Here we have an example of a fire ant colony moving from the yard into the house through a weep hole. Weep holes are gaps in the wall that are designed between the bricks to let moisture out. The ants can detect that moist air exiting the building and they go in. I broke the middle away so you can see the ants marching up into the wall. They build a nest up all the way too wall to preserve the moisture of their colony. They'll even move their egg sacs and all their entire colony back into the wall, putting pressure on your kitchens and bathrooms.