Ecca collection

The reason is the cladding material that architect Diederick Dam of Dam and Partners chose for the tower. A total of 22 different shades of aluminium cladding combine apparently seamlessly to give this fading effect, becoming lighter as one’s eye travels upwards. This is in deliberate contrast with the lower tower, which is clad in black metal, its solidity forming a counterpoint to the evanescent nature of its taller companion. The base of both buildings is clad in a deliberately heavy anthracite-coloured stone. The two towers are set at an angle to each other, with a glazed lobby between them.

Every architect wants their building to look good from the outside, but the form of this one and its relationship to its surroundings were of especial importance, because it occupies a key, even unique, position in the city. At 165m tall, it forms the summit of the city’s South Bank development, and sits on the waterside beside the Erasmus Bridge.

The angles between the buildings allow them to align themselves with both the streets and the water. Having chosen his cladding strategy, Dam had to be confident that it would work exactly as he had conceived it. The idea was not to have continuous graduation but to ensure that by the time the taller building emerged from behind the other one there was already a strong contrast. ‘We did elaborate tests on how we should go ahead,’ explained Dam.

‘A grey colour can be quite harsh if you specify too many blue tones,’ said Dam, so in fact the building is in shades of a warmer, browner grey. The aluminium panels were the tallest that Dam could get, at 3.5m tall each spanning a storey. And they are extraordinarily flat – ‘even flatter than glass’ says Dam. The panels were also given a special finish, to enhance their reflectivity and uniform qualities. Dam is impressed by how much the technology has advanced. ‘The depth and quality of colour is so much better than it was 10 years ago,’ he said. Silvery steel fins provide a subtle contrast, changing as one moves around the building, since they are less apparent from face on than at an oblique angle.

The building was designed for occupation by accountancy firm Deloitte. They must be delighted to have such a handsome building in such a prominent position, and will enjoy the spacious glazed area between the two towers. But equally important for an occupier will be the building’s sustainability credentials. ‘Everybody talks about sustainability now,’ says Dam, ‘but you don’t often see skyscrapers being sustainable’. The building has picked up sustainability awards, chiefly because of the way that it uses the water of the Maas River to regulate temperatures. Like all bodies of water, its temperature fluctuates less than that of the air, so that it is warmer in winter and cooler in summer.

Dam, whose office is in nearby Amsterdam, is pleased with the way the building is perceived. ‘One of the things I like most,’ he says, ‘is that people from Rotterdam regard it as a building that suits the city.’