Architecture: Even in Bath the millennium builds a head of steam

A brilliant scheme for a new bath house should not only restore Britain's most famous spa but also, says Nonie Niesewand, provide a modern building worthy of its setting.

Bath is to have a new bath-house if the Millennium Commission gives its council pounds 6.5m to develop the blue-plaque city as a spa town again.

Bath has Britain's only naturally occurring hot springs and the architect Nicholas Grimshaw has designed a building that uses the heat from the hot springs to heat it, as well asthe pools and a Bath stone building behind a glass facade. Steaming away like its inhabitants, this facade will look like the opening to Phantom of the Opera with dry ice swirling in mists.

Hundreds of fine glass pipes sandwiched in the glass facade will carry thermal water from the earth's core to heat the building in winter and with venting, cool it in summer. The way he has used water and steam as an integral part of the building illustrates Grimshaw's eco-tech approach to architecture. In the scorching summer of 1992 in Sevile he made the British pavilion the coolest glass box with a fountain down the facade.

"It's a great opportunity to reunite Bath with its waters," said the architect, who proposes to connect the new Spa complex to the Roman baths with a wonder wall of steam from the end of Bath Street along the centre of the colonnaded Bath Street to terminate at the Cross Bath, restored as a working spa.

The wonder wall will link four historic listed buildings, the Cross Bath, the Hot Bath, the Pump Room and No7 Bath Street. And to build the new spa the Beau Street baths will be knocked down. An historic building in a World Heritage site, these municipal baths, built in the 1920s are no great loss. They have an acceptable stone elevation with a pediment at Beau Street, but ugly angled steel trusses, roof lined with asbestos. Besides, they had become rather "seedy" as Paul Simon, project manager for the Bath council, described them.

"Bath is renowned as a city of wonderful architecture but there's not one decent example of 20th-century architecture. This building by Grimshaw will be our last opporutnity."

Using water and light, glass and stone, the new Spa building will offer treatment rooms, hot baths and jacuzzis, as well as three swimming pools, available at special discounted rates for local residents. Sensitive to its historic site, proportions of the new building totally mirror the square plan and inner sanctum of the John Wood's Hot Bath, built in 1787. Paul Simon says that more than 300,000 Britons visit spas in Europe each year. So Bath council is determined to use its greatest natural resource, the million and a quarter litres of water arriving daily in three springs at a temperature of 43C to 47C . The heat of the water in the spa will take care of all the energy needs. The pungent, sulphuric natural water will have the iron and sulphur filtered out, by a process which uses no chemicals,to stop it staining the limestone orange, not because bathers mind holding their noses when taking the plunge.

Spas have fallen from fashion so much that some spa towns capped off their natural resource. Leamington built a library over its spa, and Buxton a shopping centre. Bath's spa town image had fallen from its Jane Austen fashionability and patronage from royalty. Now the other spa towns are getting steamed up over this millennium bid: Buxton, Cheltenham and Harrogate have written letters of support. Clearly the venture, if it is succesful, could set a trend. But when does a spa become a health hydro, or worse a leisure centre? Bath council which will lease for 25 years the operation of the spa to a Dutch company called Thermolyae, is keen to promote the healing powers of taking the waters, along with aromatherapy, massage and watsu - the shiatsu method of working out in water.

"Leisure centre, yes, but waterworld with wave machines and so on, definitely not," Mr Simon said.

"No shrieking and yelling. More like flotation tanks in the knowledge that waters helps stresses, backs, skin ailments.''

So how do you prevent it getting like Lourdes?

"Cross Bath is the sacred pagan shrine of the Celts, one that the Romans dedicated, and there are those - myself included - who believe that it is a spiritual place within the space. At present it is enclosed by a semi-derelict Georgian stone wall and glimpsed through a metal grille in the wall. It is atmospheric and moving. That will be left for people to make the pilgrimage to those waters,'' Mr Simon said. Then there are rooms for serious medical treatment, from straightforward physiotherapy to acupuncture and hydrotherapy.

Throughout the research of the project, Bath council involved a disabled access lobby group in Bath which was given a grant separately to pay for its own architectural consultant to advise on the lifts, ramps and hydraulic platforms for pool areas. And Mr Simon hiked across France and Germany, Spain and Hungary to discover just why Continental employees build into workers' contracts sabbaticals at a health hydro every few years.

Unlike so many projects tumbling from the drawing boards of architects around the country to get the last lottery money from the Millennium Commission, this project has been ingeniously worked through both in style and content. As the Ove Arup engineer Alistair Guthrie says "Nick Grimshaw has made a real effort to integrate new technology and new ideas within the context of Bath.There is a certain sense of old set against the new - Bath stone buildings against the glass buildings flow from one to the other". Equally important, Bath Spa addresses the way in which all these Millennium-funded projects will be judged in the next century - by projected attendance figures.

Bath is already the fourth biggest tourist attraction in Britain, after London, Edinburgh, and York. The council is determined to make the most of this position with the 18th-century, small and intimate spaces enhanced by the big bold Grimshaw complex that will run as a viable commercial venture. In order to qualify for Millennium Commission funding, a scheme must look back over the last two millennia and forward to the new one.