Great Stuff makes an insect and pest resistant foam, I don’t think it’s specifically to keep ants out, but ants are opportunists…IME… if you make it easier to go somewhere else, they usually do.

Don’t do any of this, if you want to properly stop your infestation have to take a few measures. First follow the ant trails and see where the nests are. Second trim back any vegetation making contact with the home back and remove any hoses or other items that may be touching the home. Third, get an insecticide that the ants cannot sense; Termidor SC, Taurus SC, or Phantom will work. Phantom comes pre-mixed the others (original and generic) don’t and those will need mixed for perimeter spray with a 0.06% dilution. Spray the perimeter of the home with an “SC” spray…do not spray flowers or anything bees interact with…about 2 feet out and two feet up during peak ant movement time. Lastly if you found the nest hit it with Phantom.

Now, you’ve forced the ants to move through the insecticide they cannot sense. If they sense a insecticide the colonies get stressed and can split creating multiple new colonies for you to contended with. In two to three days ALL of the offending ants from the offending colony(ies) will die. The SC products use “fipronil” the same chemical found in frontline for cats/dogs. Members of the colony pick it up as they move over it…then as they go to their near they die and as other colony members touch the dead they die and soon the whole colony and every ant in your house is dead or dying.

Once these guys are dead, fix any holes. If it’s concrete then use hydrating cement or epoxy…if it’s wood just cut a place for you to put new wood and seal it up. You’ll never see another health and in your home again.