A terrazzo-like precast facade transforms an unloved 1970s office block into one of the financial district’s most prestigious addresses
In Amsterdam, V8 Architects has taken an outside-in approach to revamping a brutalist 1970s office block. A fortress-like six-storey building, originally wrapped in ribbed brown concrete panels, has been opened up with a glazed facade framed by terrazzo-like polished concrete and brass inlays.
“Really, we gave all of our attention to the outside,” says Michiel Raaphorst, director of the Rotterdam-based practice, which has made a name for itself as a creative adapter of Dutch office buildings. “What we’ve learned is that we should consider these buildings as a package of elements with different lifecycles. So with an office building, we actually don't care too much about the interior because the tenants are just passengers in time. They stay for five years, 10 years. They can worry about the fit-out and we can focus on the things that have lasting value.”
The intrinsic value of Prinses Irenestraat 59 (PI59) may not have been immediately obvious to the casual observer. The concrete-framed building had been one of the first office developments in the Zuidas financial quarter but, as towers rose to the north, it found itself squatting on the very edge of the district, a slab-like stepping stone to the low-rise residential neighbourhood beyond. By the start of the century, it was no longer used as an office at all, but was rented out as an international school. Outmoded, unloved and unfit for purpose, it seemed only a matter of time before it was demolished, particularly as it would free up a rare prime site in the Zuidas.
The one thing it did offer that the high-rises didn’t, however, was large floorplates. “This was its unique selling point,” says Raaphorst. With a reinforced concrete frame of flat slabs around a central core, the building included about 4,000m2 of floorspace on each level, offering the promise of flexible layouts, visual connections and spaces for a range of activities. The Covid pandemic, which hit the Netherlands just as V8 began work on the building, merely confirmed the need for new, less confined ways of working.
The architects sought to maximise the rental value by expanding the floorplates and bringing light deep into the plan. Two deep setbacks on the north side of the building, which gave it a distinctive E-shaped form, were not only filled in but inverted, with the introduction of two massive lightwells set forward from the main building line. “The setbacks and lightwells create a lot of different corners and variations in space. You can have open plan in one corner and a cellular office in another.”
The expansive floorplates also meant the MEP designers could spread out the ductwork and cabling, keeping the service zone to an efficient 200mm, and enabling floor-to-ceiling heights of 2.8m. The architects discovered that the basement was the same height as the other floors so this has been converted into office space too, and the surrounding landscape lowered to turn it into a “garden level”. Another office floor was created by moving the top-level plant room into a new setback rooftop structure surrounded by terraces. In all, the reconfigured building – now rebranded PI59 – has 18,750m2 of lettable floor space, a 35% increase.
Externally, the building softened into what Raaphorst calls “elegant brutalism”. The hard corners of the floor slabs have been sawn into curves, with rounded floor-to-ceiling glazing following the same perimeter line. In front of this, the rough, blank concrete of the original facade has been sublimated into a refined framework of polished precast elements.
At ground level, the panels are fluted – achieved by adding timber slats to the moulds – and acid-etched in an echo of the ribbed aesthetic of the 1970s cladding. But the finish is lighter in tone, thanks to the use of Norwegian white marble aggregate, and more controlled.
From the first floor up, the solid panels give way to a more transparent grid of columns and beams. Blue-grey marble aggregate, in sizes from 25mm to 40mm, creates the terrazzo effect, while one side of each column has been scooped out and inlaid with brass. “It’s really to emphasise the softness. You cut out a corner and it’s almost like ice cream,” says Raaphorst.
The facade is self-supporting and mounted with a steel fixing system to the edge of the floor slabs, isolated by a thermal break. The joints between the various column and beam elements are clearly articulated – a way of navigating the deviations in size and varying tolerances of the original frame. “The building looks very neat but there was a lot to solve. The more components you have, the more chances you have to resolve small differences, so the facade has a lot of horizontals and verticals. Normally architects are a little bit afraid of joints, but here the joints are really designed – almost more than the elements between them.”
V8 worked closely with precast manufacturer Decomo from very early in the process to make sure their ideas could actually be realised. “The facade you see now was designed in the very early weeks. That meant we could then go to suppliers and manufacturers to discuss how to make it, rather than wait until a technical design phase.”
A mock-up of a bay was made to test the connections between the different elements and two dummy columns were cast with four different sized scoops (the radius of the scoops gets larger as the building rises, while the horizontal beams get thinner). These were delivered to a coppersmith, who could then work out the best way to shape and fix the inlays. This involved welding pins to the back of the brass shells, which were fitted on site into recesses in the concrete.
The brass, Raaphorst points out, will age and weather with time – all part of the process of softening a once-brutalist fortress.