Can Ants Nest In Walls. Image via flickr by photochem_pa. Ants in walls are often a problem because it means there is an access point that is allowing them to get inside.
They can also nest in foam insulation.
But if those ants you see in the kitchen came from a colony inside your walls, that could be bad, especially if they are carpenter ants. Nesting ants that enter your house to forage for food aren't too much of a problem. Learn what to do about ant infestations in your walls. Following an individual ant back to its nest can be tedious.