Subterranean termites are the most widespread
and destructive termite group in
North America. They are so-named because
they excavate through the soil to reach
wood in contact
with the ground.
To reach material
above ground, they either move through connecting
wood, or through earthen "shelter tubes" that
they build over concrete, masonry, or other materials.
Given the choice, subterranean termites will
usually access aboveground wood through protected
cracks and cavities, such as in concrete slabs
and foundations.
Subterranean termites normally return to the soil
periodically for moisture. However, if the moisture
content of wood above ground level is high enough,
they can survive and multiply indefinitely with no
ground contact.
Eliminating conditions favorable to termites is an
essential first step