• Minervalaan part 2: Disassembling the statues

    Restoration
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    The project

    In the previous post I explained how we got involved in this project at the Minervalaan in Amsterdam. We were asked by Roderick Nijenhuis van Caho BV from Dordrecht to take care of the sculptural parts, but before the time came, the old statuettes had to be dismantled first.

    When I gave a quote for this, I was quite optimistic on the one hand, because over 20 years ago I was closely involved with the restoration on the other side of the street, when I was still working at Mooy Sculptors Ltd. On the other hand, I was dreading it a bit as well, because it is just plain hard work to spend days on a small scafollding with a chainsaw.

    Work across the street, 20 years ago

    Around the year 2001 we started on the southeast corner of this intersection dismantling. We then had a diamond chainsaw on gasoline and with a lot of noise I could cut out the statuettes one by one. After a reconstruction phase we would carve the copies in Bentheimer sandstone. This choice was made because the stone is very weatherproof and lends itself to this kind of sculpture. Later there were a few comments about this choice, because sandstone catches dirt from the air and rainwater and will gradually darken, and also because nowhere else in this neighborhood this stone species has been used for sculpture. Usually you hear nothing about whatever was done well.

    "Tuff is not strong enough’

    Photo of reconstructions from 2002
    The damaged portraits of the South East Corner, with the new copies above, dating from 2002

    At that time we were cutting away the sculptures and I noticed that there was very little stone left standing. Would that even be enough to carry that entire building? A bit worried, I called the office about it. ‘No’, said Ton Mooy, "It's impossible that that building would rest on those blocks of tuff. That material is simply not strong enough to hold up an entire building. There has to be a pillar inside it, take a look.’ And yes, after some drilling and carving we found a concrete core inside the tuff blocks. Apparently a hole had been carved through the blocks during construction and concrete rebar had been put in it, after which everything was filled with concrete. This was clearly visible by the rough outline of the concrete pillar, which exactly matched the tuff's interior.

    This time it went differently

    So this time, twenty years later, I went to work in good spirits with my diamond chainsaw. But once I had cut a few slices away, my colleagues started to worry. ‘Hold it for a minute, won't it all come caving in on us?!’ I said they shouldn't worry, because there would be a concrete core in it. But they didn't trust it and drilled a hole. And when after a lot of drilling and searching we still found no concrete, we immediately stopped the sawing.

    My colleague looked pale as a ghost and didn't want to stay under the underpass for a second. It turned out that these four cracked blocks of tuff kept up the entire facade! Before we cut out the sculptures, the blocks had a cross -section of 72 x 77 cms wide, But after that, only a small block of about 30 x 45 cm would be left! We stopped the job, installed supports (steel poles) and the wedged up the building with blocks of wood and wedges. Time for a new plan.

    Stainless steel support props

    Half a year later we came back. The action plan was approved and the extra budget too, and a construction engineer had made calculations. Big stainless steel props were welded and they would keep things together. During cutting out the statuettes, it became clear how much this restoration was needed. Many of the blocks were not only strongly weathered down on the outside, but they came down in three or more pieces. For years there had been unseen cracks throughout the sculptures.

    removing the statuettes on the Minervalaan 30
    The sculpture was cut loose and is being lowered down

    After a few days with the diamond chainsaw we had pallets full of whole sculptures, but also broken pieces, some of which barely looked like a sculpture anymore. It was a sad heap of rubble, while before, it had looked so nice on the facade! The props now kept the facade up, end then I welded the separate corner pieces together.

    Video: Eight sculptures cut away with the concrete chainsaw

    Found the culprit

    Disassembling the sculptures in Minervalaan
    The support anchors were properly secured
    Disassembling the sculptures in Minervalaan
    Only a thin layer of brick covers the pipe

    Especially the right hand corner, with Spring, a Faun and a Man Sowing, was in particularly bad shape. We had already seen that there was a long crack running through the facade from top to bottom. Would that be because of sagging? But we quickly found out that the cause was due to a leaking rainwater downpipe. Apparently the architect hated rainwater downpipes and it seems he thought it would be much nicer if it was hidden inside the brickwork of the facade. But cast iron rain pipes will rust , and especially when they start leaking. And rust simply expands, it can be up to 7x as thick as the original iron.

    Disassembling sculptures from Minervalaan-rusting rainpipe

    It turned out that in most places only a sliver of about 2 cm brick covered this rainpipe. Not enough to protect it against rust. De downpipe had started leaking and the sculpture had become really soaking wet all the time. Just that in itself would be enough for tuff to weather and deteriorate, but if that moisture cannot go because there is a thick layer of paint covering it and especially when frost periods are added, then the consequences are easily guessed. The statues of Spring and Faun came down in pieces, torn and soaked.

    Archiving

    Crumbled statue of the sower
    The sculpture of the sower had suffered severely under the moisture

    Now I had already taken that into account. Experience had taught me that a lot of information could also be lost during dismantling. Simply because those loose crumbs that now look a bit like a face or a hand, immediately will crumble when you touch such a block. It will never get better once you start dismantling or cutting a sculpture free. That is why I had taken a whole series of photos of every statue, from the left, left front, front, front right and from the right, and preferably more. And from the sculptures on the other side of the street, on the North East Corner, I had taken loads of photos as well. We were going to need that during the reconstruction phase. The old statue would be leading in reconstruction, and hopefully, the photo material would provide enough information to be able to add the missing parts well.

    Gallery: Disassembling the eight statues on the northwest corner

    • Disassembling sculptures from Minervalaan-rusting rainpipe

    Read more about the reconstruction phase in The following blog post: Minervalaan part 3

  • Minervalaan Amsterdam, part 1

    background, Restoration
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    We are currently working on a very interesting project at the Minervalaan in Amsterdam: eight weathered tuff statuettes are to be reconstructed and copied in new limestone.

    Building sculptures on the Minervalaan

    Corner sculpture by Jaap Kaas, Michelangelostraat Amsterdam (Photo Daniel van der Ree, 12 november 2020, Wikimedia Commons)

    On the buildings on the Minervalaan, and by the way in the entire neighborhood around this street, a lot of building sculpture can be found. It was usually carved on the spot by a relatively small group of sculptors, including Anton Rädecker, Jaap Kaas and Hildo Krop. The sculptures were all placed there at the time of construction, during the height of the Amsterdam School building style, around the years 1920, 1930. The work was mostly carried out in French limestone (mostly Euville), in German tuff stone, Muschelkalk limestone or sandstone, or in Bavarian granite. Very unfortunate that this philosophy on building is currently hardly ever imitated anymore.

    Ten weathered statues

    Ten sculptures by Jaap Kaas on the Minervalaan, Amsterdam. Photo from the 80s or 90s
    The entire facade rests on these sculptures

    The project that it's all about sits at the four corners of the intersection between the Minervalaan and Gerrit van der Veenlaan. Ten sculptures have been installed at each of these four street corners. They were designed and made by Anton Rädecker and Jaap Kaas. The themes are, for example, aldermen, architects, workers, seasons and Fauns playing music.

    Ten sculptures by Jaap Kaas on the Minervalaan, Amsterdam. Photo from the 80s or 90s
    Four women for 4 seasons, and 4 working men, plus two fauns

    The sculptures were carved in Ettringer and Weiberner tuff, but after a century of weather and wind and especially leaking water drains, the works are in dire need of restoration. Two of them are still good and will be preserved: the Reaper and the Apple Picker (Summer and Autumn).

    Themes

    Spring. This image was rapidly crumbling away: only a few weeks later we found several new flakes at the bottom of the pillar

    We are currently working on the northwest corner. On the corner of number 28/30 are four statues of women who depict the four seasons, four working men who highlight the work in those seasons, and two fauns with a goat and a deer. The women are just standing being graceful and depict the seasons in four stages of life: a maiden with flowers, for Spring, a young woman for Summer, with ears of corn and flowers, a more mature woman for Autumn, with grapes and apples, and an old woman in a cloak, for Winter. On the inside we see the men, working hard: a Man sowing, for Spring, a Man with a sickle, mowing for Summer, a man picking apples for Autumn and a man digging for Winter. Both of the outer sides are covered by a faun as a sign for Nature: a thoughtful Faun with a goat on the left and a pan flute playing Faun with a deer on the right.

    Gallery: The eight sculptures that are to be replaced from the northwest corner

    Jaap Kaas

    Plaster maquette of Spring, in a box

    At the time these eight statues were all made by Jaap Kaas, an Amsterdam sculptor. He is best known for his striking animal portraits of, for example, the baboons in the Artis Zoo. For the project on the Minervalaan, he made a series of designs in clay and then cast plaster models from it. We know this because one of these plaster casts can still be found in Amsterdam School Museum De Dageraad. You can also see quite well that he used to work meticulously from a maquette because on the other side of the street, on the North East Corner, exactly the same sculptures can be found. That was a big help for us during the reconstruction phase!

    He must have taken these plaster casts from his studio to the Minervalaan and then carved the figurines from a scaffolding, on the spot .

    Traces of carving

    state of the sculpture of Winter, just before dismantling. Paint, water damage, peeling skin and crumbling
    The digging man: Winter. in the last 15 years this sculpture has deteriorated very fast. Many loose parts and loss of detail

    I can say that because four statues have been carved on the inside of the underpass and a fraction of the original block is still in place over their heads. During the dismantling it turned out that this vulnerable layer of tuff is only 1 centimeter thick: he could never have carved this in his studio and then installed it without breaking it off. The only reason that such a thin slice has been left above the heads of the working men, is that he carved it on the spot and has adjusted the upper tuff layer to the existing stucco ceiling. Other, smaller, details also indicate carving in situ.

    Tuff

    Sculpture of Winter by Jaap Kaas, on the Minervalaan, Amsterdam
    again the sculpture of Winter, but then 15 years earlier

    The reason that we are involved in this project on the Minervalaan is that these important building sculptures have been exposed to strong weathering for decades. A lot of repair work has been done on them since at least the 1960s and on more recent photos can be seen that a lot of loss of details has occurred even in the last ten years. At the bottom of the pillars we could also notice, during a second visit to the building just a couple of weeks later, that all kinds of new flakes had come loose in those few weeks.

    Patching them up won't help

    The sowing man: Spring. If there had been no identical sculpture on the other side of the street, reconstruction would have become very difficult. Water damage due to a leaking drain

    There have been discussions for a long time about the condition of the sculptures and all kinds of solutions have been put forward. But what it finally comes down to is clear as day: Patching them up is not going to help anymore. With these kinds of tuffstones, the weathered surface is cracking and falls off, and deeper inside the crack formation continues . Now I have to say that in Ettringer tuff this process is more serious than Weiberner tuff, which can handle internal tensions better. If you want to read more about this, I heartily recommend my article about it the weathering of tuff on this blog.

    Preservation of information

    sculptue Spring at Minervalaan, Amsterdam. the decay is clearly visible.
    peeling layers, dense coats of paint and questionable mortar repairs visible on the sculpture of Spring

    The sculptures of the Minervalaan have also been painted quite a few times in the past, including with waterproof latex paint, and also been repaired with a hard cement mortar. So if you'd just patch these kinds of sculptures up a bit, it would really just be a cosmetic approach. The surface layer of the sulpture, with old and new mortar repairs and all, will come down at some point. And then the problem will be even bigger: all the information that could still be traced from the sculpture has now been completely lost. This would make it increasingly difficult in the future to make a well-founded reconstruction of what has been there. And then we haven't even talked about the structural strength of these building blocks. For this reason, it was ultimately decided to replace the sculptures with copies in new stone.

    Read more in Part 2 about this project

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