One northern Virginia homeowner's remodeling troubles began when, after accepting a large deposit, her contractor took off for a month's vacation.

But that was just the beginning. By the time a one-room addition was completed, three months behind schedule, its skylights were backward, its roof didn't line up with the main roof of the house and its siding didn't match the rest of the house. As a result, the homeowner has spent thousands of dollars on lawyers and corrective work. "It's just been a nightmare," she said, asking not to be named. "We have a nice house and wanted a nice addition. We didn't expect someone to slap on a lean-to."

While this is an extreme example, there are many other homeowners in northern Virginia and throughout the area who have suffered at the hands of incompetent or unscrupulous home remodelers. And people in the contracting business say the number of remodelers doing inadequate work may be on the increase.

"We call them 'character contractors,' " said Laurence Sexton, coordinator for the remodelers council of the Northern Virginia Builders Association. "We're constantly hearing of people doing poor work. It's not that hard to set yourself up as a contractor, and because it's easy to get into, it's easy to get out of and easy for the consumer to get burned."

Sexton said complaints range from windows that won't open because they have been installed incorrectly, to fireplaces that don't work, to poor reroofing jobs, to additions and even whole houses left unfinished. "We get a lot of calls from people who can't get the contractor to come back and complete the job," Sexton said.

The Better Business Bureau of Metropolitan Washington lists home remodeling as the 13th biggest cause of complaints, right behind mail order catalogues, automobile repairs and television repairs.

"We do have problems with home builders and remodelers, definitely," said Kate Nyland of the northern Virginia Better Business Bureau. "Particularly from people who hire contractors without checking to see if they are licensed."

With the high cost of housing, Sexton said, he expects that in the future more people will choose to remodel older homes instead of buying new ones, a trend that could lead to an increase in the number of incompetent contractors looking for work.

"Nobody's going to go in and tear down whole subdivisions like they used to, because the houses are too valuable," said Sexton. "And with all that remodeling work, you'll see these guys licking their chops at all the money to be made in contracting."

While many of the 2,000 home remodelers working in northern Virginia are competent, the members of the Northern Virginia Builders' Association agree there are many who aren't. They advise homeowners to be wary of unsolicited offers of work and of door-to-door sellers peddling home-improvement products.

"Homeowners have got to do their homework," Sexton said. "A lot of people get into trouble because they don't know what they want. They should know something about the work to be done and look into what kind of products will be used."

When asking for bids, Sexton advises, get offers from three to five contractors and be wary of any bids considerably cheaper than the others. Work only with contractors who are licensed and have adequate liability insurance. Ask each contractor to supply you with names of people they have done similar work for, then talk with these people and ask to see the work the contractor did.

Check with the local Better Business Bureau, Chamber of Commerce and builders' associations for recommendations of remodelers or records on contractors bidding on your project.

Candy Von Salzen, vice president for operations with the Washington Better Business Bureau, said that homeowners should put every promise, guarantee and warranty in the contract, including the completion date, a penalty clause, a payment clause detailing who determines when the job is finished and when final payment will be made, specific products to be used and a mechanism for resolving disputes.

Once the contract is signed, do not give a contractor a deposit for more than 15 percent of the cost of the entire job, Sexton warned. "A good businessman shouldn't have to rob Peter to pay Paul. If he is reputable, he will have a good credit line with his suppliers."

If the work is not done on time or according to the specifications of the contract, hire another contractor to examine the work, Sexton advised. If the second contractor says the work is poor quality, stop making payments to your contractor and contact a lawyer, he said.

"Many of these remodeling jobs are a major investment, and when a contractor enters your home he is entering your castle," Sexton said. "It's much cheaper in the long run if you get the job done right the first time."