Termites play an important ecological role because they decompose wood and other plant materials containing cellulose with the aid of gut microflora. Rarely noticed because they live underground or within wood, termites become problems when they invade structures. The U.S. Department of Agriculture estimates annual termite control costs at about $2 billion. Treatment costs depend on the type of termite, extent of damage and structure size, and whether you can do it yourself or need a professional.
Colonies live in wood and are difficult to detect and evaluate. The University of California Integrated Pest Management Program doesn't advise do-it-yourself treatments for drywood termites. Control means treating the infested wood. For extensive infestations, an impermeable tent encloses the whole structure for fumigation with a toxic gas. Costs go from $1,200 to $2,500 for a 1,250-square-foot home and increase with the size of the structure, up to $3,800 for a house with 2,500 square feet. Other costs may include staying at a motel while fumigation occurs and replacing damaged wood. Whole-house heat extermination is quicker and costs about $1 per square foot; however, it can damage heat-sensitive household items. For small infestations, localized treatments using microwaves or electrocution cost about $1,150. Chemical liquids and dusts can be applied to infected wood, with cost depending on the chemical used and the amount of wood treated.
Colonies of subterranean termites live underground and move from nests into structures. Treating infected wood won't destroy the colony. Control them with baits and insecticides. For professional application of chemical insecticide to the soil around your home, costs vary according to the competitive rates in your area. Termite MD considers an average price to be from $4 to $7.50 per linear foot, which is the total distance around the outside of your house. If you do the chemical treatment yourself, Termite MD estimates a cost of $.81 per linear foot. For professionally applied bait treatments where termites eat a toxic chemical and spread it through the colony, Termite HQ estimates a 20 percent greater cost than chemical treatment. Do-it-yourself termite baits cost about $100 a box, with most homes needing several boxes. Professional bait treatments are often over $1,000. However, cooperative extension departments of the University of Kentucky and Texas A&M University advise using professionals for effective bait control of termites.
Dampwood termites live in moist soil in the Southwest, southern Florida and along the Pacific Coast. Larger than subterranean termites, they have conspicuous workers with large heads and jaws. Control is with chemicals and baits, with costs similar to those for subterranean termites. You can also remove moisture sources or remove and replace infected wood, with costs depending on how much replacement is needed, the cost of the wood, and whether you do it yourself.
Using wood such as redwood or cedar that is resistant to termite damage in initial building construction or using chemically treated woods that are toxic to termites adds to construction costs but helps prevent infestations. Treat a foundation with insecticide before pouring a concrete slab at a cost of about 20 cents to 45 cents per square foot. After initial termite control treatments, exterminating companies often offer annual followups for about $100 to $200 per year.