For new homes, Bruce E. Holmes, a public engineer based in Palm City, Fla., said he mainly looks for problems with fit and finish (such as walls that aren't straight), potential for leaks (such as a poorly connected hookup for the dishwasher) and mismatched electrical breakers (often found in the connection to the air conditioning compressor). He also checks for hot and cold water lines that are reversed.

New houses get independent inspections in one or more of three phases: while they're being built, after work is completed but before the buyer moves in, and 10 or 11 months after the buyer takes possession. Why so late? Because most builders offer one-year warranties on cosmetic items. The inspector can provide a list of repairs to be made under warranty.

Not everyone can have the house inspected while it's being built. Many tract-house builders won't allow outsiders on site. Custom builders usually are more flexible.

"The best time with a custom home is when it's dried in and all the walls are up and the electrical is in, prior to sheet-rocking the house," Holmes said. "Then you can see if you have your outlets and light fixtures in the right place."

Francis DeSouza, an accountant in Loudon County, Va., whose 3,200- square-foot house is under construction, made sure an independent inspector was given access to the site. "I knew I needed an expert opinion before they threw the dry wall up there," he said.

The inspector was at the site for three hours and found things like cracked floor joists, missing hangers on studs and missing fire blocks. A county inspector already had passed it.

DeSouza and the construction supervisor later walked through the house together, checking off items on the inspector's list. The builder told DeSouza which problems he would fix and which he wouldn't because they were too minor. After DeSouza approved the fixes, the walls went up.

"The pre-dry-wall inspection was very worth it," DeSouza said. "I recommend it to anyone who doesn't know a lot about building houses."

He is considering hiring his inspector to go through the house after construction is finished and right before closing. At this point, the inspector looks for faults such as crooked walls, missing handrails, trip hazards caused by floors that aren't on the same level from room to room and bathroom vents that exhaust moisture into the attic instead of outside.

A few people hire inspectors to examine houses in the month or two before the one-year warranty ends. This inspection isn't as common because owners have lived there almost a year and already know what's wrong with the house.

Naturally, inspectors insist that it can't hurt to have another set of eyes take another look before the warranty expires.