Giovanna Borasi: OFFICE's early projects were framed within the idea of rooms, literally or metaphorically. In recent years there has been a shift of scale in your work, and I'm curious about how you conceptualize this new scale. I have always thought that the Solo House was a turning point between your initial idea of rooms as a design generator and the new territory of larger projects, like the headquarters for the Swiss Radio & Television (RTS) in Lausanne, or the headquarters for the Flemish Radio and T elevision (VRT) in Brussels.

David Van Severen: Indeed, many of our early projects were conceived as a set of rooms, but this also entailed the idea of a perimeter. Then, the question is how big a room can become to still be considered a room. An early example is the Border Garden project. Nominally, this is a room, with walls enclosing a space. But the sheer size of it makes the notion of the room dissolve. This is not a room anymore, it's a field, a garden, with a perimeter that separates it from whatever is around.

The Solo House expanded this idea of the perimeter. It is not just a sequence of rooms, but an inhabited perimeter, which encloses a piece of nature, or a field. Moving on to RTS, we were dealing with a similar set of ideas there, but in a somewhat inverted way. In its essence, this project is a single open plan, which in the competition text we called 'champ continu' [continuous field], and this field was carved out to make 'rooms' or the four boxes that carry it. As a reference, we used a collage by John Baldessari. The white paper on the photograph is a kind of interruption of the visual narrative, but also an obstacle in a geometrical composition, it frames something else.

Kersten Geers: I agree with David. I do not think our practice has fundamentally changed in terms of its obsessions in the last twenty years. But I do think that unavoidably you evolve a bit. In some early projects, making space was perhaps done in a very literal way. Rooms and perimeters were somewhat obvious strategies to organise the space, to create proximity, but also a certain distance, or a threshold. What was probably implicit in our thinking&mdashmaybe less so in the work itself&mdashwas an idea of hierarchy, what you design and what you don't design. This is true for any scale, but when the size, the processes, the clients, the finances, the technology &mdashthe building conditions&mdash are getting more complex, you have to choose. And I think those formal strategies, like defining a perimeter, or a figure, helped us establish hierarchies and approach these recent big buildings in a similar spirit to the early projects. In other words, formalism here has to do with deciding on certain things and letting go of others. Once you accept the inability of architecture to deal with all the forces at stake &mdashnot only building conditions, but life that unfolds within&mdash the form takes on another significance, it withstands what you can't control. This is something we learned more through the bigger scale of projects.

I feel that indeed, in some recent buildings, whether it's RTS or the Office Building in Kortrijk, there's an extreme complexity on one hand, but also an embrace of a simplified take on materiality, for instance. Things can be a little less sophisticated, and still perform well. Also, mechanical systems, machines so to speak, are a large part of these projects. These large buildings endorse an aspect of abstract machinery, and this was not really a topic in the earlier houses. In Solo House, however, it all of a sudden became a topic: how to deal with all these necessary things like water containers, solar panels, and the rest, if you simplify them.