Termites are a concern for homeowners in every state except Alaska. These destructive insects can slowly destroy the structure of a home, eating the very wood it's made of and inflicting serious damage that can run into the tens of thousands of dollars, sometimes even requiring the destruction of the structure if the termites are allowed to stay unchecked. While termite eradication can be expensive, a few simple precautions can help prevent this; many of the typical preventive measures involve reducing or eliminating moisture and water near the foundations of the house.



The most common types of termites are the Formosan termite and the Eastern subterranean termite. Formosan termites, found chiefly in the Southern US, are subterranean termites that may nest either in the soil or in the wood of a structure. The brown reproductive termites swarm in the evening during May to July. Colonies of Formosan termites are large, with up to 5 million individuals. Therefore, they destroy wood faster than the Eastern subterranean termite. The more widespread Eastern subterranean termites live in smaller colonies and therefore tend to take longer to inflict damage. During the spring, the reproductives swarm and leave the colony. The reproductives are black and have a thick waist, their antennae are straight and both pairs of wings are the same length. These termites feed on wood, but nest in the soil, constructing mud tubes from their nests to the wood in structures.

Both of these varieties of termites depend on moisture for their sustenance, and build their nests in areas that have abundant moisture for their building and nourishment means. The pencil shaped tubes that they use to climb from the soil into the structure of a house are made of mud and must be kept moist, so eliminating excess moisture is crucial for termite prevention.

The first measure to implement is to remove any direct contact between structural or decorative wood and the ground. Any wood in contact with the earth tends to soak in moisture and become a magnet for the insects. Overhangs, decorative lattice work (typically used under porches and decks, and over the openings to crawl spaces), and support posts should be cut loose from the ground or given some kind of concrete footing, so that wood that has become moist from rain or run off does not attract termites.

Reducing and eliminating the water in the ground directly around the foundation is the next critical step. Putting in a slope to allow water to flow out from the house is crucial; homeowners should also consider the possibility of adding a concrete skirt around the foundation. Gutters and downspouts should be kept on good repair and adjusted to direct water as far out from the foundation as possible, and sources of dripping water such as air conditioners should be set up so that any standing puddles are eliminated. Splash blocks (which disperse water when it strikes the surface) are useful for this purpose.

While many homeowners use mulch, ground cover, and various forms of pea stone and gravel around their foundations for its beauty and practicality, these are an open invitation to termites. All of these substances serve to trap moisture and water under the surface, providing an ideal medium for termites. Mulch itself is not particularly attractive as a food substance to termites, but it holds water that attracts them. Contrary to popular belief, stone and gravel covers hold as much water under the ground as mulch, so this is not a useful alternative. If gravel or crushed stones are used, the cover should be no more than 2-3 inches deep, and there should be no contact between the gravel and the siding or wood components of the house.

Crawl spaces are prime staging ground for termites. Most building codes call for 1 square foot of vent opening per 150 square feet of crawlspace area. Moisture in crawl spaces can further be reduced by installing 4-6 ml polyethylene sheeting over about 75 percent of the soil surface. This cover will act as a barrier to evaporation from the soil and help prevent condensation of moisture on joists and sub flooring. If a crawlspace has a polyethylene vapor barrier, the total vent area often can be reduced to 1 square foot per 300 to 500 square feet of crawlspace area. There should be one vent within 3 feet of each exterior corner of the building. As with gutters and downspouts, vents should be kept free of leaves, dirt, and other debris, and should not be obstructed by vegetation. Although a homeowner can install these barriers themselves, it is not an easy job, and such vents and vapor barriers can be installed by most pest control companies.