Q. We have stacked firewood at the back door of our house and the wood seems to be full of big, black ants. I’ve told my husband that he needs to move that woodpile away from the house because the ants could get inside. Could these be carpenter ants and what are the chances that they would move into the house and do damage?
A. They could indeed be carpenter ants. Carpenter ants are our largest ants. A woodpile, especially if it’s sitting directly on the ground, would be a typical nest site for carpenter ants. Carpenter ants like wood that is damp and softened. They don’t actually feed on the wood like termites do, but they hollow it out for nest sites.
We tell our customers not to store wood right up against the house because firewood can contain termites and carpenter ants and a number of other wood borers and nuisance pests. All insects meander around looking for food, hiding places, and nest sites. If they find conditions that they like, or an opening into your home, they could investigate. Having said that though, as long as the ants have that wood pile for a nest site and plenty of food in the form of insects, they are probably pretty content where they are.
I would be concerned though if you have any areas nearby on your home that may have water damage from a plumbing leak, roof leak, or drainage problem. Maybe your back deck or stoop has some water-damaged wood. Carpenter ants usually first infest homes in these locations where the wood has been softened or is decaying. They can then move their nests from water-damaged wood into perfectly sound wood.
In fall, when their insect prey are dying off, carpenter ants may become more desperate in their search for food and may be more likely to forage indoors. By the way, seeing carpenter ants inside your home doesn’t necessarily mean they are nesting there. They could just be trailing inside to get food while nesting outside. You would need a professional inspection to find out.
Your husband should still move that firewood away from the house. Or, maybe he needs to just burn it (outside). I’m guessing it may be old wood that has been sitting there for some time and is in pretty poor condition anyway. If it’s heavily infested with ants it may not be worth saving. Don’t try to treat the wood with pesticide to kill the ants. The pesticide won’t reach them inside the wood and it’s dangerous to burn treated wood afterwards. In the future, firewood should be stacked up off the ground and away from the house.