What is caulking or filling in cracks in buildings and foundations primarily used for?

Caulking or filling in cracks in buildings and foundations is primarily used as a method of pest exclusion. When openings and gaps are sealed, it prevents pests like insects and rodents from entering the structure. This physical barrier is essential in an integrated pest management strategy, as it minimizes the opportunities for pests to gain access to food, water, and shelter within a building.

While it can help with thermal insulation to some extent, that is not its primary purpose in pest management. Similarly, although minimizing pest entry is crucial, it does not guarantee that all pests will be kept out. Finally, although it may be part of a treatment plan, it is not specifically the last step; rather, it should be an ongoing part of maintaining a pest-free environment. Thus, the primary function of caulking in this context is to enhance pest exclusion.