ºÃÉ«ÏÈÉúTV

A volcano has just erupted in Central America and 150,000 people have been evacuated from a nearby town. The eruption is accompanied by two earthquakes, and more are expected. Aerial photos suggest that 3000 houses have been destroyed, making 24,000 people homeless; fire, earth tremors and pillaging have affected the homes of another 60,000.

What are the immediate needs of the local population? That's the question confronting a quantity surveyor from London, a builder from the West Country and an Australian engineer – and they're arguing passionately about what to do. Should they set up a hospital first, or ensure there's a supply of clean water? Should they house the homeless in makeshift tents, or does it make more sense to rebuild their homes?

Fortunately, this scenario isn't real. The participants are sitting in a classroom at Harper Adams College in Shropshire, taking part in a course on planning and building refugee camps in disaster-stricken parts of the world. The four-day, £620 course includes theoretical and practical exercises: later the participants will venture out onto a windy field to erect shelters ranging from primitive huts made from found materials to more sophisticated timber and tin structures.

Once they have completed the course, they could find themselves practising their new-found skills anywhere in the world. "The provision of shelter in disaster-affected areas has become more of an issue recently," says Tim Hayward, training manager at RedR, the register of engineers for disaster relief and the body that is organising the course. "In the early 1990s, most people would have been thinking about providing plastic sheeting shelters for Africa. But now shelter provision has moved up the technical scale."

For years it appeared that humanitarian crises happened mainly in developing countries in the tropics, where housing standards are relatively low. But recent conflicts in the Balkans and former Soviet states such as Georgia and Azerbaijan have brought large-scale disasters to temperate climates where populations are used to higher standards of living. In Afghanistan, the return of more than a million refugees in recent months has created a pressing need for adequate housing before the vicious winter sets in. Tented refugee camps are not appropriate in these areas. Instead, help is required to build well-equipped temporary housing or to rebuild war-damaged buildings. In the Balkans, a huge programme is making thousands of derelict houses habitable again. To carry out this work, agencies such as Oxfam and the Red Cross are increasingly turning to the construction industry for help.

RedR was set up in 1980 and has grown in response to this need. It acts as a "dating agency", matching professionals to disaster-relief operations. It selects volunteers according to their qualifications and experience, and has more than 1000 people on its books. "The original idea was to set up a mechanism whereby engineers can be identified and made available to relief organisations such as Oxfam," says Hayward. "The bulk are engineers – mostly water and sanitation engineers – but it's spreading rapidly and diversifying to non-engineering areas such as logisticians, project managers and administration and finance people."

Hayward, 44, is a water engineer who spent five years abroad, providing sanitation for refugee camps in the Balkans, Africa, South America and Asia. He helped to build the massive camps required to house the million Hutu refugees who fled Rwanda after the genocide in 1994. Later, he provided water and sanitation for 90,000 refugees in Kosovo. Hayward now works full-time for RedR.

The organisation's operations room is in the basement of the Institution of Mechanical Engineers' imposing headquarters in Birdcage Walk, a stone's throw from the Houses of Parliament in London. The walls are decorated with political maps of the world and a whiteboard listing staff out in the field (Brazzaville in the Congo and Jakarta in Indonesia on the day of ºÃÉ«ÏÈÉúTV's visit). Souvenirs such as African masks and Russian dolls line the windowsill, and the filing cabinets are decorated with stickers advertising relief organisations, including one that says "Join the Pakistan army". "We had a team training in Pakistan," explains Hayward.

In the UK, RedR's courses have burgeoned from practical ones such as shelter-building, sanitation and roads and crossings to topics such as motivation, team-working and humanitarian practice. The technical requirements of relief programmes are usually lower than most people have to meet in their normal jobs but the work requires an enormous amount of tact and sensitivity. "The way you do things is as important as what you do, otherwise you can seriously upset people and do an immense amount of harm," says Hayward.

The organisation increasingly helps to train local people on the ground, reflecting the trend towards helping people to help themselves rather than "parachuting white people in", as Hayward puts it. "There's a growing sense of responsibility towards the way you operate – thinking about what you can do to reduce the community's vulnerability to it happening again. That involves thinking about sustainability and recruiting local people." RedR is training people in countries such as Kenya, Rwanda, Kosovo and India.

But the bulk of RedR's work is maintaining its database of UK volunteers and responding to requests from aid agencies. Volunteers tend to be released by their employers for a few months, although Hayward says people are now spending longer periods abroad as they find the work so fulfilling. RedR says it has no problem attracting keen young professionals but struggles to find experienced senior people – particularly those with project management skills. For these people, spending long periods abroad can be impossible to juggle with family and career commitments.

People apply for relief work for a number of reasons, says Andy Bastable, Oxfam's public health engineering co-ordinator, who has recently dispatched engineers to Peru and Brazil to replace flood-damaged housing. "There are different kinds of motivation to do it – wanting to feel you make a difference in the world, wanting to go abroad, feeling bored with your job at home in England."

The way you do things is as important as what you do, otherwise you can seriously upset people and do an immense amount of harm

Tim Hayward, RedR training manager

A stint helping to rebuild a shattered country can be a rewarding experience and provide a worthwhile career break. However, Bastable warns, relief work is complex, potentially distressing and poorly paid – and unsuitable for either Rambo-types or do-gooders.

"It's mainly the younger engineers who do this kind of work, because there's such a pay gap – the first time you work for an aid agency you earn about £600 a month, compared with an annual salary of about £25,000 for a young engineer. The trouble with people on the RedR list is that their employers only let them go if it's a high-profile emergency – if it's low-profile or a non-emergency situation, their employers won't let them go."

He adds: "There are lots of them that we wouldn't consider because they don't have any experience – we need people with both building experience and overseas experience. If people want to get some experience, they should start with another agency like Concern or Médecins sans Frontières."

Bastable, who also started out as a water engineer, says Oxfam is focusing its efforts on training local people in settlement reconstruction as well. "We want to recruit local engineers – it's not appropriate if people are giving advice in a country they have never visited before," he says. "I was recently in Kabul; they were training women engineers who had originally been trained by the Russians but weren't allowed to work under the Taliban. I set up eight-week refresher courses taught by a mix of Afghan men and foreign women. The women sent out to teach had to adapt their courses for the 18th century – the Afghan women couldn't use computers."

Afghanistan is the focus of one of the largest refugee repatriation programmes in recent history. An estimated 4 million people fled the Taliban – mostly to Pakistan and Iran, and about 1.4 million have returned to their homeland in the past few months. Aid agencies have been overwhelmed by the scale of the operation.

Natasha Covernton, an administrator at the United Nations High Commission for Refugees, says plans to rebuild the country's shattered housing stock and infrastructure have had to be put on hold while aid agencies deal with the flood of returning refugees. Instead, the commission is handing out shelter kits – containing 20-30 wooden poles, a door and two window frames as well as nails and tools – to allow people to rebuild their homes before the onset of winter. It had originally planned to distribute 97,000 kits, but it now urgently requires funds to provide more.

The situation is similar in Kosovo, where ethnic Albanians who fled ethnic cleansing are finally returning to their villages to find their houses destroyed. In the village of Biti e Ulët in Strpce province, 100 Albanians are attempting to rebuild their damaged homes before the winter.

"All we need is a little assistance," one of the villagers – a 54-year-old father of seven called Miliam – told the UNHCR's website. "A little bit of concrete and bricks would really go a long way. We can reconstruct the houses ourselves." In situations like these, financial donations are more useful than Western construction expertise. "We try to get local people to do the construction," says the Covernton. "If the construction industry wants to help, the best thing it can do is donate money."

Longer term, bodies such as the UNHCR will require experienced industry personnel to help rebuild Afghanistan's infrastructure but Covernton points out that getting selected for the work is not easy: "Competition is really tough and there's a really complicated selection procedure. We need to make sure the work is spread out between different countries – not all going to British engineers, for instance."

People who have worked on aid programmes say that the politics and infighting between the competing aid agencies can be distasteful to witness. "My own personal feeling was that the UN was extremely ineffectual," says Alastair Mellon, who spent eight months housing refugees in Bosnia in the early 1990s and who is now managing director of construction portal Asite. "There were a lot of poseurs writing reports and driving their girlfriends around in armoured cars."

Mellon, a qualified civil engineer, organised the provision of shelter for 15,000 people on behalf of the UNHCR. He says that disaster relief is not for the faint-hearted. "There were five different armed groups operating in the area; negotiating with them all was a bit like 3D chess. Many of the buildings we fixed up were sequestrated by one or other of the factions. It was potentially quite dangerous. There were an awful lot of drunk people wandering around with guns.