For most homeowners, buying a home is the biggest single investment they'll ever make. So before you let a stranger come in and smash walls, tear out appliances and crunch holes in the ceilings of your biggest financial asset, it might be a good idea to find out exactly who you're dealing with.

Once you've found a home equity loan and figured out which remodeling projects will give you the best return on your investment, you may think all you have to do is kick back and daydream about marble countertops and game rooms.

The quickest way to get nailed on your home improvement projects, though, is not doing your homework on your contractor.

The Remodeling Activity Index, released Jan. 18 by Harvard University's Joint Center for Housing Studies, found that Americans spent $168.7 billion on home improvements last year, up 1.5 percent from the 2005's total.

Lots of work means lots of contractors. And lots of ways to get scammed.

Slam the scam
Last year, the Better Business Bureau received 6,489 consumer complaints regarding construction and remodeling services, ranking relatively high at 22 out of 2,900 complaint classifications.

Sheila Adkins, director of public affairs for the Council of Better Business Bureaus, says there are three main reasons for the flood of complaints.

3 main reasons for complaints:

1. Homeowners don't get all the details written into the contract before signing it. 2. Homeowners select a contractor based on price alone, without investigating their background. 3. Homeowners get duped by outright scams.

These fly-by-night artists fall into three broad categories. There's the con man, an outright criminal who promises anything at any price, demands his money up front and then vanishes. Then there's the lowball artist, a shady operator who intentionally bids below his legitimate competitors, then makes costly changes or skimps on workmanship to recoup a profit. Last, there's the slipshod businessman whose intentions may be honorable but whose incompetent estimates and overall poor judgment end up costing you money.

"These are the door-to-door home contractors who claim to be doing a job at your neighbor's house, they have leftover materials and would be happy to patch your leaky basement, repave your driveway or check your furnace," says Adkins.

Protecting yourself against the con artist should be easy, she says.

"Contact your local BBB and ask for a list of members in that industry. That's just being a wise consumer," Adkins says. "If you're spending several thousand dollars, I think you want to make sure you're giving it to a reputable company."