Casting off

Lasting impression: John Puttick

The refurbishment of Preston Bus Station (Building Design Partnership and Ove Arup and Partners, 1968-69) was the project that really got our practice started.

The refurbishment of Preston Bus Station (Building Design Partnership and Ove Arup and Partners, 1968-69) was the project that really got our practice started.

Everybody knows it a an example of brutalism, but it’s not just uniform concrete – it’s used in a variety of ways.

There are the big columns that hold up the car park above the main bus concourse, which are exposed with rough shale aggregate, and bring a very warm, monumental character to the space.

But then the ribbed concrete decks above are lighter and more defined. The ribs create longer spans with less material and were cast in glass-reinforced plastic shuttering, which was quite innovative. It’s quite different to concrete buildings of the same era because the finish has a smoother, tighter quality.

The part of the building that everybody knows is the facade, with its the curving slab edges. They set up a mini factory to cast it on site, which was possible because of the scale and the number of repeated elements – it’s a very modular building in a way. I heard a story that for a long time during the design stage, the balustrade on the edge of the car park was simply a vertical concrete upstand.

The problem was that this put too much weight on the edge of the slab, so Arup had to eliminate it and instead came up with this curving leaf-like form that was physically lighter and gave a far more delicate appearance. And that became the iconic image of the building for the city.

A lot of recent concrete architecture approaches the material as fundamentally a heavy, sculptural mass, but the leaf-like elements at Preston got me thinking about concrete shell structures, which are all about lightness. I was in Chamonix a couple of years ago and there’s a sports centre in the middle of the town designed by the structural engineer Heinz Isler (with architect Roger Taillibert, 1971). It has this extraordinary shell arching over the swimming pool. It’s really light and very, very beautiful, and it’s the opposite of the concrete-as-mass approach. As we are becoming more conscious about the environmental impact of materials, this very economical way of achieving very large spans could have a lot of significance.

In a similar vein, the Teshima Art Museum (Ryue Nishizawa, 2010) on Japan’s Seto Inland Sea is a building I would love to visit. It’s very pure: a 40m x 60m shell with a single permanent installation of water droplets that coalesce beneath an opening in the structure. Again, it’s not about mass and weight. It’s only 4.3m high, which strikes me as very shallow for a shell of that size. I’d be fascinated to see how it works technically.

John Puttick is director of John Puttick Associates

Photos Gareth Gardner