My parents have a two-story house in Michigan. They have a carpenter ant (large black ants) problem in-between the first and second floor. A couple weeks ago a plumber was in the second floor bath to replace a leaking toilet seal. When the toilet was removed, a large mass of ants fell out from under the toilet – it was a huge party…drinks and munchies were (on) the house. Evidently, they had crawled up through the rotted area around the toilet drainpipe. A lethal dose of RAID! was administered. The problem – carpenter ants continue to appear on the first floor. Any suggestions on how to extract all the ants without a full house fumigation or removing the first floor ceiling drywall? A small section of drywall on the first floor below the leaking toilet was removed (water damaged), but there are no signs of ants here. (Limitations – my mother has outlawed the further use of RAID or similar chemicals)
You need to remove all infested material or pinpoint treat infested areas and have professional perimter treatments of the home. If possible locate the parent colony (usually within a hundred feet of the home) and treat it. Fumigation is not effective. What you are seeing is probably satellite colonies from outside the home.