God be with the days when the first thing anyone building a house in the countryside had to do was to square their plans with the fairies. That sort of superstition would be shunned by the bungalow-builders of today, but it was a real consideration for their predecessors, as I discovered in researching the book, Ireland's Earthen Houses. For centuries, most people in rural Ireland housed themselves in small cabins, made from whatever materials were most plentifully available in the locality. In the west, for obvious reasons, these houses were made from stone, but in the midlands and along the east coast, where stone was not so readily available, clay was the favoured material.
Before building work started, the site would be marked out by placing large flat stones at the corners, each with a smaller stone on top, to be left there overnight. If they were still in place on the following day, it was a taken as a sign that the prospective dwelling was not being built across a path used by the "good people", or slua si of Irish mythology.
Making a clay house began by mixing the marly sub-soil excavated from the earth. Chopped straw was added to the mix as it was turned over and sprinkled with water, then it was left to "sour" for a few days until it was sufficiently firm to use as a building material; the test was whether it could stand 18 inches wide and a foot deep without bulging.
By then the stone foundations, usually nine inches deep and rising another nine inches above ground level, would have been laid before the mud walls were raised using a graip or sprong - a long-handled implement with four flat metal prongs at the end - to manipulate the clay, patting it down to improve its adhesive properties.
In the better houses, chimneys were raised in stone. But many cabin builders relied on using strong pieces of forest timber through which holes were bored five or six inches apart and filled with standard rods of willow or hazel. Then, the whole frame was interlaced with wicker-work and plastered over with a mixture of daub and cow manure.
Rough timber was used to form the roof which was usually hipped or half-hipped and thatched with straw or reeds or, in the case of poorer dwellings, rushes or heather. And at the end of it all, though made from clay, the builder would have a house that was "neat, cleanly and commodious", as the Irish Farmers Journal noted in 1814.
"With a compost of moistened clay and straw, without plumb, square or level, but merely with an instrument they call a sprong . . . every man is capable of erecting a house for himself, compact and perpendicular", the journal marvelled. Only the scale varied with the circumstances of the proprietor - large for the affluent and small for the poor. More mud houses have survived in Co Wexford than anywhere else. One of them, at Pollwitch, near Johnstown Castle, has attracted visitors from far and wide. The Wexford People noted a few years ago that a team of University College, Dublin academics "spent a day drooling over the place" and returned to Dublin "having photographed every nook and cranny."
During the Emergency, Dublin architect Frank Gibney suggested that people should be encouraged to build in clay because of its widespread availability. He also argued that clay-built houses, in terms of their design, construction and insulation properties, were "superior to many of our modern, standardised thin-walled cottages".
The only impediment to reviving the ancient art that he could see was "a psychological one, for public opinion may appear hesitant in considering an idea associated with `mud cabins', peasantry and poverty". And indeed, the prejudice against this most vernacular of Irish building types was so entrenched that his plea fell on deaf ears.
It would be impossible to exaggerate the pervasive nature of this prejudice; it is part of our cultural baggage. As long ago as 1878, the Irish Builder lamented that mud cabins were "still, alas!, too plentiful" and sought to have these "barbarous relics" replaced by "a better class of human dwellings in stone, brick and concrete materials".
Yet, even today, it has been estimated that earth structures embrace some 30 per cent of the world's population, housing no fewer than 1.7 billion people. The indelible stamp of earthen architecture is to be seen almost everywhere, from the humblest shelters of Africa to the adobe houses of California and the castles of the Saone valley in France. According to Hugo Houben, a French architect based in Grenoble, building with earth is also the most efficient way to produce housing in the developing world. The material is widely available, it is economical to use and also has the advantage of being both culturally and climatically suitable; it is the essence of "sustainable development".
Britain has tens of thousands of mud-walled, or cob, buildings - mostly in the southwest of England. "After cob was dismissed earlier this century in favour of mass-produced bricks and concrete, this most green of building methods is coming back into favour", the London Times reported, in a 1995 article on the Devon Earth Building Society.
It featured an attractive four-bedroom cob house built by Kevin McCabe near Coylton, in east Devon. "The materials he used could not be more indigenous: 70 tons of soil from his back garden, mixed with 30 tons of locally quarried silt and stones to reduce shrinkage, and 120 bales of straw from nearby farms." The roof, of course, is thatch.
With its good "overhang", which Mr McCabe believes is even more important than the material itself, the house should last for 1,000 years. "The lovely thing about cob is that it looks organic; and it looks like it has been here forever." And because of its good insulation properties, the McCabe family's fuel bill for the previous winter was just £200.
In Ireland, however, we place little or no value on our own vernacular architecture, still less on thatched mud or clay houses. State aid for the relatively few that survive is minimal and confined to small grants towards re-thatching; the intrinsic value of the house itself is largely unrecognised. We don't even know how many of them still exist. And unlike Devon, there is no effective lobby to preserve this valuable and irreplaceable link with our past. As we get on with building modern bungalows in the countryside, with ostentatious PVC porticos and landscaped gardens borrowed from suburbia, is it not too much to hope that we might save what is left of where we came from? Ireland's Earthen Houses, by Frank McDonald and Peigin Doyle, with photographs by Hugh McConville, is published by A&A Farmar, price £4.99.