50 Shades of Clay

From the editors

Words and images Jonas Althuis

04 You don't have to look far to find a brick building in the Netherlands, they're almost everywhere. For centuries, the brick has been a constant; governments have risen and fallen, crises have collapsed the economy, society has changed, but bricks remain. The use of brick is one of the reasons that there are so many century-old historic city centres in the Netherlands; bricks are robust. They don't rot, they're not flammable, they barely weaken over time. So how did bricks come to dominate the built environment of the Netherlands? Where do they get their diverse red, brown and yellow tones from? And what does the future of bricks look like?

Brick buildings are so ubiquitous in the Netherlands, that they've become easy to miss; they blend into the built environment of this country like camouflage. This makes it easy to write off bricks as a boring or generic material, something I've caught myself doing throughout my design projects. "What a plain material", I would think, choosing instead for newer and more technologically advanced alternatives. In an effort to change my stubborn thinking, and perhaps atone for my ignorance, I've decided to re-discover bricks; exploring their history, how they're made, and why they're so commonplace in the Netherlands. In search of answers, I spoke with Koen Mulder; a teacher at the faculty that is specialised in building-technology. Regarding his qualifications, Koen's faculty nickname says enough, it's 'Mr. Brick'. It's from him that most of my new-found knowledge about bricks comes from.

The history of bricks

Baking clay is something humankind has been doing for thousands of years to produce things. From pots, jugs or cups, to figurines and statues, to roof tiles, and of course, bricks. In the middle ages, bricks were made where clay was readily available; typically close to where a building would be built, so that transport distance was minimal. In the 16th century and onwards, brick production became more structured and was clustered around the Dutch rivers that contain the most clay; the IJssel, the Waal and the Rijn. The central area of the Netherlands therefore became the most important brick production hub of the country; bricks produced here were even exported to neighbouring countries. Throughout the centuries, the brick industry continued to grow; in the period of 1850 to 1965, more than 107 billion bricks were produced in the Netherlands. The majority of these are still in a building somewhere today.

Brick dominance

Besides the widespread availability of clay for brick production, how did bricks become such a dominant building material in the Netherlands? That has to do with climate. In north west European countries such as Denmark, Great Britain and the Netherlands, the relatively mild sea climate means that it freezes occasionally, even more so historically than nowadays, but it never freezes for long periods of time. This means that the porous bricks in these countries, made of river clay, aren't damaged by frost that can form inside when they get moist from rain or snow, meaning that brick walls can be left exposed. In countries with colder climates, brick walls have to be covered with an extra layer to stop moisture getting in, which is why you see exposed brick façades much less often in such countries. Germany is a good example of this. Of course, local building history and culture have an important role to play in this as well.

Where bricks get their colour

Bricks are made by first drying and then baking clay; the specific process by which this is done dictates the colour and quality. When the clay is still in the ground or riverbed before it is extracted, it can absorb different minerals that affect the colour when baked. Specifically, it's the proportion between iron oxide and lime that has the most significant impact on the final colour of the brick. With more iron oxide, the brick gets a dark brown or red hue; with more lime, the brick becomes yellow. The result of all this is that, as long as they are the same colour, all the bricks in the buildings around you were likely made with clay coming from the same area, which is quite poetic.

The future of bricks

Bricks have an undecided future. They remain a very popular material, but they are not the most sustainable. It costs a great amount of energy to make bricks; they need to be baked at high temperatures for days on end. Besides that, they're heavy and therefore costly to transport. They are typically also laid one by one by a mason, a time consuming process. When a brick building is decommissioned, it's nearly impossible to re-use the bricks. It's not exactly the material of the future, and modern interpretations that have attempted to tackle these problems, such as stone-strips, seem to have lost all of the qualities that we do like about bricks; their robustness, their historic identity, the character and craftsmanship that comes with being hand lain. If it's up to Koen Mulder, we should look at bricks differently; appreciating them for their longevity and identity. We could change the way we design with bricks to be more flexible for future use. The brick walls of our new buildings could be part of the urban fabric, belonging to the public realm rather than to the building. In this way, we could change the 'building' behind this brick wall when necessary, rather than demolishing it in its entirety. The brick wall itself could remain for centuries.

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On the next page; a collage that shows the diversity in colours that bricks can have, compiled digitally from more than 50 photos of brick walls in Schiedam.

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