Once home owners realize that termites have invaded, the damage is usually already done. Preventative maintenance is the key.

Termites cause an estimated $5 billion in property damage a year in the United States, according to the National Pest Management Foundation, making these pesky insects even more of a threat to wood-based structures than fire, flood, or wind.

Yet, many home owners know very little about the danger that termites pose to their property.

You don't usually notice them until the damage is extensive, says entomologist Ron Harrison, technical director for Orkin Inc.

Termites may take up residence in a home for years-even decades-eating away at the structure from the inside out (an average subterranean termite colony can consume a two-by-four per year) until the damage finally shows itself-hence the unsettling nickname silent destroyers.

Harrison knows of situations in which home owners have leaned against a wall and suddenly fallen through and toilets have plummeted through chewed-up floorboards.

Termites can enter a home by slipping through a crack in the foundation as thin as an average business card, Harrison says. Window vents and roof joints are also popular entry points.

Older houses, where it's more likely that the foundation may have cracked, probably are more inclined to be at risk. But new homes aren't off the hook: If termite pretreatments during construction aren't done correctly by the builder, termite swarms can take hold even after five years, Harrison says.

So how can home owners keep these crawly insects from biting into their investment? Harrison offers these preventative measures:

  • Keep moisture out. Use downspouts and gutters to divert water away from the home's foundation.
  •  Store mulch, firewood, and wood chips away from the home.
  •  Ensure shrubs, vines, and other plants aren't planted too close to the home and aren't covering vents.
  •  Ventilate crawl spaces to reduce humidity.
  •  Eliminate gaps and cracks in areas such as attic vents, window joints, and roof eaves.
  •  Remove old tree stumps and roots near the home.

A home owner's best defense is to schedule regular inspections with a termite specialist. The National Pest Management Association has a list of certified professionals on its Web site, www.pestworld.org. Termite specialists also can help prevent termites by using special wood treatments and repellants. Such treatments are usually needed every seven to 10 years, Harrison says.

Buyers would be smart to investigate whether the sellers already have a termite protection program in place. And, even if it's not required by the state or lender, you might recommend a separate termite inspection-especially in states where termites are most prevalent. While termite inspections are included in most standard home inspections, not all home inspectors are experts in this area and could miss the signs, Harrison says.

The FHA requires termite inspections only if there's suspicion of damage, if state or local laws mandate it, or at the lender's discretion. The U.S. Department of Housing and Urban Development's Web site provides information by state about areas most prone to termite damage (go to www.hud.gov and search for Termite Infestation Probability Zones). Because termites thrive in warm climates, activity is greatest in the South, Southeast, West, and Southwest. But many states in the Midwest, East Coast, and Mid-Atlantic areas also are deemed to have a high risk.

Even in areas with a lower probability of infestation, the right combination of food, moisture, and warmth can spell trouble. The bottom line: You don't want termites to eat up your investment, Harrison says.


Spot the Intruder

There are two major types of termites in the United States.

  • Subterranean termites are considered to be the most widespread and destructive termite species. They live in underground colonies or in moist secluded areas above ground that can contain up to 2 million members. They're found in every state except for Alaska, and they can produce swarms of hundreds of thousands of insects, usually in spring. Wood damaged by subterranean termites has a honeycombed appearance.
  • Drywood termites live in dry wood, such as in attics and crawlspaces, and do not need contact with soil to survive. They can be found in a home's framing, furniture, and even the hardwood flooring of homes. They form colonies of up to 2,500 members, and produce relatively small swarms of 10 to 100 insects-making them easy to go unnoticed. Wood consumed by drywood termites appears very clean and smooth.


Sources: National Pest Management Association and Termites101.org.