Like most homeowners, Norma Nickels had heard of a mechanic's lien but didn't really know what one was or, for that matter, that it could affect her, until it was too late.

“It just kind of blindsided us,” she said.

Nickels hired a roofer to put on a new roof. She paid $2,800 up front and another $2,800 when it was complete. Everything was great until she says, “Someone showed up at our door at 9:30 at night. A bail bondsman was serving a notice of a mechanic's lien.”

Nickels says the roofer never paid his supplier for the roofing supplies, a growing problem in trying times. Instead of going after the roofing company, the supplier filed a lien against the Nickelses' home.

That's a common method that subcontractors and suppliers use to get their money, according to Matt Morrow, executive officer of the Home Builders Association of Greater Springfield.

“The idea is their work has added value to property so ultimately responsibility with getting paid would be attached to property itself," said Morrow.

The Nickelses tried to get the roofer to pay, to no avail. Instead, to satisfy the lien, they had to pay the supplier $1,500. That's on top of the $5,600 they had already paid for the new roof.

“We don't feel like we owe this,” said Nickels. “We've paid it once. Why aren't you going after person that did this -- the contractor?”

Strangely, the Nickelses were actually lucky. Many homeowners go years without knowing about liens, until they try to sell, refinance or borrow against their homes and find out they can't until they pay off the liens.

“It's imperfect and clunky because it ultimately holds responsible the party who is not responsible for non-payment," said Morrow.

It's not only building suppliers who can file liens. If you don't pay your general contractor, he can file a lien. If your general contractor doesn't pay a subcontractor, such as a roofer or plumber, the sub can file a lien. Or, as in the Nickelses case, if that subcontractor doesn't pay the supplier, it can file a lien, too.

There are some steps you can take to protect yourself.

“Make sure you're working with someone with good reputation, member of a local HBA, carries insurance and has references," said Morrow.

Morrow also says you should make sure you get title insurance if you're buying a new home or a newly remodeled home. This protects you if a lien is filed after you move in.

Perhaps the best tip is to negotiate with the contractor an installment plan that lets you withhold final payment until you get lien waivers from everyone involved with the project. This prohibits them from filing liens on your property.

“Particularly with the final installment, it's certainly appropriate to get lien waivers that are releases that all bills are paid,” said Morrow.

The reason we didn't name the Nickelses' roofer is because, after a reporter contacted him for a comment, late Wednesday afternoon he called back. He admitted he didn't pay the bill because of financial problems in a slowing economy. He said he has, however, been saving up to pay back the Nickelses and, after our phone call, he agreed to get a cashier's check for the $1,500. He took that check to the Nickelses on Wednesday evening.