my bet would be to call a certified pest control dealer. i know this is aggravating for you. just seeing a trail of ants in my kitchen is sickening enough. you can lure ants, too, with these little black plastic ant baits available off the shelf at most stores. place them in strategic corners and the ants go in, but do not come out.
true story: a skunk bored his way under a million dollar dwelling in upscale chicago suburb. he’d dug tunnels and sprayed continuously. the homeowners had to have the entire house gutted, drywall, carpet, floors and all. to get to the rascal, they contracted professionals dressed in what seemed to be hazardous materials gear, bore a hole through massive concrete of the front porch. the stinch was in the clothes—everything. the occupants had to leave their home and live somewhere else. the ordeal was so long and exhausting, it even led to divorce.
got skunk?