Founded in 1575, the University of Leiden is one of the world’s oldest universities. But when it came to creating a new building to house the University’s Board they turned to modular construction and one of the industry’s most modern cladding materials – organic coated Granite® Silky Mat from ArcelorMittal Europe – Flat Products. The finished structure has the appearance of a permanent building, but retains a flexible character which will enable the university to adapt to the modern world.
“The University asked us for a building that would last between 10 and 15 years, but which would blend in with the existing built landscape,” explains Koen Gosens, account manager at De Meeuw – the company charged with designing and building the new offices. “The power of De Meeuw is that we can quickly create such buildings using a modular system.”
De Meeuw typically utilises its own pre-fabricated system for modular construction. However, that system features a corrugated appearance. “That would not have fitted with the University’s environment,” notes Koen Gosens. “Our R&D department had a copy of the Steel Envelope design guide from ArcelorMittal, and there we found a sample of Granite® Silky Mat. I suggested it to the customer and they were immediately excited. Granite® Silky Mat fulfilled both their quality and aesthetic expectations. The Anthracite colour was also a perfect fit with the adjacent buildings.”
Detail of the Granite® Silky Mat surface showing the rough texture
Although Granite® Silky Mat has a slightly textured surface, it looks very flat from as little as five-metres away. Compared to other facade materials, the Granite® Silky Mat panels can be relatively thin, notes Guus Hoogland, sales manager for Bijlbouw – the company De Meeuw asked to create the facade: “The panels we used were just 1.5 mm thick. To achieve the required flatness in aluminium we would have needed a thickness of around 2.5 mm. I was also very happy with the price comparison – we saved around 20 percent compared to aluminium.”
Another key advantage of steel was strength. “Steel is stronger,” says Guus Hoogland. “The inherent strength of steel enabled us to specify wider and longer panels – the average was 500 by 3,500 millimetres. The cassettes were 1,200 by 1,500 mm – that’s very large. To achieve these sizes in a material such as aluminium we would have needed material 3 mm thick.”
From as little as five-metres away, Granite® Silky Mat appears perfectly flat
Bijlbouw contacted ArcelorMittal Construction to create the facade elements, notes Guus Hoogland: “ArcelorMittal’s Tiel factory is very well-equipped so we asked them to manufacture the panels and cassettes. We have worked with them for many years. It was a big advantage to have a single supplier we knew we could rely on.”
Levi Kleinjan, ArcelorMittal Tiel’s project adviser for special facade systems examined the plans and talked the Bijlbouw engineers through some of the technical constraints of working with Granite® Silky Mat: “That resulted in a few very minor engineering changes to the design. We then ordered 1,500-mm wide coils so we could achieve the very wide panels and cassettes.”
Thanks to the use of pre-painted steel, it was possible to make very large panels and cassettes
The finished facade elements were delivered to the Leiden University site where they were mounted by the Bijlbouw team. “The result is a fantastic looking building which is in keeping with its surroundings,” says Koen Gosens. “The customer is very happy with the result.”
Steel Envelope is a book and website developed specifically for architects and designers. It contains samples and technical details of ArcelorMittal Europe – Flat Products’ portfolio of aesthetic steels for construction applications.
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Copyright images: Lesli Taihuttu