Architect's house.

In an act of unusual bravery, Danish architects have put their savings into an ingenious building which is rented by the architectural institutions and the Foreign Office.

Tre Gang Nielsen is one of the most impressive practices in Denmark and it has recently burst out of its relative obscurity in provincial Jutland to start conquering the capital. Tre gang (three times) Nielsen is no longer an accurate description of the firm, for one of the original Nielsen partners has gone off to be a professor, but the remaining two keep up the jaunty (yet serious} nature of the firm that its title implies. The outfit won the national competition to build the Danish architects' headquarters in 1994, and as these pictures show with great honesty, the building is not quite finished yet, and its surroundings are nowhere near completion. It is an impressive act of faith in the future and in the powers of contemporary designers by the Danish architect's federation (DAL), which has sunk much of its pension fund into the building - a brave move for a professional institution which has had no parallels in vision or investment since the Royal Institute of British Architects made its home in Portland Place 60 years ago.

The site is absolutely outstanding. It looks over to the centre of Copenhagen across the harbour, the strip of sea that gives the city its raison d'etre, at its narrowest point. The south part of Christianshavn (the area not occupied by the Navy - p50) is a wonderful piece of city with a mixture of domestically scaled buildings and warehouses, which vary in splendour from the Asiatisk Kompagni's eighteenth-century Baroque palaces to the huge and styleless Gammel Dok (Old Dock) building, a rugged utilitarian structure in yellow brick under a vast pitched roof of red pantiles. The Kompagni's buildings are now the headquarters of the Danish Foreign Office. The Gammel Dok houses the Architecture and 'Building Export Centre and 'the national workshops for the visual arts' - studios for artists honoured by the state.

Between the two huge buildings was an old dock, filled in 1918, so creating a virtual urban space that has never until now been properly used. The architects' building completes the space, making a front onto Strandgade (Shore Street) the road onto which the Asiatisk Kompagni faces, and at the same time, it makes a square with an open side overlooking the harbour.

There is a fashion in Scandinavia for buildings with a gulch in the middle (think for instance of the Finnish Embassy in Washington - AR October 1994, or that country's Seville Expo pavilion - AR June 1992). Here in Copenhagen, there is a very good reason for the parti. The upper floors are occupied by completely different organisations.

On the street side, the Foreign Office has three floors wrapped in white stucco with holes punched into the walls in a conventional way behind a veil of timber louvres on a steel frame. These floors are connected to the ministry's main buildings by bridges and do not link with the rest of the building apart from in fire escapes and a few spy-hole windows that peep out into the gulch.

The rest of the building is given over to the architects, with meeting and exhibition rooms on the ground floor, and the offices of the institute, the main associations (of employed and employee architects) and the splendid Arkitektens Forlag (The Danish Architectural Press)(1) stacked up in a slab that faces the new square. The slab is a box within a box: the outer one is of steel and glass in the Danish tradition (p34), very smooth, but with opening lights for each office. The inner one is apparently of wood, for each office has a wall of floor-to-ceiling maple veneered vertical louvres(2) which can be manoeuvred to suit the view and lighting requirements. The combination is an obvious reference to Dominique Perrault's Tres Grande Bibliotheque in Paris, but, whereas there the wooden-box-within-the-glass was adopted as a desperate expedient to prevent the books being cooked by the sun in their sealed glass towers, the Copenhagen building uses the combination to make a layered external skin which allows individual inhabitants to make their own choices about ventilation and lighting of their workplaces (and in so doing animate the building in an ever-changing and subtle way).

Between the two slabs of offices is the gulch, dramatically lit from the top as the glass skin of the office is pulled back over the roof. Here, the stairs to the architectural floors make a gigantic, slightly skewed steel sculpture that dominates the whole space and provides an honorific progression towards the light. The back of the Foreign Office floors is covered in the same white stucco as its outside, reflecting luminance into the volume, and the steel landings of the architects' floors opposite. These are arranged in enfilade with minimal glass partitions between the different functions.

The ground floor of the huge space is perhaps rather darker than it should be, because the stair structure blocks out much light from the roof. But there is a cross axis from the entrance towards the harbour, which is emphasised by cutting away the floor in a series of giant steps that echo the form of the old dock and face the glass wall (this time with no timber veil). It is rather difficult to see what this move offers (except for light), for though it could be a sort of lecture space, there is not much room for a lecturer in front of the glass wall. Yet perhaps it is too early to judge. The new square is nowhere near finished. It is to have an abstracted reflecting pool which will evoke the old dock, and water will pour down the wall facing the big stairs: we shall see whether the result compensates for the apparent lack of function. Elsewhere, the ground floor is walled with huge stainless-steel finished partitions which are pivoted to become display screens when the meeting rooms to the left of the entrance are thrown open, as an exhibition area. As yet it is too early to see how these arrangements will work, but certainly the device of swivelling walls lets light into the otherwise slightly gloomy ground floor and should offer many alternative configurations of the spaces.

If I have been a little adversely critical of the building, that is because it is daring, and tries to do so many things at the same time: re-establish the street and create an urban square; evoke memory of the long-forgotten dock; accommodate two very different clients and re-define the nature of a professional institution. It succeeds admirably in most of these respects: that it does not work totally in every way is not surprising. But this review is written when it is clear that there is still time to fine-tune the whole affair.

1 Probably the only independent architectural publisher left in the world. It produces books (and magazines) of very high standard, see for instance p89.

2 Their internal structure is aluminium.