Termites 82

Subterranean termites 85

Inspection 88

Drywood termites 91

Control 91

Inspection 91

Formosan termites 92

Other wood-destroying insects 92

Carpenter ants 92

Powder-post beetles 94

Inspection 95

Rot 95

Inspection 97

Checkpoint summary 97

There are many types of wood-destroying insects-subterranean and dry-wood termites; carpenter ants; and powder-post beetles. The one that causes the most damage to residential structures in the United States is the subterranean termite.


Home buyers generally overreact after discovering a termite condition and on occasion lose interest in the house. Actually, the discovery of termite infestation should not be cause for alarm-concern, maybe, but certainly not alarm.

Termites work very slowly. It takes many years for termites to do serious damage to a house. A mature colony of 60,000 termites eats the equivalent of 2 to 4 feet of 2-by-4-inch board in one year. Some well-established termite colonies have been estimated to contain more than 2 million termites. A termite condition can be controlled through the application of chemical insecticides by constructing a chemical barrier in the soil around and beneath the house. Thus termites attempting to go through the termiticide-treated soil to reach the house are either killed or repelled.

Prior to the mid 1980s, the chemical most often used for termite treatment was chlordane. It had an effective life that often exceeded twenty-five years. However, because chlordane is considered a potential risk to human health, it was withdrawn from the U.S. market. Currently several different chemical termiticides are available for use by pest control operators for controlling a termite infestation. All of the chemicals are considered safe and have been found to be effective in the soil for periods of approximately 5 to 10 years.

Around 1995 the termite bait system came on the market for termite control. This system is an option for homeowners that don’t want to use a chemical barrier treatment for termite control. Termite baits are considerably less toxic than most liquid termiticides, which are introduced into the soil by the hundreds of gallons in order to effectively control a termite condition in a house. Baits, on the hand, deliver very small amounts of termiticides over a long period of time.

A bait system for termite control consists of installing plastic tubes or boxes in the ground at various locations around the house. Inside the tubes and boxes is a slow-acting poison combined with a termite food material such as paper or cardboard. Termite control depends on foraging termites finding the bait stations during their random search for a new food source, feeding on it, and carrying it back to the colony where the poisoned food is shared with other termites in the colony.

The length of time for termites to find the bait stations will vary considerably and depends on whether the stations are installed in the southern or northern states. It also seems to depend on whether the bait stations are installed in the spring or late summer. The time to locate the bait has been found to vary from as little as a day to as long as a year or more. Baiting to control a termite problem is a slow long-term solution, and it is not the recommended method to control a heavy infestation problem in a house.

In real estate transactions, if the house has a termite problem, a barrier treatment is the preferred control method rather than baiting. Successful control by baiting is a long-term commitment to frequent inspections and monitoring of the bait stations and rebaiting. In contrast, when necessary, a single application of a barrier treatment can be expected to last from 5 to 10 years after which retreatment may or may not be necessary.

A number of states have regulations requiring a termite inspection by a professional prior to, or as a condition of, the purchase agreement. The cost of this inspection is almost always paid by the seller. If your state has such a requirement, you should ask the seller or real estate agent to have the house inspected by a professional and have a report of the results sent to you. In many states (even in some that do not have a prepurchase termite inspection requirement), if a termite condition is found prior to the sale, the cost for correcting the condition (chemical treatment) is borne by the seller.

When termites are discovered, they should be exterminated professionally. However, because termites work slowly, termite-proofing the house need not be done immediately upon learning of an active infestation. Take your time and get two or three cost estimates from established termite-exterminating firms. After treating a house, most companies provide a one-year guarantee against reinfestation. The guarantee can often be extended annually for a fee, which covers inspection and retreatment if necessary. If the house had been treated previously for termites, find out if the owner has a guarantee and whether it can be transferred to you.

During an inspection, all exposed wood-framing members should be checked for structural deterioration from termite activity. There are very few houses on record that have been damaged by termites to a point where they are considered unsafe. Quite often the damage caused by termites (by the time termite activity is discovered) is minor, and repair or replacement of the infested wood members is not necessary. Even with a heavy infestation, usually only a portion of the house is affected. And even then, only a portion of the wood framing might be damaged to a point where it has lost its structural value. In this case, only the affected members require repair or replacement. If you are in doubt about the structural integrity of any of the affected members, you should consult a professional.

NOTE: Lines defining areas are approximate only- see local FHA offices for specific areas-local conditions may be more or less severe than indicated by region classification.


Alaska is considered in region no. 4, Hawaii and Puerto Rico in region no. 1.


Fig. 8-1. Subterranean termite distribution in the United States.

Region no. 1  very heavy Region no. 3 Region no. 4 Region no. 2 slight to moderate moderate to none moderate to heavy

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