The ultimate accolade of World Building of the Year has been scooped by Grafton Architects for a major building in Italy, writes Frank McDonald

GRAFTON ARCHITECTS, headed by Yvonne Farrell and Shelley McNamara, surprised and delighted most of their peers in 2002 when they won the competition to design a new building for Bocconi University in Milan. That a relatively small Irish practice could win such a plum job was - and still is - seen as a remarkable achievement.

Six years on, the massive new building, occupying the length of a city block is now complete and will be officially opened tomorrow in the presence of the Italian president, Giorgio Napolitano, and European Commission president, José Manuel Barroso, after mass celebrated by the Archbishop of Milan, Cardinal Dionigi Tettamanzi.

It has been hailed by Domus, Italy's leading architecture journal, as a "an extremely powerful composition ... a great constructivist sculpture [that] stands out against the featureless housing blocks and tenements" in and around the Via Bligny and Via Roetgen, giving the gritty city of Milan a new "urban monument".

Casabellawas equally enthusiastic. "Those who see it immediately realise that this is an erudite work of architecture, with roots in the tradition of the Modern Movement. The long architectural history of the Bocconi University ... could not have met with more appropriate, significant results than this major work."

A year ago, when Farrell and McNamara gave a talk on their magnum opus to the Société Française des Architectes, they got a standing ovation - an extremely rare response to visiting architects in Paris. But this accolade was confirmed last June when some 30 members of the society went to see the building.

After the group was given a guided tour by McNamara, I asked Laurent Valentine, the French society's president, what he thought of it and was quite startled by his reply; he didn't hesitate in describing it as "the most significant new building of the 21st century". Anywhere? "Yes, anywhere", he replied, matter-of-factly.

Valentine's view was confirmed last weekend when Grafton Architects not only won the World Architecture Festival's award for buildings in the education category, but scooped the World Building of the Year award for Bocconi in a unanimous decision by the jury for its effortless 3D design and the way it knits into the fabric of Milan.

Yet it arose from a stroke of luck. Early in 2001, Farrell and McNamara gave a lecture on their work to staff and students at Mendrisio School of Architecture in Ticino, the Italian-speaking area of Switzerland. Kenneth Frampton happened to be teaching there at the time, and he was also advising Bocconi University on its project.

So when a shortlist of 10 architects came to be drawn up, Grafton was one of them; the rest came from Italy, France, Spain, Switzerland and Norway. "We put our heart and soul into it because it was a real chance for us," McNamara recalls. "It was a bit like athletes testing their fitness, because you have to run like hell."

They had to make a proposal for a new building of 45,000sq m (484,380sq ft) to house conference facilities for 1,500 people and offices for 1,000 professori on a restricted site of less than half an acre - for a prestigious institution, founded in 1902, that is regarded as Italy's equivalent of the Harvard Business School. "The interview was extraordinary," says McNamara. "There were 40 people around the table, including a bishop and the board of the university. Yvonne was explaining that the structure of our building hangs from the roof, and this was met by disbelief. So she went round and explained it to them, using the model we built."

What complicated matters was that neither of them spoke Italian and had to rely on simultaneous translation. But the university and its advisers, including Frampton and Henry Ciriani, were convinced that this €85 million project could be entrusted to the pair and they got a call to tell them they had won.

"We went back to Milan the following Monday for a press conference, then had to start work immediately after agreeing terms," McNamara recalls. "We had to appoint consultants, become familiar with the legal and contractual situation in Italy, and then we had to produce all the drawings and documents in 10 months - in Italian."

Bocconi's director of buildings, Nicola di Blasi, "directed everything and found the right people for the team - all Italian, except Klaus Bode, an environmental engineer based in London". He also travelled to Dublin to see some of Grafton Architects' recent work and was amazed by the small scale of most of it, but "went back happy".

Every two weeks, Farrell and McNamara used to get up at 5am for the 7.10am Aer Lingus flight to Milan, where they were picked up at Linate airport and taken "straight to our desks where we worked all day and went out to have dinner in the evenings". Bocconi's team also visited Dublin every few months to discuss progress. The challenge was formidable. "The effort that goes into building something of that size is enormous and hugely challenging. But the amazing thing is that we were ready for it. And it's wonderful to get a project of that scope; it changed our work, the whole way we think about things."

What the result shows is that even small architectural practices are capable of producing big buildings. "We were also working in a different country, where the engineering skills are extraordinary as well as the sense of style. The question they kept asking was 'is it beautiful enough - is it as beautiful as you can make it?'."

When Grafton decided to clad the building in speckled grey Ceppo stone from a quarry near Milan, the university bought the hill it came from to be sure there would be enough.

Although the cladding is only 30mm thick, it gives the building a monolithic appearance, as if the quarry had come to Milan. The stone continues seamlessly into the interior, where concourses are floored in gleaming white Bianco Lasa marble, "like inside an oyster shell", to reflect light drawn in by a 40-metre glazed curtain wall.

Planning regulations meant that the building could not rise higher than 22m from street level, so the university's Aula Magna and five lecture theatres had to be put underground. "The biggest challenge was to make a below-ground space that was habitable and pleasurable," McNamara says. This meant making a huge hole in the ground, 23m deep, and it took a full year to do the enabling works.

At the corner of noisy Via Bligny, which is on a tram route, the architects pulled back the building at ground level to create a public space on the corner - with the huge window "like a big mouth, to let the city flow through it".

Above ground, the architects had the idea of making "a labyrinth of buildings" with an east-west orientation and internal courtyards to draw in natural light. Offices are clad in "glass shingles", slightly overlapping, while the corridors have glass walls and doors - all on a 170x70m site that used to be a bus park.

But there's as much underground as overground. The Aula Magna is bigger than the Abbey Theatre, with a capacity of 1,000. Fitted out by Italian architects in what McNamara describes as a "very Milanese" style, it will be used for conferences and recitals. The space beneath the car-park ramp is so big that it can house exhibitions.

The building, with spans of 25m between its structural supports, is a 3D tour de force that's bound to win more accolades for Grafton. Not only do McNamara and Farrell now have a working knowledge of Italian, they've left Milan with un nuovo simbolo di pietra e cristallo - a new landmark of stone and glass.