Sometimes, the best option is one on top of the other. It might be because available space is too constricted, because an opportunity is too good to be wasted, or simply because it feels good, but lately we are seeing a number of buildings that have been built on top of other buildings. Two recently completed examples by well-known regulars of the starchitectural press include the Elbphilharmonie in Hamburg by Herzog & de Meuron, an auditorium built atop an old warehouse; and the Port House in Antwerp by Zaha Hadid Architects, an office building which incorporates an old fire station.
Both of these buildings are in ports, where land is scarce, so lack of space is likely the rationale behind the stacking of these buildings. They are also in northern Europe, where architecture must at times compensate for the flatness of the landscape and where there is a certain licentiousness in the culture that makes these kinds of encounters more acceptable.
Here, on the other hand, we have a more culturally “uptight” example:
It’s a proposal for three buildings (!) on top of Vancouver’s former Canada Post building, which dates from 1958 and enjoys heritage protection. As can be seen by the bulkiness of the volumes being added, the rationale here is clearly the opportunity presented by a flat-roofed building occupying an entire city block in a city with some of the highest land values anywhere. It is evident, from the clunkiness of the design, that this part of the world is less experienced in these matters.
The city with the most buildings on top of buildings is probably Barcelona, where much of the famous 19th century “Eixample” urban expansion plan laid out by Ildefons Cerdà has been getting vertical extensions since the 1960s. The city’s Franquista mayor during that period, Josep Porcioles, was notoriously lenient when it came to applying the city’s building bylaws, and so extra floors, attics, and penthouses were shamelessly added to the tops of buildings throughout the city.
Barcelonians popularly refer to these added structures as “barrets”, or hats. They are everywhere. Some are more discreet, while others, such as the above example, are more scandalous.
Of course, in the most ancient cities, buildings have always been built on top of other buildings. It’s just that the buildings on the bottom were usually ruins resulting more often than not from merciless sackings and invasions. Today, of course, we are much more civilized and no longer tolerate such barbarism, so buildings are more frequently built atop of still-standing buildings.
Here, it’s important to remember that whenever a building is designed to be mounted on top of another building, the one beneath has to be reinforced so that it is structurally capable of withstanding the added pressure. Always practice safe architecture!