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Marin IJ Articles

How to detect, avoid termite trouble in your home

  • Martha Proctor
  • It’s estimated that more than one in five homes in urban areas of most Northern California cities have been or will be attacked by Western subterranean termites. These voracious insects are highly destructive to Douglas fir and other common building timbers widely used in the construction of homes here. They are known to enter buildings through cracks in concrete flooring or to travel under parquetry or tile flooring through gaps of less than 1/16-inch wide.

    Often confused with ants, termites are small, soft-bodied insects with straight antenna (not bent as in ants) whose waists are thicker than those of ants. They are usually pale colored, and all species have winged and wingless forms. All termites live in colonies in the ground or in wood.

    The three major types of termites common in California are dampwood, drywood and subterranean. Dampwood termites nest in moist wood and soil; drywood nest above ground in dry wood and subterranean termites, the most common type here, live under ground. Subterranean termites build nests in soil and dig tunnels to gain access to the wood or paper in your home. Subterranean termite workers are a creamy translucent color, about 1/8-inch long and wingless. Reproductives are dark-colored and have two pairs of equally sized wings. Wood blisters, discarded wings or termite waste that looks like sawdust on windowsills or floors are indicators of their presence.


    Because the diet of termites consists solely of wood and wood products, they are among the pests most feared by homeowners, particularly those of us in Marin who live in wooden houses. Termites cause billions of dollars of damage each year. They primarily feed on wood, but also damage paper, books, insulation and even swimming pool liners and filtration systems. Termites can injure living trees and shrubs, but more often are a secondary invader of woody plants already in decline. While buildings may become infested at any time, termites are of particular importance when buying or selling a home since a termite inspection and infestation report is normally a condition of sale.

    If winged termites are seen emerging from the base of a foundation wall or adjoining porches and patios, there’s a good chance the house is infested and treatment may be warranted. Discovering winged termites indoors almost always indicates an infestation warranting treatment. Other signs of infestation are earthen (mud) tubes extending over foundation walls, support piers, sill plates, floor joists, etc. The mud tubes are typically about the diameter of a pencil, but sometimes can be thicker. Even if you see swarms of flying insects around your home, a careful inspection of the structure of your home by a professional is required to confirm an infestation.


    The best way to keep termites at bay is to enlist some preventative tactics. Keep a 12-inch barrier of smooth concrete, sand or other material between the soil surface and substructure wood beneath a building. When possible, choose termite-resistant wood for fences or other structures that must contact the soil. Remove wood piles, untreated fence posts and buried scrap wood near structures. Provide adequate ventilation to substructures and keep them dry. Immediately repair foundation cracks.

    If you suspect you have termites, call a professional. Most proven effective methods are for professional use only in California. Do-it-yourself treatments are generally not adequate to manage a termite infestation as each species requires different treatment. Even if you manage to kill the visible insects and close off the crack from which they entered, you’ll need an experienced termite inspector to detect and delimit the extent of termite damage. Oftentimes there will be no visible indication that the home is infested.

    The company you choose should be licensed by the Department of Agriculture or agency responsible for regulating termite control in the state. Membership in their state pest control association and/or National Pest Management Association suggest the company is an established one with access to technical and training information needed to do the job correctly. As with any service company, references are invaluable.