Protecting Your Home From Termites
There are four major varieties of termites in the United States--subterranean, drywood, dampwood and powderpost. The subterranean termite is found in all 50 states and is responsible for about 95% of all termite damage. Drywood termites are next in line of destruction.
Subterraneans require regular contact with moisture, and thus must stay in contact with soil. This requirement limits their attack on wooden structures to wet and dry woods within reach of the soil. They construct distinctive earthen tubes to bridge the distance between soil and susceptible wood.
These tunnels, which protect the termite from would-be predators or from drying out as they travel from the soil to the wood in your home, are frequently found along the interior of foundation walls or can even be free-standing in the crawl space below the home.
Drywood termites, found in southern and coastal areas, don’t require the amount of moisture that subterranean termites do. They attack a structure at points far removed from the soil or foundation. After entering wood through a crack, the drywood termite excavates a small gallery and plugs the entrance with partially chewed wood and a cement-like secretion. Piles of the sawdust-like pellets are distinctive signs that drywood termites are present.
Frequently, the conditions that invite wood-damaging organisms can be discovered and corrected before the pests have made themselves at home. Therefore, it’s important for the homeowner to take measures that will protect the home from attack.
One major cause of damage by termites is poor home maintenance. Loose or cracked siding or stucco, peeling paint and gaps at trim around window and doors allow moisture to make its way into the home framing and provide an attractive environment for termites.
Cracks in stucco and gaps in siding should be repaired with an exterior-grade caulking or spackling compound. Peeling paint should be removed by scraping, pressure washing or sanding, and all exposed wood and stucco should be properly primed and painted. Areas of the home with the greatest exposure to sun and rain may require more frequent maintenance.
Low foundation walls that allow close earth-to-wood contact are a prime source for termites. Foundation walls should be raised or the earth lowered to a minimum of six inches and preferably eight inches. Cracks in foundation walls that offer access to wood should be repaired. The gaps at delaminating brick veneers provide easy access to the wood sheathing or framing below. Caulk these gaps to provide a weather-tight connection.
Poor ventilation in the crawl space will foster dampness and create an optimum environment for termites. It can result from a lack of crawl space vents or blocked vents. Thick shrubbery also can inhibit proper ventilation.
Correct the condition by thinning shrubbery, removing obstructions at existing foundation vents and, if necessary, cutting in additional foundation vents. A good rule of thumb for crawl-space ventilation is about two square feet of opening for every 25 lineal feet of wall.
Pieces of wood or cellulose debris under the house are tasty tidbits for termites and can help support a termite colony until the population grows large enough to attack the house. Use a flashlight or drop light to inspect the crawl space and remove any debris that may exist.
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Rotting tree stumps and damp firewood are other prime sources of food for termites. Old stumps should be removed and firewood should be stored on uprights at an area away from the home.
Porches, decks and wooden steps should never be in direct contact with soil. The base of steps should be constructed of redwood or pressure-treated wood that rests on a concrete footing. Deck-framing material should maintain a minimum clearance of eight inches from soil with support posts on concrete piers. A trellis, which is constructed with posts into soil and is connected to the house, provides a direct link for termites from soil to wood.
Planter boxes attached to the house are other culprits. They allow termites direct access to wood siding or to framing via cracks in stucco. Planter boxes should be supported below with metal or wood brackets and an air space of an inch or more should be maintained between the planter box and the structure.
Leaking pipes or water faucets keep wood or soil constantly moist and provide ideal conditions for termites. A simple way to check for leaks is to turn off all faucets and appliances that use water, including the ice maker. Next, expose the water-meter gauge and clean the glass covering with a soft cloth. Mark the location of the dial on the glass with a felt pen. Don’t use water for a couple of hours. If the dial has moved, you have a leak.
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Leaking pipes aren’t the only source of damp soil. Over-watered landscape surrounding the house, damaged or nonexistent gutters and downspouts that discharge near the perimeter of the home all help to create an environment that breeds termites. Drainage should be directed away from the house.
Special attention to maintenance should be given to the kitchen, laundry and bathrooms. The wall covering surrounding tubs and showers should be impervious to water and in good condition. Cracked tile should be replaced and grout should be renewed periodically to avoid leakage. Dried or brittle caulking should be removed and replaced.
Floor coverings should be in good condition. Floor coverings that are worn and expose the wood substrate should be replaced. Seams at vinyl flooring should be flat and solidly attached. The joint where a vinyl floor joins a tub or shower pan is an especially vulnerable spot and should be properly caulked.
To treat a home to prevent termite infestation can be costly--ranging from a few hundred to thousands of dollars. The traditional treatments of pesticides known to be toxic to humans are growing less popular. Consumers are exploring less-toxic alternatives.
