Subterranean termites dwell in moist soil beneath the ground surface where workers forage away from their colony nesting sites. Generally, subterranean termites feed on natural sources of rotting and woody plant debris, such as dead roots, twigs, and bark. Occasionally, however, subterranean termite workers stumble upon timber-framed homes that offer enough wood to feed numerous generations of subterranean termite pests. Due to their high-moisture habitat within ground soil, subterranean termites are highly dependent on moist conditions in order to survive, and it is for this reason that the destructive insect pests favor damp and decayed structural wood over sound and dry structural wood as a food source.

Many homeowners may assume that the structural lumber components that make up their home have not become compromised by moisture saturation, but it does not take much moisture absorption to make structural wood vulnerable to subterranean termite attacks. Naturally, subterranean termites will readily feed on structural lumber that has become directly exposed to free water as a result of plumbing or rainwater leaks, but exposure to a few years of air humidity is enough to make structural wood vulnerable to subterranean termite attacks. This is especially true in Louisiana and other subtropical southeastern states where humidity levels are excessively high year round.

Of all areas within a home, the structural lumber components that become saturated with moisture most rapidly include columns, support piers, floor joists, beams, and subflooring within crawl spaces. This is because evaporating ground water becomes trapped within crawl spaces where it builds up and absorbs into structural wood. Spreading a plastic or vinyl sheet over the ground soil in crawl spaces will minimize the amount of water vapor that rises into structural lumber components. In order to maintain proper ventilation, vegetation should not obstruct crawl space openings, but ventilation alone is not sufficient to protect a home from subterranean termite infestations, as outside air is also quite humid. However, using a dehumidifier to maintain a relative humidity level between 55 and 65 percent is ideal for preventing wood in crawl spaces and other indoor areas from becoming vulnerable to subterranean termite infestations.

Have you taken measures to reduce the relative humidity in your crawl space?