Through what means do subterranean termites typically enter buildings?

Subterranean termites primarily enter buildings through untreated wood that comes into contact with the ground. These pests thrive in moist environments and often build mud tubes to reach structural wood above ground level. When untreated wood is in direct contact with soil, it provides the termites with both a food source and an entry point into the structure. This situation creates an ideal breeding ground for infestations, as the termites can easily establish a pathway into the building without facing significant barriers.

The other options represent less likely scenarios for termite entry. For example, while cracks in windows may allow for various pests to enter, termites specifically look for direct access to wood and moisture, making windows an unsuitable entry point. Treated wood structures are typically designed to resist termite damage, providing a barrier against these pests. Lastly, ventilation ducts may allow for airflow but do not present a direct connection to wood that termites require for nesting and feeding. Thus, untreated wood in contact with the ground is the most accurate representation of how subterranean termites gain access to buildings.