Property: In praise of metal windows: Once reviled, these archetypal Deco features are now a valued part of design history. But there are still snags, finds Caroline McGhie

Windows (Charles Hosea)

ONLY when they have lost their threatening freshness are we likely to show architectural innovation and originality a kindness that we never did in their day.

One such unsung hero of the ordinary home, which was disliked when it was first introduced and has suffered image problems ever since, is the classic metal window. It was revolutionary at the time, quite unlike its wooden, sashed predecessor. It appeared to have been laid on its side, in a style more at home on an ocean liner, made of materials that had more in common with factory machinery than cosy domesticity.

Metal windows arrived in the Twenties and Thirties, winding their slim lines round corners of white concrete that curved as it had never done before, giving that sinuous horizontal rhythm to office blocks and factories. They were echoed in the houses of the period, from the very early white block modernist houses built as 'machines for living' to the rows of three-bedroom semis in the 'moderne' style that stretch out through suburbia, wrapping themselves around the ring roads like architectural ivy.

They have served 60 or 70 years already - longer than many wooden windows last - and as they start to deteriorate the argument is now being put forward that it is time to secure their future. Many in former local authority flats have already been removed by home owners who bought under the Right to Buy scheme and then opted for a traditional or individual look.

As for the fragile survivors, the metal (ungalvanised in those days) has started to rust and the glass to crack. English Heritage is concerned enough about their plight to have organised an entire one-day conference on the subject, inviting speakers from manufacturing and conservationist camps.

To many people it comes as a rude surprise that the metal window has any intrinsic value at all. Julian Holder, case worker for the Twentieth Century Society, fights a lone battle with home and factory owners, trying to persuade them of its merits. Occasionally, when matters flare up to public inquiry level, he finds himself giving sermons on the metal window to the Government's inspector.

'There is a very strong popular image of the metal window being synonymous with the manufacturers Crittall in the same way as the vacuum cleaner is synonymous with Hoover,' he said. 'There were, in fact, a large number of companies making them in the Twenties and Thirties, so there is a rich variety. There were some gorgeous bespoke windows made in bronze with wonderful decorative detailing.' Egyptian, classical and geometric motifs were favourites. Liverpool has a particularly vibrant collection in American Beaux Arts office buildings, thanks to the influence of the westward-looking Liverpool School of Architecture.

The Crittall window, however, which remains the staple form of the metal window, has many admirers too. Even more so since the success of the television serialisation of Agatha Christie's Hercule Poirot stories, in which spectacular examples of Thirties architecture almost upstaged the Belgian detective, and the narrowness of the glazing bars definitely outclassed the even thinner plot lines.

'Builders and architects of the time were using concrete in a very inventive way, creating the feeling that the building was a stretched skin of concrete and the windows were stretched too,' said Holder. 'There is so little in the architecture, just the plain white walls and the windows, that the slightest change in them throws the whole thing off balance.'

Holder maintains that it is now perfectly possible to restore old windows by galvanising them, fitting gaskets to seal out the draughts and even backing them with secondary glazing (as opposed to double-glazing, which is not considered acceptable). He takes a dim view of the imitation windows currently available that come with polyester coatings and a promise of better performance. They lack the pocked surface of the original. 'The aim was always to create a machine aesthetic, but in the Thirties the machines were slightly dodgy and so the windows weren't perfect either,' he said.

This indulgence towards the metal window isn't quite so easy for the home owner to adopt. Andrew Seal bought his two-bedroom flat with a balcony and geometric Thirties fireplace in a purpose-built block in Chiswick last year partly because he was so attracted by the windows. But he is now buffeted by draughts, cracked panes and latches which don't close properly. Replacement window pressure-salesmen have persuaded a few residents to succumb, prompting Hounslow council to respond with warning leaflets.

'The windows look great but I really want to change them. The block has attracted a lot of young buyers because they love the style. But it is so windy inside that the gas man decided it didn't need an air vent when he installed the gas fire,' Andrew Seal said.

Hounslow council says its application to have the block listed as a building of special architectural merit has been turned down and, though it discourages replacements, it cannot oppose new windows as long as they are good replicas.

Another case of metal window

fatigue, at Baron's Keep in the Baron's Court conservation area in London, has resulted in the residents splintering into three factions, each aiming for a different standard of repair or replacement. Hammersmith and Fulham has also had its application for this building to be listed turned down. 'But in a couple of decades it will have earned its spurs,' said a spokesman.

Essex County Council, which has long led the way with its design guides, has produced one specially for the residents of Silver End, the showpiece model village built by the Crittall family for the workers who made the windows. It is now in council ownership with conservation area status and an 'article four directive', which imposes stricter controls on change in an area where 20-30 per cent of the houses have transferred into private ownership.

'The Right To Buy was perceived as a threat to the unity and architectural integrity of the village,' said Andrew Butcher, Braintree planning officer. 'People have a hang-up about metal windows because they often suffer from condensation and rust. The problem was with the private owners who immediately tried to tart up their homes.'

So the design guide landed on their doorsteps and, until fashion changes, it will be the best way the council has of preserving this slice of architectural history. 'It was always our hope that fashion would turn. This is a historical timepiece, an interesting experiment of the age, and has to be given special status.'

Crittall, the manufacturer, which has been involved in the high-profile renovation of the Hoover Building in west London and the famous steel curtain-walling of the Boots Building D10 at Beeston, near Nottingham, finds itself caught between the conservationists and the users.

Mark Schlotel, Crittall marketing manager, is in the thick of it. 'English Heritage wants to wrap buildings in polythene bags for eternity,' he said. 'But we have to balance the aesthetics required by conservationists with the client's expectation of a better performance. The technology must keep moving forward.'

Hence the new range that comes double-glazed, weather-stripped, hot-dip galvanised and polyester powder coated. Unlike its predecessors, this window won't become frozen in time. It lends itself to being constantly reinvented.-

(Photograph omitted)