What should be checked after drilling is completed and before treatment around subslab heating ducts?

After drilling is completed around subslab heating ducts, it is essential to check if air is coming through the hole because this indicates the potential for ventilation and airflow issues. The presence of air suggests that there may be gaps or openings in the ductwork, which can lead to unwanted air leaks. This is critical to understand, as it can affect the effectiveness of the treatment plans for wood-destroying pests and ensure that any chemicals or barriers applied can effectively reach the targeted areas without being dissipated through unintended airflow.

In contrast, checking for water presence, duct insulation, and soil dryness, while relevant in different contexts, do not provide the same level of immediate insight into the integrity of the duct system or the potential for successful pest treatment. Therefore, evaluating for airflow directly relates to the operation's immediate needs and the broader implications for pest management in buildings with subslab heating systems.