Termidor SC would work fantastic to put a barrier up outdoors.
Termidor is the # 1 choice for ant control around the home. Termidor is a non-repellent insecticide that works with a delayed reaction amd also has a transfer effect. That means that ants cannot tell that the Termidor is there and will walk right over it and then pick the product up on their bodies and inadvertently carry it back to the colony, then through normal social interaction the ants spread the Termidor and wipe out the colony. Termidor only needs to be applied two times per year and is effective for a wide variety of insects including ants, centipedes, roaches, spiders, silverfish, wasps and many other nuisance insects. You will need to apply Termidor SC 1-2 ft up the foundation and 1-2 ft out onto the ground, around door frames, window frames, places where cables, pipes or wires go through the wall and any other crack or crevice where the ants can gain entry into your home. Indoors you can use
Phantom to treat cracks and crevices.