New Whitechapel Gallery: Modernism's new home

Nikolaus Pevsner described the original Whitechapel as "a wonderfully original and epoch-making building" in a part of London whose social diversity began in the 17th century, when it became the destination for incoming Huguenots, Portuguese, and Spanish Jews. By the end of the 19th century, it was a ghetto for poor East European Jews and Russians.

The library, and the later self-contained gallery, were founded by the philanthropists Samuel and Henrietta Barnett, and became the reactor-core of British Modernism via brilliant locals including David Bomberg, Jacob Epstein, Mark Gertler and the poet Isaac Rosenberg. After the second war, the gallery premiered the works of artists including Jackson Pollock, Mark Rothko, David Hockney, and Gilbert and George.

The reinvention of the Whitechapel is partly a response to demographic changes. There are said to be 10,000 artists living in the borough of Tower Hamlets; half the local population is under 40, and from ethnic minorities; and half of all adults work in the banking and financial services sector. The gallery's international profile helps to generate something like half a billion pounds in contemporary art sales in London annually, and visitors to the new Whitechapel are expected to spend £2.3m locally each year.

The 78 per cent increase in gallery space, with no closures for exhibition set-ups, could make the Whitechapel, led by its articulate and trend-conscious director, Iwona Blazwick, an even more potent force in art.

The appointment of Robbrecht and Daem, supported by the English practice Witherford Watson Mann, guaranteed a series of settings that are both anti-iconic and anti-white-cube.

"Every [gallery] building should not only be an exhibition space, but able to accept art that is very critical of that space," Paul Robbrecht told me. "Art and architecture have a lot in common, but art now has to work in a mass-media situation. So they have to find each other, in what I call unforgettable space.

"There's a tension. At the Whitechapel, it's a walking experience. You become a flâneur. You choose where to walk. And you are alone. It is a positive feeling of loneliness."

It is no surprise that the architects' fusion of the faux-Jacobean library with the original arts and craft architecture of the gallery has not erased the warren-like atmosphere – thank heavens. On the other hand, two superb new self-contained spaces have been created: a quietly elegant archive and reading room, and a penthouse creative studio for children.

Open, Sesame! the opening show by Isa Genzken, takes over the two main original galleries and a connecting space. Her installations are extremely challenging from a curatorial point of view, ranging from architectural arrangements of glass in New Buildings for Berlin, to Street Party, a detritus-clogged dance of death which seems – quite ideally – at war with the Gallery Eight. The seminal work in Gallery Seven, from the British Council collection, ranging from Freud to Gilbert and George, is brilliantly staged. It looks as though art will flourish in these spaces.

But will eating? There is one dreadful failure of taste and architectural typology: the new café, which looks out onto Whitechapel High Street, lacks only the whiff of ammonia and a Greek chorus of enquiries about holiday destinations to transform it into a ladies hair salon in Weybridge. Or is this what Paul Robbrecht really meant when he referred to his vision of "a condensed urban experience"?