The temporary pavilion on the grass in front of the Serpentine Gallery is an architecture exhibition of the 1:1 variety. It’s no representation in the form of drawings or models but a real building in which the architect’s intentions can be experienced in reality. Each year the Serpentine Gallery invites an architect of stature. Unites them is the fact that the pavilion is their first completed building in Great Britain. After Zaha Hadid (2000), Daniel Libeskind (2001), Toyo Ito (2002), Oscar Niemeyer (2003), MVRDV (2004 not built) and Álvaro Siza (2005), it was the turn of Rem Koolhaas this year. 

Koolhaas and Cecil Balmond worked closely during not only the construction but also the design process. The design is even based on drawings Balmond had already made for a competition in which he proposed a building roof in the form of a balloon that floats away in fine weather. The finished pavilion is a ‘non-pavilion’, according to the Arup press release, ‘built using “non-structure”, defying the force of gravity’. ‘With its combination of pioneering design and engineering innovation, the Pavilion is a unique achievement and promises to be unforgettable,’ the press release proudly claims.

The seemingly weightless pavilion is made of a circular platform of galvanised plates that support a drum of polycarbonate sheets on which a helium-filled egg-shaped balloon floats. Five metres high and 30 metres in diameter, the drum is kept rigid by four beams – each as heavy as a new Mini Cooper. The drum is enclosed by double walls that conceal the beams and create a cavity that contains a bar and other functions. The introvert, public central space is dominated by heavy cubes of different sizes that are seats, not artworks. 

Floating above the drum is the balloon filled with helium and air. Ropes and cables ensure the balloon doesn’t float away. In good weather the balloon can, in theory, rise by 4 metres. That will be an imposing sight. But just how good does the weather have to be? On a tropical Friday afternoon the balloon had lifted by no more than a metre. Not exactly impressive, but it did at least provide for some ventilation and fresh air. 

The egg-like shape is achieved because the balloon presses on an aluminium frame that measures 10 by 10 metres. Attached to the aluminium frame is a work by Thomas Demand: a wallpaper that depicts ivy. It looks like a photo-print but that is a false impression. From close by the picture is in fact abstract and artificial, according to the Serpentine Gallery. Just one small problem: Demand’s work floats metres clear of the ground.

The art in the pavilion is of minor importance. So, too, is the context (Kensington Gardens in London) in which the pavilion is located. It could be anywhere. And the architecture, too, seems of minor importance. The structural detailing may have given Balmond a few headaches, but spatially the pavilion offers no surprises. But that’s not important. Koolhaas: ‘The 2006 Serpentine Pavilion will be defined by events and activities. We are proposing a space that acts as background for conversations and a container of informalism.’

The big event was a 24-hour interview marathon that took place on July 28 and 29. Koolhaas and Hans Ulrich Obrist received around 60 creatives in their cocoon: artists, architects, writers, fashion designers, directors. In friendly conversations that lasted 20 minutes the interviewees were asked about the role played by the city of London in their work (all this interpreted very broadly) and what their dream project or utopia would be.

The next event was scheduled for August 11: Motiroti Priceless Launch, a ‘cutting edge multi media presentation’. This will be followed a week later with a presentation by Thomas Demand, Olafur Eliasson and Beatriz Colomina. In the meantime it’s up to the visitors to make their own events. In the pavilion they can buy food and drink, or they can shelter there when it rains.

As Arup has promised, the pavilion by Koolhaas and Balmond is indeed unforgettable and so light it is almost unbearable.