Inside, ant nests are usually:

  • Underneath concrete slab floors.
  • Underneath showers and bathtubs (bath trap)
  • In foundation walls and basement floors. Especially on the wall shared with the driveway. Look around basement windows.
  • Near masonry or heat sources during late winter. For example, around the chimney or the floor near the furnace.
  • Look for ants or debris kicked out from the nest. This midden looks like miniature gravel with ant carcass particles in it.
  • Wooden support beams where it joins the top of the foundation.
  • If there is moisture between the sill plate and the foundation, you can see them there.
  • In a crawlspace attached to the basement.
  • In foam insulation.
  • Under doors, windows and in electric outlets.