Auctions are reputed for selling properties with no roofs, loos or floors - in other words, bargains. Even so, dangers abound for the unwary, the nervous and the accident-prone, and Robert Liebman advises amateurs to be cautious, especially if hippies are lurking about. And never, ever point to the ceiling.

The house had no working plumbing, and the floorboards were permeated with urine, the stink of which was still evident throughout the property. And why not? Surveying his new home, Dennis Woodman knew, along with the rest of Lymington, that the premises had previously been the home for many decades of a recluse who took in stray and sick animals.

Mr Woodman was buying at auction specifically to bid on this one "attractive" house: "It was an oddball interesting property, going cheap, a semi-detached Victorian house in Lymington [Hampshire], three storeys, very narrow and tall with a funny attic space. It had a lot of character."

It also had a lot of history, animal history. "It was a shell, in a terrible state. Every room had been a menagerie. Every soldier [vertical upright] on the stairwell had areas worn away. Animals had been tied to them, and the wood on every one of them was worn where the animals had pulled on the leads."

Mr Woodman was fortunate in having no developers bidding for the property, but he cautions that research and self-discipline are more reliable than good luck. "I went in absolutely stuck on a top price. The walls were sound and the property was solid. I had taken advice from a local estate agent about property values in the area. Only one other person was bidding, and he dropped out just as I was reaching my top limit."

Handy with tools, Mr Woodman devoted six months to fixing up the property himself. "People must have thought that the previous owner was still there because I would occasionally find a pigeon with a broken wing or some other distressed animal that someone had left at the front door. I lived there for about four years, and when I put it up for sale, it was snapped up."

Today he lives above the shop where he sells oriental carpets from a large gallery on the wrong - quiet - side of the Underground tracks at Kew village. He bought this property the usual way, through an ordinary estate agent, but he would gladly buy again at auction. "In fact I've bid at other auctions but got raced out of the bidding."

Many homebuyers attend auctions seeking unusual properties that were not originally intended as residences. A decommissioned school in the West Country attracted many buyers interested in the property as a residence, but one group of buyers had another use for it in mind.

Karlin and Greta Rushbrooke were part of a group of local parents who, alone among the potential buyers, wanted to use the former school as ... a school. "We'd been running a Steiner school in people's homes and then the village hall," says Mr Rushbrooke, "but as our numbers grew, we needed something permanent."

The school consisted of a big hall, a headmaster's room, working loos, and - crucially, as it turned out - a bit of land that the school had bought from a farmer. "There were rumours," says Mr Rushbrooke, "that the farmer did not have the right in the first place to have sold the land to the school."

One member of their group was an accountant who looked presentable, actually owned a suit, and was shrewd. "He was the front man for our group of hippies, who were hiding in the back. Before the bidding, he asked the auctioneer if the rumour was true, and the auctioneer confirmed that there might indeed be a title dispute." Mr Rushbrooke thinks that, thanks to that reply, at least some would-be buyers were put off. Victorious in the mild bidding war that ensued, they paid many thousands less than they had anticipated.

Immediately on completion, they opened the new school with an enrolment of 30 and now have 240 at the Hereford Waldorf School, in Much Dewchurch. Taking advantage of the 40-foot ceiling, they added a storey, and their one-room facility now has four classrooms. They also converted an adjacent barn into a classroom. Any title dispute as there may have been has floated wispily away.

Auctions are hardly safe places for people with nervous dispositions and impulsive natures. If you are the successful bidder, you must pay a deposit right then and there. You can't change your mind. You can't plead that you made a mistake.

"Once the property has been sold in the auction room, a legally binding contract is created between seller and buyer. The buyer pays a deposit, usually 10 per cent, and a completion date is immediately fixed, usually 28 days after the auction," says a Halifax spokesperson.

Many properties are open for viewing at a specific time and day designated in the catalogue, and surveyors can make separate appointments. Chris Berriman, partner and auctioneer at Allsop, advises buyers to follow three golden rules before attending the auction: "Arrange finance, get legal advice on the particulars of the property you are interested in, and arrange a survey." Such preparations may require a month or more.

Dozens of auction houses sell properties in scores of locations. A copy of the weekly magazine Estates Gazette, which lists forthcoming auctions and also provides prices realised in recent sales, is a good starting point.

A lot of legwork can be saved by subscribing to AuctionWatch which, as its name suggests, watches auctions, conducting daily searches through dozens of catalogues from 80 auction houses nationwide. It has 15 residential auction houses in London alone. Subscription costs pounds 110 for three months, or pounds 350 for a full year. The AuctionWatch computer highlights properties according to the subscriber's requirements in terms of location (town, county, postcode), property type (house, flat, office, shop) and other characteristics.

Allsop & Co, 100 Knightsbridge, London SW1X 7LB, 0171 494 3686; Halifax, Trinity Road, Halifax, West Yorkshire HA1 2RG, 01422 333 333; AuctionWatch, 5-7 Old Town, London, SW4 0JT, 0171 720 5000.