.jpg)
The area around Stadionplein in Amsterdam has undergone a metamorphosis in recent years. Not only have the Citroën garages been renovated and rezoned, but new buildings have also been built on the square. Zuidblok – a design by Kollhoff & Pols Architects – has an unconventional shape that incorporates an enormous cantilevered canopy. Above that, two solid building layers are clad with white glazed bricks.
The master plan for the redesigned Stadionplein was clear: the new buildings needed to look as though they were ‘attached” to the two Jan Wils Citroën garages: the southern building with white impregnated brick dating from 1931 and the white plaster garage from 1960 beside it.
Kollhoff & Pols Architects won the design competition for the Zuidblok: a compact box incorporating a catering plan (a restaurant below and a hotel above). A compact, white box.
‘We said from the start that a completely white stucco facade was undesirable in our opinion’, explains Alexander Pols. A design team was formed for the plans around Stadionplein. It included supervisor Wouter Veldhuis on behalf of Stadsdeel Zuid, West 8 for the layout of the square, Dam & Partners Architects for the block on the north side and Pols for the Zuidblok. ‘Many discussions about materials took place’, says the architect. ‘We arrived later. Diederik Dam had already chosen travertine for the plinth of his building. It was logical for us to incorporate that choice in the Zuidblok plinth.
Material samples are lying on the table: a piece of travertine, a white stucco plank and an ivory coloured glazed brick. ‘The discussion soon turned to the colour of the materials, also indicated by the Welstand and Monuments Committee. They all thought it was extremely white. They also saw the practical disadvantages and suggested that the palette be refined. This gave us more room to choose materials, textures and colours’, continues Pols.
‘Hans Kollhoff and I sat down together at the table. Here, at this table. We reviewed the different options and studied the materials. Hans came up with the idea of Berliner Pfeifenköpfe: ivory white glazed bricks that you often see in Berlin’s inner courtyards dating from around 1900. The name refers to ivory coloured pipe ends, that were used a lot in those days. In Berlin these bricks were used primarily to capture as much light as possible in the dark courtyards. The rough bricks, often with a craquelé glaze, gave the walls an almost industrial look. ‘We thought it was a nice reference’, recalls Pols. ‘Functional, industrial: a lovely match for the light yellow bricks of the residential buildings of Berlage near Zuidblok and the architecture of Wils. The idea was embraced by everyone in the team.’
The quest for the right brick then started. We quickly opted for a standard size. And for white clay in a molded version with a sanded surface. For the glaze, Wienerberger made different samples in order to determine the colour and gloss level: in the end, sample 21 was chosen. Its presence on the table was undeniable. ‘The glazed brick is manufactured according to the double-fired system, which makes it an expensive construction material. I’ve never worked with such an expensive brick before!’ smiles Pols. A glossy, white brick that is white underneath: it turned out to be exactly what the architects and monument commission had in mind.
But the choice of brick was not yet complete: the bonding pattern, pointing method and cement colour were examined. ‘You obviously want it to be an even surface and to be an abstract and solid block,’ the architect explains. ‘The way in which the window frames are positioned in the facades also contributes to the appearance. We really searched for a contrast. All the frames are the same: we wanted to keep the palette to a minimum.’
The pointing turned out to be the biggest challenge, especially at the dilatations. ‘You don’t want any visible dilatations, no deviations in mortar or colour. It needs to be visually cohesive’, says Pols. A total of six vertical dilatations were required for each facade. The construction of the structure made it even more complicated: a steel structure with an enormous hinged bridge girder for the cantilever. ‘It all moves! You also have to deal with settlement of the building: it bends slightly at the cantilever. A toothed dilatation was chosen fairly quickly. We then conducted endless trials.’
In partnership with contractor Vink Bouw, we looked mainly at how invisible depth could be built in using the depth, colour and finish of the mortar. ‘Using light-grey and beige mortars first, before we finally opted for a slightly darker mortar. We experimented with recessed pointing and even open pointing at the dilatations. Eventually, a sanded sealer mortar was selected – aesthetically, it was the best solution.’ During a recent tour, the architect was able to satisfactorily establish that it works: the Zuidblok superstructure has the appearance of a gleaming whole. The building will not settle any more, so mission accomplished? ‘The trained eye is more critical’, he smiles. ‘But then I know where those hinges are.’
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)
.jpg)