Exactly what Hajo said, you have wet wood somewhere that is attracting the ants. Do yourself a favor and go around the 4 corners of your home and look closely......you may actually see what looks like sawdust, that will give you a hint as to where the colony is..... Seal up any entry into the home thats big enough for an ant to enter thru, expecially where the homes framing meets the foundation. If you have a basement check the pockets between the 1st floor....floor joists, they love to live behind the insulation in those pockets.( regarding filling in areas, Dont fill in areas that are ment to allow airflow into the structure, your home does need to breath or it will rot ) I fight the battle every year with them, and find the liquid baits work best.
As a property insurance adjuster, ive seen thousands to tens of thousands of dollars of damages done by these ants......An exterminator may be a good investment