Considering that Massachusetts and most other northeastern states are located in a geographic region where termite pest activity is categorized as “moderate to heavy,” it may come as a shock to learn that termite infestations were once relatively rare there. However, as central heating became more common in northern homes during the first half of the 20th century, so did termite infestations. Indoor heating began to attract subterranean termite pests toward homes, and urban expansion into wooded areas where subterranean termites dwell naturally only compounded termite pest issues during this time.
In response to the increase in structural termite infestations in the northeast, housing authorities enacted building regulations that aimed to make homes less vulnerable to termite attacks. For example, one of these laws prohibited the structural and exterior wood on homes from making contact with the ground soil where subterranean termites could easily initiate infestations. This is why modern homes are built atop brick or concrete foundations, and wooden decks must be elevated several inches above the ground by concrete blocks. While these anti-termite building codes successfully reduced termite infestation rates, they did not make homes impervious to the crafty insect pests.
Modern concrete slab foundations were intended to serve as a barrier to keep termites at a safe distance from homes. However, termites are still able to infest slab homes by emerging from the narrow space between a home’s foundation and the surrounding concrete slab. This space is known as an expansion joint, and since subterranean termites can squeeze through cracks as narrow as 1/16th of an inch in width, they have no problem passing through expansion joints. As homes age, expansion joints become wider, and termites can also fit through the narrow cracks that form in concrete slabs as they settle into the ground. This explains why subterranean termite infestations are most common in older homes. A cork-like material is sometimes used to fill expansion joints, but termites can easily chew through this material.
Since subterranean termites cannot tolerate the dry outside air, they construct protective “mud tubes” that protrude through expansion joints or cracks where they lead into indoor structural wood sources by squeezing through narrow rifts in brick or concrete foundations. These mud tubes provide subterranean termites with a direct connection between indoor structural wood and the moist ground soil where they hydrate as needed. This is why subterranean termite infestations are usually located at the base of a home’s timber frame, and the presence of these vertical mud tubes along a home’s foundation serve as a sure sign that termites have established an indoor infestation.
Is your home built on a concrete slab foundation?