For which foundation depth is trenching best suited?

Trenching is most effective at a foundation depth of no more than 12 to 15 inches below grade. This depth allows for easier access to the foundation area where treatments for termites and wood-destroying insects can be performed without excessive intrusion into the soil or the structure itself. When trenches are dug within this range, pest control professionals can effectively apply necessary chemical treatments directly into the soil where termites are likely to be active.

Deeper trenches, such as those that are more than 18 inches below grade or in the range of 18 to 24 inches, would pose challenges for treatment application and potentially lead to complications in addressing infestations effectively. Similarly, a trench less than 6 inches below grade may not reach the necessary soil layers where termites typically reside, making it insufficient for effective pest management purposes. Thus, the specified depth of no more than 12 to 15 inches aligns perfectly with the practical requirements for effective trenching in pest control scenarios.