Architecture: Will you be home for Christmas?

The bundles of fir trees in the football stadium at Srebrenica in Kosovo are not Christmas trees. A present from the authorities, they will become posts or beams to help resettled Muslims and Christians rebuild their homes amid the rubble.

Winter has come early for the people who poured back into Kosovo after the borders opened in June. Hundreds of thousands of refugees are glad to be home, even if it is in ruins - but as the weather worsens, the crisis deepens. The capital, Pristina, is cloaked in fog. Water pipes are broken. Phone lines are down.

"I have videos of whole villages in which nothing was untouched by the bombing," says Tom Ehr, director of Warchild USA, the charity that helps children traumatised by war. "Everything was razed to the ground... It was heartening to see people taking responsibility for themselves in a flurry of rebuilding." Now the only flurry is the snow falling in the mountains, where sometimes the only roof over people's heads is a blue plastic sheet handed out by the UN High Commission for Refugees.

Back in July, Warchild USA sponsored an online competition called Architecture for Humanity, which asked architects to design temporary housing for the Kosovans. The brainchild of a 26-year-old architect Cameron Sinclair, the competition specified that each shelter has to last at least five years and cost under pounds 5,000, the amount used in Bosnian reconstruction. Big enough to house 10, it had to be simple enough to be erected quickly on different terrains, from mountainous regions to muddy flats. The pounds 15 submission fee paid by the 200 architects from 33 countries went to help match opera singer Luciano Pavarotti's $1m donation to Warchild to rebuild 22 schools across Bosnia.

Warchild is now seeking a sponsor to prototype one or two of the shelters and field-test the design in Kosovo before mass producing it. Tom Ehr knows that, realistically, it will come too late for the Kosovans, but hopes that the project will be a test case for the next crisis. "It would be great if these structures could be mass-produced, ready to air-lift into the next trouble-spot," he says.

If a sponsor is found, Kosovans could find themselves living in a designer version of the yurt, the age-old Mongolian felted tent. Inflatable plastic houses and shelters made of hemp are also possible solutions. At least there are no portakabins. "Just because it is temporary doesn't mean it has to be a box with a hole cut into it," says Cameron Sinclair. He left the judging to top young American architects Stephen Holl, Todd Williams and Billie Psien, helped by celebrity human rights advocate Bianca Jagger and relief expert Herb Sturz from Open Society Institute.

Cameron Sinclair would really like to see Japanese architect Shigedu Ban's house of paper tubes - like the ones posters are rolled into - built in Kosovo. Its great advantage is that the machine can be tractor-driven to any site to recycle any old paper into tubes, insulated on the inside and weatherproofed with thin aluminium on the outside. The material cost is low, and the houses can easily be built or dismantled by people with no knowledge of construction. The first 16-metre-square paper log house was built at Kobe after the 1995 earthquake, where the lightweight, recyclable, disposable structure reassured victims who feared another quake.

It is that trauma factor that the only British contender in Architecture for Humanity, Mike Lawless from LDA architects believes that architects should confront. "It is impossible to understand how distraught people in Kosovo are, mentally and physically," says Lawless. "If you asked people to come to an army base to carry materials up the mountainside, they can't. They have to guard the family cow in case it is stolen. Or eaten."

Lawless, who is working with Mark Whitby and Whitby & Bird engineers, designed an insulated aluminium foil panel. The panels can be Velcroed together to form a sheet of the required dimension to be thrown over rubble - or the steel frame of a shelled-out building - like a duvet cover. For more substantial walls, the duo hit on the idea of using the mesh cages (called gabions) that motorway engineers pack full of rocks to shore up cliffs. There is no shortage of rubble in Kosovo, and when the shelter is no longer needed, just loosening the cages will get rid of it.

Between 1995 and 1997, Mike Lawless worked in Mostar in Bosnia for Warchild, helping a Bosnian contractor to design and build the Pavarotti music centre to help the children of the war with music therapy. The centre was built on the ruins of a 19th-century Austro-Hungarian school. Only the basement remained; there, Brian Eno gave music lessons to the children while the architect in fingerless gloves drew plans by candlelight during the curfew.

They had to sleuth everything: pianos from Finland, ironmongery from Germany, plasterboard from Sweden, furniture from Spain. After designing the restaurant and bar, devising the menu and teaching the chef, the architects stacked a van with Ikea tableware kits in England and drove it back, at their own expense. "Why did we do it? Because of the people who were there. When you see them devastated, through no fault of their own, there are reasons beyond the commercial rationale."

Mike Lawless thinks that it is time architects started building for human beings instead of designing symbols of corporate power. So he went on to Vitez in Bosnia to design a youth centre in no man's land between the Croats and the Muslims. His aim is to get youths off the street, "to get them treatment and stop them sleeping in rubbish bins and burnt- out cars - you can't believe it until you have seen it." In the middle of what used to be the football ground, this lively centre, patrolled and protected by the Croatians, is the face of architecture with a social conscience, brokered with the local community across a great divide.

Architecture for Humanity: Transitional Housing for Kosovo is at the Royal Institute of British Architecture, 56 Portland Place London W1 until 22 January

The Independent's Christmas Appeal is for Warchild UK (see p3, main section)