For centuries, the bark of the cork oak was so synonymous with a single application that it lent its name to the product: the wine cork. Today, about sixty percent of all harvested cork is used to stop bottles, although its share in that market has been challenged by a burgeoning trend toward screw caps. The remaining forty percent of the cork industry is geared toward a wide range of other applications, from shoes to the cores of baseballs to insulation in NASA’s rockets. But for most of us, non-wine cork is still relegated to bulletin boards and the occasional floor tile.
Considering the myriad properties of the material, it’s a wonder that it hasn’t been adopted for yet more uses. Naturally, hydrophobic, lightweight, durable, and easily malleable, cork is an excellent insulator for both heat and acoustics, a capable fire retardant, and is resistant to mold. In recent years, designers and builders have begun to take note of cork’s possibilities, producing everything from impressive lighting fixtures to breathtaking modernist seating.
However, cork’s most impressive unconventional use may be in its use cladding entire buildings, where the material feels right at home. Cork facades have an organic and warm quality, finding harmony with both urban and natural surroundings. Interacting with the weather, cork also changes color over time, taking on a patina that can vary from plank to plank. Plus, its insulating properties help reduce climate control costs dramatically.
In Berlin, Rundzwei Architekten’s aptly-named Corkscrew House stands apart from its neighbors, a monolith of cork. Stark and geometric. its organic exterior is at once precise and soft-leaning far from the brutalist trappings of concrete. And, as one might hope, a grand spiral staircase in the center of the 3,200 square-foot house completes the allusion to its namesake.
The panels that clad Corkscrew House’s walls and roof were produced by heating and pressurizing waste cork granules from the wine industry-a process that requires no additional materials thanks to a naturally-present resin in the cork. The resulting slabs are durable, flexible, and easy to work with, allowing workers to use traditional woodworking tools.
Perhaps cork’s most attractive quality, though, is its unmatched sustainability. As the bark of Quercus suber trees, cork is harvested rather than felled, leaving live trees that will produce more cork every nine years for up to three hundred years. About half of the world’s cork is produced in Portugal, where its harvest has been well-regulated and revered for centuries. Cork is cut by hand from mature trees by skilled workers who are paid a living wage. Thanks to the cork forests’ highly-effective absorption of carbon dioxide, the cork industry is actually net-carbon-negative. One might make the argument that cork is the world’s most sustainable building material. Its only limiting factors are the time it takes to grow it and the climate required to cultivate its trees-limited to Southern Europe and Northern Africa.
In London, the aptly-named Studio Bark has taken cork construction to a new extreme with Cork Studio, a garden shed built entirely out of the material. Here the cork makes up not just the cladding but solid blocks used to form the structure. Describing the process, Studio Bark’s architect notes that cork’s qualities “eliminate the need for frames, linings, glues, tapes, breather membranes, and wet trades,” making the project particularly cost-effective, sustainable, and even biodegradable. Unlike many buildings, Cork Studio has an end-of-life plan, able to be tossed onto the compost heap once its usefulness has run its course.
Today, cork remains a relatively niche building material, limited mainly by its cost of transportation and perhaps a lack of imagination. However, if screw caps continue to make in-roads into the wine industry, we may be lucky enough to see more corkclad buildings sprouting up around us. At once incredibly traditional and refreshingly innovative, it’s an age-old material with tons of life left in it.
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