Since buying my house a few years ago, I've been fighting a losing battle with ant infestations in my outer wall. It has recently reached a head, since we found a nest inside of an electrical outlet adjacent to that wall.
There are actually two types of infestations (carpenter ants in wood, small ants behind a brick facade), but I have the same questions for both of them.
- Is it enough to kill the ants, or do I need to replace the wall material they were nesting in?
- If I do have to replace the wall material, do I need to clear out the ants first, or is it better to avoid spreading poison given that I'll be hiring someone to pull out that material?
Here's some more info. I'm in the Atlanta area.
Carpenter ants: These are in one of my window frames and the frame around my garage door. In some cases, I can see the holes that they used. When I first moved in, I drove them off with a spray made from plant extracts. I removed vegetation that was anywhere near these nests. I did not attempt to repair/seal the wood they were in. It seemed to work for a couple of years, but now they are back. One of these colonies is now using my interior windowsill as a waste dump/cemetery, but otherwise I don't see them in the house. We called a pest control company a year ago, but they were worthless. They were not interested in inspecting the wall at all, and just put some poison around the house which did nothing to control the ants. This year I've used Combat insecticide gel (outside the window), and it seems to have brought their numbers down but not eliminated them.
Small ants: As I walk around my house I frequently will see one or two lines of ants marching into my wall (going up from the ground and disappearing under my siding). I do not see them inside the house, and it looks like they are carrying food into the wall, so I think they are nesting in the wall and foraging in the yard. This is worst where I have a brick facade (~3ft tall) instead of siding. I see them entering and leaving the bricks through multiple openings just a few feet apart. There are some medium-sized bushes near here (with about 1 ft clearance between the bush and the wall). These ants are not too interested in the Combat gel that I put out. On the interior side of this wall is where we found the nest in the electrical outlet. It smelled like mold. I applied some Terro bait in this area, and the ants were not very interested in that either.
So, is it enough to eliminate the colonies, or will a new colony just resettle the same part of the wall next year?