles), water-resistant and a good source of insulation. Cork is also impeccably sustainable. Bark from Quercus suber, the cork oak, is carefully stripped by hand every nine to 12 years, leaving the tree intact, unlike felling for timber. Portugal and Spain are responsible for 80% of cork production, with much of it still going to make corks for wine bottles, despite the rise of the screw top.
As for cork in architecture – or “corkitecture” – the picture is more patchy. Cork has been a minor supporting player, used for flooring and wall tiles, or as an early form of insulation, sandwiched in walls. It has made the odd breakout appearance as cladding for temporary structures, such as Álvaro Siza and Eduardo Souto de Moura’s Portugal pavilion at Expo 2000 in Hanover, and the 2012 Serpentine Gallery pavilion by the Swiss partnership of Herzog & De Meuron in collaboration with artist Ai Weiwei. More recently, the Redshank House, a weekend bolthole on the Essex coast designed by architect Lisa Shell and sculptor Marcus Taylor, came wrapped in a warm, spongiform skin of Portuguese cork.
Shortlisted for the 2019 Stirling prize, the annual award for the best building in Britain, Cork House by Matthew Barnett Howland, Dido Milne and Oliver Wilton takes corkitecture to another level by employing it as a total building material. Cork House is just that: a house constructed from solid blocks of expanded cork, like gingerbread or vegan Lego. “It’s purely plant-based, a waste product and from a biodiverse landscape,” says Milne. “Its potential as a building material interested us.” This sparked a six-year research project, conducted with the support of engineers Arup and UCL’s Bartlett School of Architecture, among others. It’s a familiar scenario, architects designing and building for themselves, but the scope and scale of the research programme elevates Cork House beyond the realms of the vanity project, enabling it to punch above its weight as a didactic prototype, despite being the smallest scheme on the six-strong Stirling shortlist.
With huge variations in the scale and type of projects – this year’s contenders include an opera house, a distillery, social housing and London Bridge station – judging the Stirling prize is like trying to choose between a cookery book and a science fiction novel. If Cork House were a book, it would be a manifesto or polemical tract that aimed to radically reframe the processes of architecture and construction through the prism of whole life sustainability, from design to demolition. Buildings account for nearly 40% of global greenhouse gas emissions and are rapacious consumers of resources and energy, yet too often sustainability is seen by architects and clients as just another box to tick.
Cork House turns the conventional design process on its head. “We were interested to see what kind of architecture would develop if we worked from environmentally sustainable first principles and considered each stage of the life cycle,” says Wilton. Made from reconstituted waste cork, which was then shaped and carved by robots, the solid cork blocks create and define the architectural language. Self-consciously “eco-friendly” buildings can often be visually undistinguished, but the strong, simple volume of Cork House, with its rye bread-textured walls, has a curious beauty and rigour.
The project is set in a bucolic riverside enclave overlooked by the Mordor-esque silhouette of Eton College. Eton’s high street oozes oleaginous quaintness, so is, on the face of it, not a predictable setting for an experiment in modernity and ecology. Nonetheless, something radical is going on in the shrubbery. Emerging from its garden site, the house is a long, low-slung pavilion, crowned by a quintet of beehive-like structures. Each is inset with a glazed oculus that anchors the roof like a paperweight, while funnelling light down into the interior. Slotted together without any mortar or glue, like drystone walling, their hefty, stepped forms call to mind ancient Mayan or Mesopotamian structures of stacked stone. Inside, the atmosphere is dark and womblike, shot through with the fugitive gleam of burnished copper and brass used for fixtures and fittings. Soft and slightly spongy to the touch, the cork walls are a reminder of the house’s organic origins and a rebuttal to the brittle sterility and effortful minimalism of so many contemporary domestic interiors.
Because of the risk of flooding, the building is slightly elevated above the ground, impinging very lightly on the site. It’s tempting to think that it could just float away as the waters rise, like a modern ark, but when its time does come the house can be dismantled with minimal environmental impact. As a bio-renewable resource, the cork blocks can either be recycled or broken down and returned to the earth. The aim is to leave no trace. “It’s a provocation, to some extent,” declares Barnett Howland. “We’re not saying that cork is the answer to the construction industry’s problems, but it does point up the need to think about a whole-life approach to buildings.”
Achieving this will not only require a paradigm shift in how buildings are commissioned, designed and made, but also a more profound reconceptualisation of the role of architecture and its relationship with society. Yet in bringing these issues into sharper relief, Cork House shows what might be possible, illustrating the increasingly critical importance of substance as well as style.
