Platform on new construction, renovation, restoration and transformation
On Coolsingel in Rotterdam stands an office building in which two layers of time come together. A bank building from the 1960s with an extension from the 1990s. To meet strict future sustainability requirements, Paul de Ruiter Architects is now adding a third time layer, resulting in a municipal monument that is ready for the future and meets Paris Proof standards.
C93 was in use at ABN AMRO for many years. As with more large organizations, the way of working changed: fewer people in the office, more flexibility. The bank decided to sell the property and rent part of it back. For this project, Paul de Ruiter Architects worked with De Vries en Verburg Bouw, IMd ingenieurs, Linssen, Peutz, Tank, Moss, Crimson/Jan-Willem Walraad and Bouad, among others. During the process, the building was designated a municipal monument. Notable because the complex is relatively young. Architect Martijn van Gameren of Paul de Ruiter Architects explains: “Precisely the combination of the original design by architect Van Nieuwenhuizen and the extension by architect Van Erk was the deciding factor. Two layers of time that are carefully interwoven. The extension from the 1990s left much of the older building intact and respected the existing structure. That made the whole thing special enough for protection.’
Together with owner and developer BNP Parisbas Asset Management and Provast, the design team decided to keep as much of the existing shell as possible in the current renovation. “We don't like to demolish. Leaving as much as possible in place saves material and prevents additional CO2 emissions. Our addition to the building is mainly in the sustainability layer,” Van Gameren said. The atrium was given a new shape. Where previously there were mirrored walls, now daylight enters again. And the facade openings have also been enlarged. “That makes for more pleasant work floors and less need for artificial light. Moreover, fewer lamps means less energy consumption,” Van Gameren explains.
C93 will soon be Rotterdam's first Paris Proof monument. “As an agency, we are very proud that we have succeeded in making this monument sustainable. This is now completely interwoven into the building, making it ready for the future. So that means not only an aesthetic new image, but we have also improved everything under the hood. From low energy emissions to sustainable materials. And that with a building that was already there in the 1950s.’
The tower grows from 80 to 100 meters high. The two heaviest upper layers were removed and replaced with lighter structures. “This keeps the load on the foundation down. Many parts of the existing facade have been dismantled, cleaned and restored. Then they return at a greater height.” So do the distinctive ‘cow eyes’: the large, oval windows in the top gable. “In the 1990s, behind these windows were the boardrooms. At 80 meters, a lot of exciting deals were made. We have now put the windows back at 100 meters. They now have a whole new perspective of the city again.’
Another striking detail is the reuse of the natural stone facade slabs. The salmon pink marble slabs, Pantera Rosso, had been hanging there for thirty years. They were poorly insulated and partially damaged. “Instead of disposing of them, they were ground up and re-pressed into thinner slabs with almost the same appearance. This preserved the appearance and gave the building a better insulated shell.”
For the city, the first floor is especially important. “The entrance on Coolsingel had been closed for twenty years. That will be reopened and made transparent and given a public function. This will give the building a face to the street again.”
