Striking facade of galvanized steel for The Silo

And also a long and maintenance-free lifetime

Galvanized steel as a sustainable, circular but also architectural cladding? We find a very striking example in Denmark. The Silo is a former concrete grain silo that was transformed into an apartment complex and given a new overcoat of galvanized steel. A landmark for the capital Copenhagen that attracts a lot of attention, even in architectural circles.

The qualities of hot-dip galvanized steel are well known, with undeniable number one being its long and maintenance-free life. For more than 150 years, this honest and natural marriage of zinc and steel has proven that this material is extremely resistant to corrosion. Galvanized steel also excels in the various phases of its life cycle - make, use, remake/repair and recycle - showing itself to be a sustainable building block of the circular economy. That there are also surprising aesthetic possibilities is already evident in this special project by Danish firm COBE. 

Inform and inspire

"Despite its many qualities, galvanized steel facades are still rather uncharted territory for many architects," says Hans Boender, Technical Expert at Zinkinfo Benelux. One of the aims of this umbrella trade organization is to inform and monitor. For example, all the thermal galvanizing companies that are members of Zinkinfo, generally family-run companies of Belgian and Dutch origin, offer up to 30 years of warranty on their galvanizing, depending on the product and application. "Zinc is also an honest material, by the way," Boender adds. "What you see is what you get, so no hidden defects." Inspiring is also part of the mission. One way Zinkinfo does this is with a fine publication, released in collaboration with its European sister organization, about this remarkable Danish project completed in 2018. We are already lifting a tip of the architectural veil and highlighting The Silo.

Complex facade geometry

The port area of Nordhavn in Copenhagen is undergoing a true transformation and is completely revived. Former industrial buildings are giving way or being transformed into contemporary architecture. A striking example is The Silo, a 50-year-old concrete grain silo that was transformed into a 17-story residential high-rise, with a restaurant at the very top with 360° views of the surroundings. "We wanted to preserve the spirit of The Silo as much as possible - both in terms of its monolithic exterior and majestic concrete interior - by simply giving the building a new overcoat," said Dan Stubbergaard, architect and founder of COBE. The result: a building with an avant-garde look, not least because of the complex facade geometry combined with galvanized steel that helps define the building's identity. 

Industrial heritage

In terms of cladding, COBE was indeed looking for an "honest" and "lively" material that connects with Nordhavn's industrial heritage. After extensive studies and weighing the pros and cons of steel versus aluminum, the choice finally fell on 3 mm thick façade panels made of discontinuous hot-dip galvanized steel. For the balcony balustrades, the steel sheets were perforated before galvanization, creating a particularly graphic and semi-transparent effect. The final choice was based not only on the more interesting and raw character of galvanized steel, but also on a comparative cost calculation and the independent Force Institute's advice regarding life expectancy. An informed decision, with the desired aesthetic result.