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.