If you frequently see ants in the same area on the siding there s probably a nest in there.
Ants behind vinyl siding.
The holes are often located between bricks where mortar has fallen out under lap siding or in cracks in stucco.
They burrow into it to make their nests so they leave behind a wood dust.
The problem with treating pests that lodge behind this shielding is that it gives you very little access to inject anything meaningful.
If you are leaving the siding off for a short period of time to dry out i would get a spray container and fill it with a bleach solution then spray the area.
Examine your foundation for cracks and tightly seal.
And you need to make sure you treat that with a strong insecticide.
Unlike termites carpenter ants do not actually eat wood.
As most of the posters said water or moisture is the reason they are there.
How to get rid of ants begin with looking for holes in the siding where ants are crawling in and out.
Earwigs roaches ants wasps and bees just to name a few often find your homes siding a perfect place where they can feel protected too.
If you have a serious carpenter ant problem you may find wood shavings underneath your siding.
Ants nesting in dead branches use the limbs as a bridge to the house.
Unfortunately it also gave cover and safe harborage to many pests.
If it can t be found once you pull the siding you ll need to find some other way to locate it and get the dust in there.
If winged ants come out of crevices around your home this is a strong sign that you have a serious ant problem.
If you notice the ants carting off their eggs then they are moving out.