Stedelijk Building News nr. 2 

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Karel Appel in the ‘Appel Bar’, 1951

Restorer Louise Wijnberg at work

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Controversial work

In 1948, Karel Appel was asked to paint a mural in the staff canteen at Amsterdam’s City Hall (then on the Oudezijds Voorburgwal). His large semi-abstract mural entitledQuestioning Children was completed in March 1949 and immediately caused a furore. The council workers didn’t like eating their lunch under the accusing stare and begging hands of starving children and anyway didn’t care for that kind of modern art.

There were critical press reports expressing a lively distrust of abstract art and the mural itself was damaged by staff pencil-ling graffiti on it and even hurling things at the wall. By 9 December 1949, the municipal executive had had enough: it decided to cover the mural up and in 1950 it was papered over.

As a kind of compensation for this bruising episode, the then director of the Stedelijk Museum (Willem Sandberg) commissioned Karel Appel to decorate the walls of the museum coffee bar. The many doors leading to it show that the cube-shaped room was then an important crossroads in the building. The assignment gave Appel the opportunity to create a kind of three-dimensional painting. After several months of study and preparatory work, during which he produced not only various sketches but also a painting, Appel started to cover the walls rapidly, working in his usual direct and spontaneous way. He painted the whole surface of each wall, electricity sockets and all, and even the room’s doors, roll-down shutter and ceiling. Apparently, one day he arrived to find a message from Sandberg saying ‘Karel, aren’t you going a bit far?’ 

Appel used Keim mineral paints, in which the mineral pigments are mixed with water glass (potassium silicate solution). Once dry, these paints form a perfect bond with the plaster surface of the wall. Here and there, it is still possible to 

Keeping an eye on Appel 

Louise Wijnberg has been a restorer at the Stedelijk ever since late 1986 and is a real Karel Appel fan. Twenty-two years ago, her first job was to help her colleague Elisabeth Bracht restore the Appel Bar, which had then been used for some time as a storeroom. Ever since the current restoration of the Stedelijk began in 2004, she’s been paying weekly visits to the Appel Bar and the Appel mural to check the climatic conditions around them. The aim: to ensure that the new Stedelijk has two beautifully restored works by Karel Appel to show the public!

Cartoon showing protesting council workers

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make out the black underdrawing, which he later coloured in. The lively figures of children and animals seem to float and swim in space all round what quickly became known as the ‘Appel Bar’.In 1956 the artist was commis-sioned to create another mural for the museum, in the restaurant. This time he incorporated an unusual rosette-shaped glass appliqué – then an entirely new idea – into the painting. In the late morning, the sun shone directly in through the coloured glass, flooding the room with a warm glow.

Even within the museum, apprecia-tion of Appel’s work has fluctuated over time. In the 1980s, the Appel Bar was turned into a storeroom, although the mural in the restau-rant remained a prominent and much-loved feature. The artist’s signature and dating of the work were once even painted out. They were uncovered again by Wijnberg and Bracht in 1987 but still look a bit washed out.

Appel fully protected

It was very important to the Stedelijk that the Appel Bar and the mural in the restaurant should be fully protected and preserved during the current renovation of the museum. Advice was sought from Robert Crèvecoeur, a specialist on murals at the Netherlands Institute for Cultural Heritage (ICN). How was the climate in the vicinity of the works to be kept stable and frost-free? And how could they be protected from dust and damage? The safety of the works was ensured by sealing off the Appel Bar and installing a screen wall in front of the mural in the restaurant, so that it too was sealed off in an enclosed space. Both spaces were equipped with thermo-hygrographs (devices that measure and record current temperature and relative humidity). The climatic conditions could be effectively controlled by humidifiers and dehumidifiers and through the use of a small heater.

So the climate around Appel’s murals had been controlled but a 

way still had to be found to protect them from vibration – no easy task on a building site where structures were to be demolished and piles driven. Devices were mounted on the walls to measure vibration and sound the alarm if it exceeded a certain level.Ever since the start of building work, Stedelijk restorer Louise Wijnberg has carried out weekly checks, sometimes with the assistance of Aad van der Elst of the museum’s technical services department. At times, concern was such that she was checking twice a week and once even non-stop for an entire day! 

During the first year of renova-tion work (in 2004), there was a lot of heavy demolition work and intensive drilling activity in the area around the Appel Bar and the restaurant mural. Whenever there was too much vibration, the devices sent an automatic SMS to warn building supervisors Philip Nijman and Bob Looijenga or site manager Ton Woud (Midreth). They then rushed over to check what was happening and occasionally even had to call a halt to building work. Usually, it proved to be a false alarm, generally caused by a passing tram. But sometimes, the warning had to be taken seriously. For example, a mezzanine floor 4 metres up and adjacent to the Appel Bar had to be actually sawn out because demolishing it with a jackhammer would have caused too much vibration.

The restaurant mural is on an outer wall and was therefore more vulnerable to climatic fluctuations than the Appel Bar. Some particu-larly vulnerable sections were given extra protection by the traditional method of covering them up with rice paper and paste. The rice paper has now turned yellow due to the nicotine that had permeated the walls of the restaurant and the mural over the years.

The old ceiling adjoining the restaurant mural has been a parti-cular problem during building operations. Part of the ceiling 

The glass appliqué rosette in the Appel mural

Karel Appel’s signature

The thermo-hygrograph measuring humidity and temperature

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structure was embedded in the wall that bears the mural; cameras were used to see how it could be removed without damaging the painting but it was eventually decided that the risk was too great. For safety’s sake, the part of the old ceiling adjoining the wall is being left in place.The gallery of the former library was also fixed into the wall bearing the mural. However, this proved easy to remove. The resulting holes and other scars in the walls painted by Appel are shortly to be restored by Ton Evers, who has been employed by the Stedelijk as a painter for the last seventeen years and has worked as a restorer on major historic buildings like the Nieuwe Kerk.

Thanks to the alertness and expertise of the building supervi-sors and site workers, the historic Appel Bar and Appel mural have been protected throughout the building operations and have survived virtually undamaged. Following restoration and cleaning, they will soon be on show again in all their glory. There are plans to commission a pendant to the Appel mural, in the shape of a new mural by a present-day artist, to be executed on the opposite wall of the former restaurant. More news about this in due course.

Karel Appel perched in front of his mural, 1956

From left to right: Louise Wijnberg, Ton Evers, Philip Nijman, Ton Woud, Aad van Elst and Ronno Stegeman

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Aryan Sikkema, building works coordinator for the Stedelijk Museum, explains:“At its largest point, the bathtub, including the awning, is 100 metres long and 40 metres wide. The actual bathtub, containing the exhibition spaces, the auditorium and the video/film theatre, is a bit smaller. This whole colossal object is a bit like some UFO come to earth and it’s going to be supported on just four columns and a concrete wall. However sturdy they may be, columns can move horizontally, so the building needs to rest on what’s called a ‘stiff element’: in this case, the concrete wall, which will carry on down into the foundations. That’s what will give the new building 

its strength. First of all, hundreds of piles were driven into the clay under Amsterdam. Then a thick concrete floor was poured for the basement, with extra-thick areas in it to support the columns. These areas are themselves supported by extra piles, as is the stiff element (the concrete wall). That extra strength in the foundations is essential because all the vertical and horizontal forces in the building are going to be conducted to the four columns and the wall via a steel frame. So they must be able to take it.

In every building there are forces at play and you have to take account of them. The bathtub is like a bridge, which also has to span a distance. Crossed steel girders like in an old-fashioned railway bridge are the simplest way to do this and the steel frame that’s now being built resembles that sort of bridge. This steel frame is, as it were, a composition made up of large and small triangles which 

distributes the forces, just like the timber frames in some houses in Southern Germany and Austria. The sloping wall of the bathtub will be supported and held in place in exactly the same way.

The components for the steel frame will be delivered in the spring. It will take hundreds of vehicles, because a 6-metre segment is the most a lorry can carry. The components are like enormously heavy bits of meccano that can only be fitted together on site, using huge bolts. The steel frame will form a skeleton which then has to be covered with the famous composite and finally given a shiny white coating to make it look exactly like a bathtub. “You’ll never be able to see the structure of the building as you can now”, Sikkema grins, “so go and take a look while you still can –there’s a great view of the site from the ‘donkey’s ear’! But films of the construction work can also be seen on the Stedelijk website and on YouTube.”

Benthem Crouwel

dwarsdoorsnede D-DHet Nieuwe Stedelijk MuseumCross-section of the Stedelijk Museum. On the left, part of the original building; on the right, the ‘bathtub’ in its steel frame

The new building, current status:  the steel frame

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Facts & Figures The restoration of the original building and the construction of the new one have taken vast amounts of material. Some key figures:

- 52,000 cubic metres of soil were excavated for the new building - the museum is gaining an extra 8,000 square metres of exhibition floorspace - 4,800 cubic metres of concrete was poured under water for the floor and walls

of the basement - in the original building alone, there is no less than 10,000 square metres 

of exhibition wall space - the construction of that wall space has taken:

20,000 square metres of 12 mm birch plywood for the front of the facing walls 10,000 square metres of chipboard for the back of the facing walls 49 kilometres of steel profile to make the walls 4 kilometres of ventilation duct

- specialist workmen have laid 65,000 marble blocks, each measuring 1 square centimetre, for the restoration of the granito floors on the ground and first floors of the original building

- the granito floors laid in 1895 have been restored so far as possible to their original condition. The Netherlands has few experts in nineteenth-century granito flooring; they have all been employed to restore the hall and staircase to their former glory.

- the elevator pit for site delivery vehicles is 9 metres deep - every day there are 120 to 150 construction workers on site - the outer walls of the bathtub measure 2800 square metres

To construct the new building, 52,000 cubic metres of soil had to be excavated. Since trenches fill with groundwater once they are more than five metres deep, further excavation work had to take place under water. The concrete floor on which the building sits had to be poured in a single operation, likewise under water. The operation was scheduled for one weekend in November 2008 (the constant flow of vehicles bringing the concrete would cause least congestion in the weekend and they would themselves suffer least disruption from other traffic). A special route was blocked off in consultation with the municipal district authority and 300 concrete mixer lorries drove in and out all weekend, round the clock, from 5 p.m. on Friday to 5 p.m. on Sunday. The concrete was poured with the help of long tubes and various teams of Belgian divers, whose job was to 

smooth it out at the bottom of the water-filled trench. The concrete was then cured under water and finally all the water was pumped away. As luck would have it, there was already a conduit leading from the ice rink on the Museumplein to the Boerenwetering canal, so it was a fairly easy job to drain the trench into that conduit. However, draining the trench that way would take about two to three weeks and, because of contractual obligations towards the rink operator, the rink had to be allowed to open before that; otherwise, large sums would have to be paid in compensation. In consultation with the local water authority, it proved possible to empty the trench more rapidly via an extra drain in Van Baerlestraat and the ice rink was able to open exactly on time. After that, the concrete had to be reinforced with steel. And the bending of the wire mesh is a job best done with bare hands – in the bitterly cold winter of 2008-2009... all praise to the steel fixers!

How to lay a floor 

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A long concrete T-beam being manoeuvred into place to support the roof of the basement and the paved pedestrian area above

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The three parties around the table are: 

– The user of the building: the Stedelijk Museum, represented by its director Gijs vanTuyl. He is responsible for artistic and use-related choices: “For me, the only thing that matters is to create a practical place to house works of art. Plenty of museums are good as architecture, but not good as places to keep and show art.” [GvT]– The building works coordinator appointed by the museum, AryanSikkema: “I am the link between the museum, the City authorities and the construction companies, and my job is to ensure that they deliver the best possible quality for the users of the new building.” [AS]– the client for the restoration project and new extension, and future owner of the building, the Project Management Bureau of the City of Amsterdam, repre-sented by project manager Bas van Stratum: “As the City’s repre-sentative, I want to achieve a high standard building for the user (the Stedelijk Museum) and the general public. In that sense, I can be said to represent two parties: the alderman and the museum. In doing so, I have to take account first and foremost of two important preconditions:funding and planning.” [BvS]

After the introductions, the discus-sion can begin. 

1. The escalatorThe issue: the escalator is to go straight from the basement to the first floor with no stop on the ground floor.

Gijs van Tuyl: “The long escalator was an important feature of Benthem Crouwel’s original archi-tectural design: a strong diagonal line acting as a counterweight to the façade. To begin with, I was very sceptical about the absence of a ground floor exit; I doubted whether that was user-friendly. In the original design, Mels Crouwel had also turned the grand staircase around, away from the Paulus Potterstraat entrance. But 

Critical Choices,  an interview 

Renovating a museum and building a new extension is never going to be a piece of cake. To give some idea of the choices involved, this interview offers a glimpse behind the scenes at decisive points in the construction process. What were the hottest issues? Who had to be convinced of what? Based on six concrete examples, this interview explains why the museum will soon look the way it does.

Gijs van Tuyl, director of the Stedelijk Museum

Aryan Sikkema, building works coordinator for the Stedelijk Museum

Bas van Stratum, project manager at the City of Amsterdam’s Project Management Bureau

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I was keen to keep that entrance, for example for groups to use, so the familiar grand staircase had to stay the way it was. We looked at all sorts of alterna-tive plans for the escalator; first it was in, then it was out – in the end we were fed up with the whole thing! Of course, installing such a long escalator is pretty expensive, so we were keen to find an alter-native. In the end, though, Mels persuaded us that it really will be better for visitors not to have to return to the entrance hall once they’ve bought their tickets and hung up their coats. The escalator will take them from the first floor straight down to the basement without breaking the spell of the exhibition. And we can see straightaway in the case of our opening Mike Kelley exhibition that the effect is going to be really theatrical, so I’m glad he finally won me over.”

Aryan Sikkema: “Perhaps I can come in here and say that Mels finally convinced me when he pointed out that the entrance hall is now going to be quite small compared with the original design, because Gijs wanted more exhibi-tion space for the museum.The hall is going to be crowded enough without finding room for an exit from the escalator; it might even interrupt visitor flows and cause congestion. We looked at every aspect of the issue and examined four different design options before finally coming back to the original idea of the escalator. The new building is also meant to serve as an icon and this long escalator will be an important eyecatching feature within it.”

Bas van Stratum: “For me too, the clincher was the idea that visitors could remain under the spell of the exhibition without having to traverse the busy ground floor area. The route will be more restful for them and that’s important. But perhaps it will create extra suspense too, as visitors see the escalator from outside and wonder how on earth to get onto it. Time will tell.”

Benthem Crouwel

langsdoorsnede B-BHet Nieuwe Stedelijk Museum

The escalator linking the first floor and basement in the new extension, with no stop on the ground floor

The grand staircase by the old main entrance

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2. Breaking through from the Reception Room The issue: two entries to the new extension have been made by making apertures in the back wall of the grand Reception Room in the original building.

GvT: “That was my idea. I first be-came familiar with the Reception Room when I worked at the Stedelijk as a curator [1969-1976, ed.]. It always posed a bit of a prob-lem for exhibition design because it’s such a cul-de-sac. It broke the momentum because visitors had to walk round it and out the same way they came. Wim Beeren thought so too, by the way; it wasn’t just me. In Mels’ original design the doorway to the new extension was tucked away beside the Reception Room. I asked him to change it and he was very enthusiastic about the idea.”

AS: “I could see why the original design treated the Reception Room as sacrosanct. Even now, some people are still critical of this solution: they think the Reception Room has been demoted: no longer a destination, but just a through-way. It’s a fundamental change in the character of the place.The renovation of the original historic building and the placing of the new building not quite adjoining – because they are two separate buildings – have been done with great affection and respect. And the way through between the two is now in the best possible place, I have to give them that.”

BvS: “The nice thing about the old building is that all the galleries were open, without doors, so you could meander from one to the other. Now that the openings have been made in the wall of the Reception Room, that’s become part of the general open plan too. In future it will function both as an exhibition area in its own right and as a meeting place and transit area to the big exhibition space in the new building. The concealed sliding fire doors preserve the open access between the two buildings while cleverly solving the problem of fire safety.”  The parquet flooring in the old Stedelijk

The Reception Room with two entries to the new extension broken through the wall on the left

Installing a velum

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3. The parquetThe issue: the old herringbone parquet, as the architect proposed, or a different flooring? And, if so, what type of wood, what shade and what pattern?

GvT: “I’m to blame. I just wouldn’t hear of reproducing the old herring-bone pattern. It seemed so old-fashioned. It had to be parquet again because a wooden floor is good for the art works and better for the internal climate of the museum. What we’ve got now is timber flooring from the Ukraine, not from France; that was too expensive. But it looks really good and it’s the right shade: not too red and not too yellow. The long lines, both in the old building and in the new extension, create an impres-sion of continuity and greater visual unity.”

AS: “Mels Crouwel also proposed a compromise: not the herringbone pattern but a sort of zigzag effect. He tried to persuade Gijs...”

GvT: “That’s right – one evening at his place over a bottle of wine, but he couldn’t get it past me!”

AS: “We didn’t want it to look too domestic, so in the end we decided on the long lines. And the planks have hammered edges to make the wood look aged. There were also long debates about the colour and whether we wanted the floor white-washed. But a visit to the Beyeler in Basel put paid to that idea. There, the parquet was whitewashed and it was clearly difficult to clean. There was also a marked difference in colour between the areas with most traffic and the areas at the edges. Another option was a hard, smooth (power floated) concrete floor, but in the end you just can’t beat parquet.”

BvS: “I didn’t pay too much attention to the arguments about the floor: the main thing is that the user is happy with it. Where costs are concerned, it doesn’t much matter what wood you use or what pattern you pick. Durability is important, though.”

4. White walls and a flexible lighting system The issue: what basic colour and atmosphere do you give the museum?

GvT: “For us, it wasn’t a matter of principle that the walls had to be white and that the museum must be a ‘white cube’ like in Sandberg’s time. The architect said he’d give it to us white and if we wanted anything else it would cost extra. White’s a good enough basic colour for the museum, so the walls will be white. Anyway, they can always be painted a different colour for any given exhibition, as is often done these days. So we are free to experiment.”

AS: “There was also an argument with the central government Department for the Conservation of Historic Buildings and Sites, who felt that the areas of wall where brickwork was visible should be restored to their original state, complete with the original stencilled decoration, as has been done in the Rijksmuseum. But we said no, the museum had a history [ed.: in the course of which Sandberg had had the walls whitewashed, so establishing the basis for the idea of the museum as a ‘white cube’] and we want it to show. At the end of the day, all the old decorative metalwork in the building has been restored, but then painted white. Where the walls are concerned, we’re trying to restore the familiar ‘Sandberg white’ with its slight tinge of yellow – shade number 9010, to be precise.”

BvS: “As part of the renovation of the old building, the velums (cloths stretched under the ceilings to diffuse the light) were taken down and replaced higher up, to make the galleries look more spacious. That has revealed the rounded coves where the walls meet the ceiling. The splendid light, for which the Stedelijk was renowned, proved to be far too strong by present-day conservation standards. As discussed in the first issue of Building News, a flexible lighting system has now been chosen.”

The wooden floor in the new Stedelijk

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5. The ‘cabinets’ in the old building The issue: on the first floor of the old building, there was a distinctive suite of small exhibition rooms known as ‘cabinets’; the corresponding suite on the ground floor had been converted into a broad passageway with room dividers inserted to produce a zigzag route between them. Should that arran-gement be restored?

AS: “In the famous suite on the first floor, the cabinets were aligned in what’s called an ‘enfilade’, with an uninterrupted view from one end to the other. Each of the rooms had its own window on the Paulus Potterstraat side, placed high up and providing a north light that was ideal for viewing works of art. That corresponded to the nineteenth-century ideal and that’s the way we’ve left it. On the ground floor, Gijs wanted to preserve the zigzag route, so that visitors walking through the suite are always facing walls of exhibits. And then there were the print room cabinets in the mezzanine on either side of the grand staircase. They were constructed in Sandberg’s time and that whole floor has now been removed.”

GvT: “Actually, the first floor cabinets are ideal for showing drawings and photographs. But exhibits of that kind are light-sensitive, so the only change we’re making is to hang semi-transparent textile blinds in the windows to protect them. The curators are very happy with that decision. The ground floor of the old building is to be used for design and painting exhibitions and the zigzag route will work better in that case.”

BvS: “To meet current conserva-tion standards, the internal climate has had to be improved throughout the museum. For that reason, the sloping walls of the upstairs cabinets have been broken out and rebuilt, so that all the pipes and cables could be concealed neatly inside them. That was another issue with the Department for the Conservation of Historic Buildings and Sites. They wanted to know whether the walls were original 

before giving consent for their demolition. Fortunately, somebody came up with a bit of wood from one of them and we could show that that kind of timber wasn’t in use until after the nineteenth century. So the sloping walls of the cabinets clearly weren’t original and we were allowed to demolish them. Now they’ve been reconstructed and all the technical bits and pieces are nicely concealed.”

6. The basement in the new extension The issue: much of the floor area in the new extension is underground. Wasn’t the construction excessively expensive and time-consuming, and isn’t a basement too dark if there’s no daylighting…?

GvT: “The basement is a distinctive feature of the design: it’s what put Benthem Crouwel’s proposal head and shoulders above all the others. Putting so much space under-ground meant that they didn’t have to build all over the Museumplein. It’s true that a basement won’t get much natural light. The largest exhibition space, measuring 1100 square metres, is down there. But with contemporary art, daylight can often actually be a major problem. Think of video art, for instance. To begin with, we planned to pave part of the pedestrian area with glass, so that the gallery would get some natural light from above, but that proved to be too expensive and too hard to maintain. Anyway, it was impossible from the security point of view. Incidentally, the building satisfies a host of conditions and is also, for example, very elegantly positioned on two of the city’s major axes, the sixteenth/ seven-teenth-century axis of Spiegelstraat and the nineteenth-century axis of Paulus Potterstraat.”

AS: “The essential feature of Mels’ design was the relocation of the entrance to the Museumplein and the only way to achieve that was to construct a lot of the building underground. Of course, there are also disad-vantages to a basement: in Amsterdam, it’s not all that easy 

1. Enfilade of cabinets on the first floor

2. Removal of the floor between the print room cabinets on the ground floor

3. Corridor on the ground floor, beside the staircase, now without the mezzanine floor

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to build underground. It’s all gone very well, though, and we’ve had no leakage. Technically, it’s quite a feat – expensive and time-consuming, and not so easy logistically either.”

GvT: “There was a lot of discus-sion, though, about the internal lay-out of the basement; there was this huge exhibition space, smaller galleries, service areas and an area for education. Originally, the print room was also supposed to come down to the basement but people felt it would be a bit isolated, since the basement is otherwise to be used mainly for temporary exhibi-tions. That’s why the drawings and photographs have now gone to the cabinets in the old building, to make them part of the permanent collection over there.”

BvS: “And then there’s the basement of the old building. A large part of it is now occupied by the museum’s climate control, heating and air conditioning systems. The library stacks will be there too, as will various changing rooms and storage areas.”

All in all, there has been close consultation between the different parties throughout the process, with everyone taking the time to thrash out the various problems and differences of opinion. There has also been collaboration with bodies like the municipal district authority. In the end, the long prior history of building plans may have worked in the Stedelijk’s favour; after all, it meant that the munici-pality had already designated the site for this use. This forestalled very many problems, potential protests and delays.Van Tuyl, Sikkema and Van Stratum all agree that decision-making on the many and various aspects of the project, from parquet flooring to escalator, has never been anything but amicable and harmonious.

Digging out the basement of the new extension under water

Basement of the new extension: the escalator is to be installed on the left and the stairs on the right.

Technical services area in the basement of the new extension