Don't buy a house that hasn't been thoroughly inspected from foundation to roof.

You can't tell how much corrective work a house needs by looking at it. How do you know if the roof leaks or if the electrical system is faulty or if the plumbing is shot or if there's termite damage or if the chimney is loose or if the furnace has a cracked heat exchanger or if . . . ? These "invisible" defects cost BIG bucks to repair.Whether you're a buyer or a seller, you'll be involved with some or all of the following property inspectors:

- Contractor. Always have your house inspected by a licensed general contractor prior to buying it. This applies whether you're buying an old house or a brand new one. Because the house is new doesn't mean it was built properly.

You also need a contractor's inspection if you're buying a condominium or cooperative apartment. When you buy an apartment, you buy into the whole apartment building. As a co-owner in the building, you'll be assessed for your share of corrective work done in the building's common areas, such as the roof, foundation, plumbing, electrical, heating and cooling systems.

Your contractor should advise you on the physical condition of all the property's interior and exterior components. He'll inspect the roof and gutters, plumbing, electrical, heating and cooling systems, insulation, smoke detectors, kitchen, bathrooms, foundation and understructure. He'll also tell you if the property satisfies health and safety codes.

- Pest control inspector. Temperate climates are a two-edged sword. While the people who live in these balmy, warm areas love the climate, so do a host of wood destroying insects and organisms. Since your contractor doesn't cover this problem area, you need a pest control inspector on your team.

- Architect. An architect's inspection is a must if you plan to do a major renovation of the property. Real estate agents aren't trained to estimate the time and money required to do big jobs like adding a room or installing a kitchen and bathrooms. Your architect can tell you if what you want to do is structurally possible, as well as give you time and cost estimates for the work.

Your agent or broker is the best referral source for property inspectors because they constantly work with inspectors. Ask your agent for a list of reputable contractors and pest control inspectors. You'll find inspection fees don't vary much from firm to firm for a standard job.

Be sure the property inspectors you select have been licensed by the state. This ensures that your contractor and pest control inspector passed the state's competency exam and that they meet the state's bonding requirements.

Your agent or broker may be able to recommend several good architects. Other referral sources might be your local chapter of the American Institute of Architects and friends who have used an architect to remodel their homes.

You'll make the best use of your property inspectors if you follow these rules:

- Always make your offer to purchase a property subject to your review and approval of the inspection reports.

- Whether you're a buyer or a seller, you should be present during the property inspection. Reading the report is no substitute for actually seeing the problem. Nor can reports answer additional questions you have about defects discovered during the inspection.

- Always get several competitive bids to do the corrective work indicated in your property inspection reports. Quotes for repairs will be much lower when firms know they're competing for your job.

- Never try to save money by having an unlicensed contractor do corrective work without permits.