Youthful exuberance

Architectural Review, The, August, 1994 by Peter Blundell Jones

Peter Hubner has become well known in Germany, particularly in the Stuttgart region, for his radical participatory work, which started with a student hostel and continued with a series of youthclubs and schools (ARs June 1985, March 1987, September 1990, and March 1992).(1)

Not only has his collaborative, improvisatory method proved a pragmatic and extremely economical way of producing buildings, it also helps to generate and bind together a committed community of users, which continues even after the original self-builders have left.

So, when revisiting the projects of the 1980s, one finds not only that they are still operational and in good condition, but also that they have grown and changed. Hubner, asked when one of his buildings would be finished, once replied: 'Never, I hope.' More than any other architect I know he takes seriously what Giancarlo De Carlo called the third phase of the planning process: that of use and evaluation. The building is not a static technical entity or a self-contained work of art but remains in living dialogue with its users.(2)

Following his successful youth clubs at Stuttgart-Wangen, Herrenberg and Stammheim, Hubner was approached by the Stuttgart Youth Club Society to see whether something might be done at Feuerbach, a northern suburb close to Stammheim. The suggested site was in a narrow valley just outside the residential area, on a piece of ground owned by the city where a rain-water storage tank had recently been built. This enormous structure, some 36m in diameter and 5m deep, has a capacity of about a million gallons. It is not a reservoir, but a holding tank for storm drains, absorbing flashfloods produced by sudden downpours and then releasing the water slowly. Built as a purely technical installation and buried in the ground, it has no external identity and gave no clue of its dramatic purpose. From the start, though, Hubner saw it as a feature ripe for exploitation, and although the city engineers were initially adamant that there should be no building on top of it, they eventually relented.

As with earlier schemes, Hubner organised brainstorming sessions with the local youth to gather their suggestions for the club, and arrived at the concept of a Wasserschneckenschloss (water-snail-castle), an elaborate spiral structure including a solarenergy strategy. Excluded at this stage from the rain-tank's territory, it was to stand to the east, the side closest to the town, surrounded by its own moat in representation not only of the castle fantasy but also of the water below. In the mean time the mayor's office had been considering the accommodation of ever more numerous summer backpackers who were overpopulating the youth hostels. They were impressed by the arrangements in Munich, where since the Olympics of 1972 a large beer tent has been made available. For a tiny fee travelling students can have a safe shelter in which to lay out their sleeping-bags, buy a cheap meal and take a shower. The land in Feuerbach offered a good site for a Stuttgart version, for though a long way from the centre, it stands directly by a tram-stop. A tent was initially proposed on the open ground just beyond the proposed youth club and the rain-tank, and it was suggested that the backpackers might share services with the youth club.

Hubner thought that the whole thing could be more integrated and more permanent. For summer use, the accommodation did not have to be to a high environmental standard or quality of finish, and so could be accomplished relatively cheaply. The social and service facilities would serve the youth club for the remainder of the year, so would need to be closely geared to both uses. Then there was the rain-tank: its dull technical presence made a good piece of land sterile, but it could become an asset. Its heavy construction could serve as a foundation for the summer camp buildings, saving enormously on groundworks. These economies understood, the engineers were persuaded that the perimeter wall of the tank might be used, but its southern quarter was to be left clear for access. Eventually they agreed to allow light construction over the central area of the tank, provided that the loads followed its nine metre structural grid.

The main loads needed to be taken by the single perimeter wall, so were best cantilevered equally to either side. The timber struts would need to be clear of the wet ground, so it was easiest to raise the whole accommodation a storey and place it on top of the perimeter wall, which could then also be the enclosing element. So arose the concept of the Haus auf der Mauer, like the wall-houses on the edge of medieval cities. The three metre high concrete wall had to be specially built, but it precisely follows -- and reflects -- the tank structure beneath. The city wall encloses an outdoor room, the market place, concentrator of social exchanges.

Around the inside of the wall at ground level are service rooms and offices, while in the middle of the west side exposed to the morning sun is a cafe. This part of the building protrudes the most into the communal open space, and its straight front follows the structure of the water tank beneath. The curious and attractive curved eaves are the result of the conical roof being cut off in a straight line.