Inner space

"Mather's Ashmolean redevelopment is a timely reminder of the importance of articulated space as an essential medium of architectural expression."

Felix Mara

As I approach the Ashmolean Museum of Art and Archaeology in Oxford, I don't notice that the facades of Charles Robert Cockerell's 1845 makeover of the museum have been cleaned. When are they going to replace those tattered pennants? But there is evidence of activity: the lofty doors of the main entrance have been renovated and opened, revealing a new, impossibly tall, glass revolving door.

I am all anticipation as a classics graduate who once mounted a print collection here. Along with Antiquities, the museum houses departments of Eastern art, Western art, coins, conservation and sculptures. At its opening in 1683 the Ashmolean was England's first public museum. It is an extraordinary resource. Part of the University of Oxford, it enjoys a certain autonomy but it is open to the public, for free.

Once inside I am greeted by the architect of the makeover, Rick Mather, and the Ashmolean's director, Christopher Brown, who exudes boyish enthusiasm. Clearly very excited, he explains that on Saturday the museum will re-open to the public, marking a key stage in a redevelopment programme that started in 1999. Its objectives were to enable the museum to exhibit more works and to improve organisation, circulation and performance. The redevelopment has 100 per cent more display space, with 35 new galleries, four temporary exhibition spaces, three new study centres, an education centre and a restaurant.

The principal existing building, by Cockerell, has been refurbished and remained open until last Christmas, but Mather persuaded the planners to permit demolition of the 19th-century extension in 2006.

Brown explains the client's display strategy, Crossing Cultures Crossing Time, which seeks to blur the territorial boundaries between departments. The main feature of this strategy is a chronological sequence of displays from the ancient world at ground-floor level to the modern world on the first-floor. Mather says the spatial strategy was developed, using physical models, to form an interlocking puzzle with a remarkable logic.

'The only two ground-floor openings from Cockerell's building to the new extension are on axes created by the portico and the west pavilion. These are carried through into the new building as major routes, defined by double-height galleries linking across the back to form a "U"-shaped configuration, which in turn lead into new open, single-height galleries. When visitors enter or leave these lower galleries they find themselves in a double-height space, making it easy to find their way around.' Mather points out the glazed steel bridges, only 150mm deep. From these bridges visitors can glimpse the other galleries and views up and down to other parts of the museum, physically crossing cultures, crossing times'.

The services strategy and detailed design reinforce this arrangement and the needs of the displays. The ventilation system is routed through risers in the gallery walls, rather than through the ceilings, maximising the heights of the spaces, which are constrained by planning restrictions on the building height. Stephen Greenberg of exhibition designer Metaphor adds: 'We decided to integrate as many showcases as possible into the deep walls. The result looks effortless but was technically hugely challenging.'

Returning to the main staircase Mather explains an ingenious device. 'At the corners of the "U" we have positioned two public staircases. The first steps up through six floors to a rooflight. The second steps up to a huge window looking towards St John Street. Natural light is brought down to the lowest level through these spaces. These "landmarks" on the major routes make the building easy for the public to understand and use.'

The rooflight above is elegant but the staircase itself appears overwrought. Their stepped soffits look awkward where they are curved on plan and the tapering, curved glass balustrades are marred by handrails which have been bolted to them. It is understandable that Mather has allowed himself this one indulgence in such a mature design: with self-effacing decorum he has concentrated on the essential spatial and operational requirements of the museum. Like John Soane, whose picture gallery in Dulwich, London, Mather extended in 2000, he is an architect who enjoys grappling with internal space.

In recent years many architects have concentrated on producing sculptural object buildings, with the emphasis on external volumes or interiors; most are like vast well-appointed hangars. Mather's Ashmolean redevelopment is a timely reminder of the importance of articulated space as an essential medium of architectural expression. At the end of our tour I remark that it's amazing that the design provides such quality of space and doubles the floor plates' size. 'It's because we had such a good architect,' says Brown. Mather remains silent.

Felix Mara