Indeed, more than 40 percent of the previously owned homes on the market have at least one serious defect, according to HouseMaster, a major home inspection company with offices in more than 390 cities in the United States and Canada.

"Virtually every 'used' home needs some repair or improvement," said Kathleen Kuhn, CEO and president of HouseMaster. "That's to be expected. But with today's high prices, you want to make sure that you are aware of any major problems in a house you are considering purchasing, and what it will take to remedy the situation."

Drawing from their own findings from more than one million home inspections, HouseMaster says the most serious home defects to be on the lookout for are:

1. Cracked heater exchange
2. Failing air-conditioning compressor
3. Environmental hazards including radon, water contamination, asbestos, lead paint, and underground storage tanks
4. Moisture in the basement
5. Defective roofing and/or flashings
6. Insect infestation -- termites or carpenter ants
7. Mixed plumbing
8. Aluminum wiring
9. Horizontal foundation cracks
10. Major house settlement
11. Undersized electrical system
12. Chimney settling or separation

Kuhn says most of these problems can be repaired. However, depending on the specific problem, the cost can be substantial, particularly if the defect involves one of the major systems. The cost could become a factor in whether you ultimately buy the house.

For example, a new air conditioning compressor could cost you up to $1,200. A new roof or repairs can cost at least several thousand dollars. A wet basement could cost up to $5,000 to remedy.

If you enter negotiations to buy a particular house, your agent should advise you to provide a provision for renegotiating or backing out of the contract if a home inspector finds major problems.

"If the property inspectors find that little or no corrective work is required, you have little or nothing to negotiate," say Eric Tyson and Ray Brown in their book, Homebuying for Dummies. "Suppose, however, that your inspectors discover the $200,000 house you want to buy needs $20,000 of corrective work for termite and dry-rot damage, foundation repairs, and a new roof. Big corrective work bills can be deal killers."

If repairs are needed, there are several ways to proceed if you still want to buy the house, the Dummies book advises.