Hybrid wooden CubeHouse rises despite lack of space

At first glance, there is nothing particularly unusual to see from underneath the ingenious scaffolding structure. But if we take a few steps back, and look on top of the structure, we can see a huge 12 m high tower crane disappearing into the air. It is a surreal sight – didn’t we just walk under that? ‘We sure did’, confirms Donnely van der Kamp, project manager at the Visser & Smit Bouw and Homij construction consortium. ‘We’ve got so little space on the construction site for The CubeHouse, that we had to build the tower crane on top of a steel bridge structure. Two trucks can get underneath it at the same time. The construction road is also being used for the renovation of the adjacent office tower The Rock. When materials are being unloaded for The CubeHouse, it’s still possible for a truck heading for our neighbours to get past.’

Building on a space the side of a postage stamp – we use this expression so often within Zuidas that it has almost become a cliché. But only almost, because anybody who walks around The CubeHouse construction site will understand just what this kind of postage stamp looks like. The sides of it are just a few small metres away from the busy Parnassusweg, Claude Debussylaan, the Zuidasdok construction site (where work is underway building the Brittenpassage), and the façade of The Rock. That leaves barely any space on The CubeHouse construction site to store materials. ‘That’s why a lot of materials are now on the first floor’, says Van der Kamp pointing to a pile of metal sheets. ‘We’re continually having to adapt to make use of every centimetre. When we’ve completed one section, we move materials there, freeing up another section where we can continue to build.’

It is not only the construction site, even the structure of The CubeHouse can be described as exceptional. This will actually become the first hybrid wooden office building in Zuidas. The contractor started work on the wooden structure a couple of weeks ago. ‘Over the last year, we’ve built the foundations and the plinth (ground floor) that consists of a concrete structure’, says Van der Kamp. ‘We’re now heading upwards working on the wooden structure. The wood is delivered in batches in ready-to-use parts from a supplier in Austria. We’re putting it together a bit like a Lego kit. Floors, columns and beams, everything’s being built out of wood. Around it, we’re building a façade that’s largely made of glass, which means you’ll also be able to clearly see the wooden structure from outside.’

On the first floor, the first wooden columns are already towering above the concrete structure of the plinth. The wood cannot yet be seen very clearly, because the columns are still wrapped in thick black foil. ‘Because of the wind and rain, we don’t want the wood left outside for too long, otherwise it would become discoloured’, explains Van der Kamp. To prevent that from happening, an unconventional construction technique is being used. Normally, the structural work of the building is the first to be built, and after that – when it is almost complete – the façade will follow. ‘In this case, we’re building both of them more or less at the same time’, says Van der Kamp. ‘As soon as the wooden structure for a floor has been completed, we start on the façade for that floor. This way, each floor is gradually made watertight and the wrap can be removed from the columns and floors. That means that you’ll be able to see the first sections of the façade before Christmas.’

Underneath the roof of the 8 m high plinth, there is still lots of scaffolding. ‘Building the ground floor was quite a job’, explains van der Kamp. ‘The slanted columns on the outside are all made of prefabricated concrete and all of the beams have been poured in situ. This not only involves making concrete: you also need to make the formwork, the appropriate support and ensure that the workplace is safe. This makes the whole process very laborious on such a cramped construction site.’ The beam structure of the plinth, which supports the floor of the first floor and the wooden structure, is around a metre thick and is referred to as a table structure. The structure is made of 60 tonnes of steel and concrete, creating a kind of extra foundation layer. ‘It’s the most laborious part we had to do’, says Van der Kamp. ‘Now The CubeHouse is really taking shape.’