Architecture: Home is a little mud hut in Dagenham: Don't dismiss it as primitive, says Sumita Sinha. Earth architecture is cheap, strong and ecologically sound

THE idea of building in mud inevitably conjures up visions of primitive huts in Africa and India. This summer, Desiree Ntolo, a 34-year-old mother of six, completed a 7ft-high, 54ft-long hut from 20 tons of Essex mud in the garden of her house on the Becontree Estate in Dagenham. She said she wanted to remind herself of her childhood home in Cameroon, to have somewhere to escape from her children and to practise her religion.

Neither her neighbours nor the local council have been amused, and there is little doubt that Mrs Ntolo's loose interpretation of a traditional West African home has reinforced the poor reputation of mud as a building material. She has been told by Redbridge council that her hut must go because it does not fit into the local vernacular (red brick, aluminium-framed double glazing, neo-Georgian fanlight doors, crazy paving up the walls). But she intends to fight tooth and nail for it. It will last a hundred years, she says.

Today, mud is generally considered to be the least respected building material. Yet from Devon to Delhi, mud architecture is part and parcel of our daily lives. It is estimated that more than one- third of the world's population lives in mud buildings. In the South-west of England mud buildings are surprisingly common; 'cob', as the material is known, is made from mud, chopped straw and - sometimes - broken pottery, churned together and placed in horizontal layers to form walls.

Laurence Keefe, secretary of the Devon Earth Building Association, estimates that there are at least 20,000 houses constructed either fully or partly in cob, along with an equal number of barns, outbuildings and boundary walls in Devon alone. Windswept and rain-beaten cob houses have survived for centuries, with walls sheltered by waterproof plinths and deeply overhanging roofs (usually thatched). There may be more, he says, but many are hidden under coats of lime-wash or paint.

In large areas of rural France, mud houses have long been popular, and today they are very much back in fashion with Gallic architects and home builders. Among their advantages is cheapness - they cost only 5 per cent of their brick or concrete equivalents because mud requires neither firing nor baking and can be excavated on site. And they are cheap to heat: tests have proved that 2ft-thick cob walls have more insulative properties than the minimum required by British building regulations. Mud is also environmentally friendly. It requires little energy to extract, shape and prepare and, dug back into the ground, it is readily disposed of when a building is demolished.

Mud has traditionally been used in three different ways: as sun-dried bricks, cob (also known as 'adobe'), and rammed earth or pise, which is popular in France. All three methods have their limitations. Sun-dried bricks can be weak. In cob construction, one layer of mud has to set before the next can be added, so progress is slow. Rammed-earth walls are formed by forcing mud between wood shuttering, which is removed when the mud is set; this means that walls must be straight. Today's mud builders, however, are turning to rammed-earth bricks, made by squeezing mud, often strengthened by cement, lime or bitumen, into standard brick-sized moulds; this can be done on site by hand or mechanically in brickworks.

Despite its cheapness, simplicity, strength and ecological soundness, mud is treated with suspicion in Britain. 'People who have cob houses or who want to build in cob or earth find it very difficult to obtain mortgages and insurance,' says Tristan Peat, a local Devon planning officer, who is writing a doctoral thesis on mud building.

'British mortgage companies,' he adds, 'hold a very conventional view of mud architecture; so does the architectural establishment. . . . There is no encouragement to ordinary people to build anew in mud.'

In France, there is less prejudice against mud, and Craterre, an organisation with offshoots in Switzerland, Germany, Australia and New Zealand, has carried out extensive research and building projects in such architecture over the past 10 years. For example, Isle d'Beau, in southern France, a haunt of artists, is now also a centre of modern earth architecture courtesy of Craterre.

The British have been slow to follow the French lead, but the Devon Earth Buildings Association is showing the way, and the Plymouth School of Architecture has started a two-year research project on mud as a building material for the future.

The latest significant cob building in Devon was built in 1912, designed by an Arts and Crafts architect, Ernest Gimson. Eighty years from now, there may well be a whole new wave of ecologically inspired mud buildings. Mrs Ntolo's hut might be unpopular today, but it is one muddy step forwards into the age of cheap, thermally efficient and recycleable architecture.

The writer is an environmental designer. She has worked on mud buildings in France, and received a Unesco award for her efforts in 1987.

(Photograph omitted)