A PHILOSOPHY SET IN CONCRETE

"IT'S NOT exactly a thing of beauty, is it?" muttered one woman as we joined a group of sightseers gathered on the lawn in front of the Concrete House in Bristol. A pale wash of autumn sunlight flattered the white rendered surfaces of Amyas Connell's 1930s creation, but she remained unmoved. The flat-roofed houses of the Modern Movement's brief inter-war flowering have never found many fans among the British. Concrete is not our favourite building medium, either. None the less, an invitation to step inside proved irresistible - like going to the zoo to see some rare and baffling non-indigenous beast.

We paused at the entrance to take in the curve of pre-cast concrete that sits over the porch; looked up at the rectangular tower of glass that houses the stairwell - a trademark of Connell and his partners, Basil Ward and Colin Lucas. The house, explained our guide, was a fine example of the International Style, brought from Europe by a trickle of emigre architects who inspired experiments with new materials and radical Bauhaus ideas. Some of the group's eyes glazed over as he made his fourth reference to "sculptural forms". Never mind that, let's get inside for a nose round Mrs Stevenson's home furnishings.

It was Doors Open Day in Bristol. The Concrete House - a Grade II* listed building designed by Connell, Ward and Lucas in 1934 for the tobacco industry executive Ronald Gunn - was the only private house offered among a range of properties unlocked for a one-day tour of inspection under the scheme organised by the Civic Trust and National Heritage. The present owners, Alan and Vanessa Stevenson, had gamely agreed to open the ground floor of their suburban house because they "wanted to encourage a wider appreciation of this style of architecture".

They accept that a stark concrete cube is not everyone's ideal home, but these houses were designed to be enjoyed from the inside looking out. Modernism was all about pristine surfaces and clean, uncluttered space - functional, flexible and flooded with natural light. The Concrete House is a family home, not a shrine, but the Stevensons have carefully preserved a sense of the period.

In response to their open-house invitation, they reckoned on 100 visitors. On the day, however, more than 1,000 people trooped through their open- plan lounge-diner, admiring original chromed door handles, Connell-designed built-in furniture and an early example of an integrated sound system, which still works. The Stevensons were overwhelmed, not so much by the volume of traffic but by the warm, enthusiastic response of the majority. "Oh, I could definitely live here," said one enthralled visitor as the sun shone dutifully through a wall of picture windows. Even some of the sceptics emerged as converts.

"The younger generation seemed particularly enamoured with the house," says Alan. "We had groups of students eulogising over the Modern Movement all afternoon. One young man told us he was completely knocked out by the interior." For the Stevensons this represents a welcome change in attitude, a sign perhaps that the much-maligned Inter-national Style is at last beginning to establish a popular following here. "Ever since we moved in, people have been endlessly critical about the house," says Vanessa. "Sometimes we find it very hurtful because they are implying we have bad taste."

Even a building society poured scorn on the Concrete House when the couple applied to mortgage the property in the early 1970s. "They said the style of architecture was more suited to an airport building than a residence," says Alan. "They also compared it to a public swimming pool. It was obvious that we were refused a loan just because the lender didn't like the look of the house."

They got their mortgage in the end, but a Nineties' borrower seeking a loan to buy the Concrete House, or one of its lookalike contemporaries, might meet the same level of resistance - though for different reasons. For one, the prevalent use of concrete and steel contributes to high maintenance costs. For another, a flat-roofed house is not ideally suited to the British climate (the Stevensons' damp patches are proof of that).

Alan Powers of the conservation group Twentieth Century Society mounts an intellectual defence. "The flat roof was so obviously impractical that it must have been symbolic," he says. "In part, the architects wanted to produce a cubic outline, but they were also attempting to convey a sense of leaving the earth and going up into the sky." Okay, great, but these houses leak; they are prone to condensation; the metal-framed windows rust; the asphalt roof lining warps and blisters; the render cracks and falls away. There is rarely a less inviting house than a stained and neglected Modernist box set against a grey winter sky.

The high cost of repairs is even more daunting when the house in question is protected by an English Heritage listing. Add the fact that the average Brit still loathes non-traditional domestic architecture and you end up with a house that can be very difficult to sell and thus mortgage. What use is symbolism then?

Yet attitudes may be changing as the small band of aficionados of inter- war Modernism shares its enthusiasm with a wider public. Earlier this year the Dartington Hall Trust spent pounds 300,000 on smartening up a run-down International Style house on the Dartington estate in Devon, designed by William Lescaze for the American heiress Dorothy Elmhirst in 1932. Repainted in dazzling white and cobalt blue, the house is now open to the public as a showcase for the Elmhirst collection of 20th-century art and crafts and has been deliberately presented as an exhibit in its own right.

Next year, the National Trust will be opening to the public their first Modern Movement house: Erno Goldfinger's 1939 home in Willow Road, Hampstead, which they bought this year. And, in time, the trust will inherit another inter-war classic, Holmwood in Esher, which the architect and present owner Patrick Gwynne plans to leave to the nation.

Getting a few crowds inside these seductive spaces might help to counter some of the prejudices that haunt the Modern Movement in Britain. Perhaps, in time, the practical considerations of buying a house of this period will be offset by rarity value, and the few untouched gems that remain will be snapped up. As Alan Powers put it: "Demand may be small, but so is supply." He estimates that there are barely 50 Modernist properties in the country worth getting excited about.

Among those currently for sale, the Nottingham home of a lace manufacturer, the late John Granger, is the most striking. A report written by the Nottinghamshire Building Preservation Trust says the house, "makes no attempt to harmonise with its forerunners... it is a statement of faith in the virtues of its own time, confident that the present is better than the past." In 1937 - when it was constructed on a south-facing slope of suburban Chilwell - it probably looked as startling a flying saucer.

"It was considered most odd," agrees Richard Granger, John Granger's son. "At first, local people thought it was a crematorium or an outpost for the ordinance depot down the road. In the war, I think the Germans did their best to demolish it because they thought it was some sort of observation post." He added that the house was a wonderful place to grow up in. "There are lots of light, airy spaces for kids to rush around in and in the summer we used to sleep out on the balcony. The house had delusions of existing in a Mediterranean climate."

Now Grade II listed, it was designed by a flamboyant architect, Raymond Myerscough Walker. Although originally intended to be a complete concrete round, the structure was scaled down, modified as semi-circular and constructed in conventional rendered brick to suit Granger's budget. But the architect still had plenty of scope for innovation. (It cost pounds 2,035, a fair sum in 1937.)

The main living area is arranged within one unified space, divided by angled partitions and folding doors and focused around a semi-circular room that features a wall of curved glass. The upper deck of the semi- circle is open and lit from above by a series of glass port holes set into an elliptical concrete canopy. Inside, a central staircase - which spirals around a chimney stack - leads up to a glazed, rooftop sun room. This latter feature does, indeed, have the look of an airport observation tower. Granger Senior was an aviation fanatic.

According to Richard his parents' house is a 1930s time capsule. "Remarkably little has changed," he says. "It hasn't been rewired since 1937 and it still has original sinks, chrome-plated round-pin plugs and door handles." A lot of interest has been shown in the house - "serious attacks of oohs and aahs" - but still no buyer. It's early days yet, but experienced vendors of flat-roofed homes might feel obliged to offer cautionary tales.

A listed, mid-Thirties, three-bed detached house in Nuneaton, designed by HN Jepson, recently sold for the greatly reduced price of pounds 71,500. The buyers will need to spend between pounds 30,000 and pounds 40,000 on restoration. Genia Browning's 1934 house in Plumstead Common, south-east London, has been on the market for nearly three years. In that time, two potential buyers have faded away and the price has been reduced. And although the location may not be perfect, this is a classic.

It is one of a row of four town houses commissioned by the clothing company Aquascu-tum, and was designed by the Soviet emigre Bertholdt Lubetkin (he of the Penguin Pool at London Zoo). Known to locals as "those Russian monstrosities", the four houses are now Grade II listed and Genia's boasts the original spiral staircase, bathtub and ship's port hole lamps in the hall. "Every time I start talking about the house - the dinky balcony, the flat roof, the pillars, the picture windows - I wonder why I'm letting it go," she says. "Maybe I could have sold it by now, but I'm reluctant to pass it on to anyone who doesn't really appreciate the house or the period and might not do it justice." !

BUYING INTO THE MODERN MOVEMENT

DEVOTEES of the International Style, seeking to buy a flat-roofed, concrete-rendered house with a designer label, should first try the Twentieth Century Society (0171-250 3857). A regular newsletter carries information on properties for sale and offers an "introduction" service for vendors and compatible buyers. A Twentieth Century Society journal, entitled The Modern House Revisited, by Alan Powers - which is to include an inventory of Britain's 1930s houses - will be published in January.

One recent advertisement for a Grade II listed, five-bedroomed Modern Movement house in Westcliff-on-Sea, Essex, stated that the vendors were keen to sell to other enthusiasts. Colin and Elisabeth Motteram are looking for offers around pounds 160,000. The house has been rewired, fitted with replacement metal-framed windows, re-rendered with white lime mortar and treated with solar reflective paint to protect the roof asphalt. Ring 01702 341856 for details.

Anyone interested in Bertholdt Lubetkin's 1934 town house in Plumstead, London SE18 (see text) should contact Genia Browning on 0181-854 1588. The three-bedroomed property has a garage and a 200ft garden and is offered at pounds 89,000. Buyers with unlimited cash might consider rescuing another Lubetkin classic, a 1934 listed bungalow in the grounds of Whipsnade Wild Animal Park in Dunstable. At least pounds 130,000 is needed for repairs. Price on application from Alexander & Co (01582 699990).

Raymond Myerscough Walker's three-bedroom semi-circular house in Nottingham is offered with more than half an acre of grounds through Savills Walker Walton (0115 955 2255) at pounds 215,000.

An Art Deco house of the same period is currently offered for sale through Glentree Estates (0181-458 7311) at pounds 525,000. The house in Hendon, London NW4, has six bedrooms, balconies and roof terrace and 1930s cinema-style front doors.

NOTE: the Concrete House in Bristol is not open to the public. But you can visit High Cross House (William Lescaze, 1932) on the Dartington Hall estate in Totnes, Devon (closed mid-November until April '96). For information contact: 01803 864114.