All termite species are social insects that live in colonies, but unlike single-nesting drywood termites that only inhabit above ground wood in southern states, subterranean termites live within moist ground soil where a single mature colony is typically composed of multiple interconnected nests. With the exception of the original nest established by the queen and king during swarming season, all nests associated with mature colonies are secondary nests established by workers to mark the expansion of their colony’s foraging range. Amazingly, researchers have uncovered subterranean termite colonies that span 400 square feet in land area.
Although the eastern subterranean termite (Reticulitermes flavipes) is the only termite pest species found in Massachusetts, it is the most destructive structural pest in the country. This species’ abundant presence in suburban and urban areas of Massachusetts is why it’s one of the few northern states where termite pest activity is deemed “moderate to heavy” by the US Department of Agriculture. Since subterranean termites remain within moist soil at all times, foraging workers establish infestations almost exclusively within substructural lumber components located within the foundation walls. Workers will readily eat into structural lumber that is in contact with their ground soil habitat, but accessing above ground wood is a little more challenging for the pests. Modern residential building codes require all new homes to be built with termite-resistant structural features. For example, the lowest structural wood components within a home must be elevated 18 inches above the ground to prevent subterranean termite workers from accessing the timber frame.
Pre-code homes that lack a brick or cement foundation between substructural wood and the ground surface must occasionally be altered to avoid subterranean termite attacks. This usually entails the excavation of dirt until a space of 12 to 18 inches exists between the ground surface and base of a home’s timber frame. Once this task is complete, each foundation wall must allow air to flow into the crawl space to prevent moisture buildup that attracts subterranean termites. This involves properly placed square openings at least as large as 2 square feet on each foundation wall. To maximize air flow, vegetation should never grow in front of ventilation openings on foundation walls, and in humid areas where soil is relatively moist, a vinyl sheet is often placed on the ground within crawl spaces to prevent water vapor from saturating substructural wood components.
Have you considered installing a vapor barrier over the ground surface within your home’s crawl space?