How do the three spatial elements of the new port house – the existing building, the new extension and the concrete bridge – relate to each other?
Looking at the existing building and the new building as a whole, we like to see them as two entities, where one cannot work without the other. The existing building provides the base for the entire project, it is not something we dismissed, we see it as an equal part of the constellation. Despite the very different nature of the two buildings, we have been trying to give the same qualities of space to both the existing and the new building. In order to connect the two programmatically, we applied some kind of sandwich-concept, whereby we have chosen to put all the common program such as auditorium, restaurant, foyer and meeting rooms, in the middle of the building, so they are organised on the top floors of the existing building and on the bottom floors of the new building. We proposed the concrete bridge as a third element, which had not been part of the competition brief. In order to break and shift its volume, we suggested to create a multi-purpose external environment, a viewing terrace for multiple use above the existing city fabric and with access to the restaurant. Obviously there are various views to the port and to the city from up there. Looking down through cut-outs in the bridge one can see the square in front; looking up, there are windows that expose some of the interior of the new building – it is a very three-dimensional, spatial environment.
How did your office approach the re-design of the existing pre-war building, technically and formally?
Zaha was very interested in layering, in working with the existing building. We chose to respect the existing, listed building as much as possible. Both the external and internal facades, the courtyard and the staircases were still very much intact, most of the original interior, however, had been already changed throughout its former use as a fire station. We very much followed our heritage consultant when it came to the renovation, we gave them the lead on what we could or could not do; there was a constant dialogue with heritage consultants and with heritage authorities. We restored all the facades in a very low-tech way. The brickwork for example is very much patchy and you can read historically what has happened, because we did not want to damage the fabric of the brickwork too much. The doors were kept original, where possible, where not, we made copies. For example, we automated the massive doors between the atrium and the reading room, which used to be the hall for the fire trucks, and we automated these. So the technical system is new, but the doors are kept intact as much as possible and we worked with the original framing.
The new extension seems to float on top of the existing one. Are the two volumes structurally connected at all?
Structurally, we tried not to interfere too much with the existing building, the structure of the new building is completely independent. However, there is a new element we brought in, that has an impact on the existing structure: the new roof of the previously open atrium is supported by the brick walls of the existing building. The weight of the new building is fully carried by two concrete columns, one is central in the atrium, and one is, inclined, positioned in front of the building. The concrete bridge connects the two columns on top, while there is an underground connection as well. Basically, a vertical ring out of concrete goes over and under the South wing of the existing building to support the new building. The black columns inside the atrium space provide lateral stability.
The facade of the new building is one dynamic surface. What is the underlying conceptual intention of the transition on its surface from flat to rippling, from transparent to opaque? What design technique did you apply?
We wanted the new volume to have a dynamic appearance in contrast to the static dignity of the existing building. To reinforce this dynamic in addition to its geometry, we wanted it to appear as if in motion. By triangulating the segments of the facade, we created the transition from flat to more cracked. Initially, at the competition stage, this was a kind of random pattern. Throughout the process, we were collaborating with our local architect, the facade constructor and Schüco to develop a realistic concept that would meet both aesthetic and economic expectations. We made an analysis of how many different modules we could afford, how many modules we would need to keep the random effect and not to see repetition throughout the building.
In the original design of the existing building, there was a tower included which had never been realised. What role did this tower play in your design?
When our heritage consultants came up with the original design, which had this very tall, ornamental tower, we thought this original intention would justify a vertical element on top of the existing building. The fact that the existing building does not have a main facade, but rather four equal facades, which is quite exceptional for a building from that time, is another reason why we immediately thought it would be interesting to put something on top and not build something in front, because it would block one of the facades.