This is a viewer that has pavement ants where the concrete foundation and wooden structure of the house meet. They say it is difficult to get a granular control in there in the basement. How can they kill them?
The way it sounds to me the insects are outside, not on the inside- but I heard basement, too. It would be important to know what kind of ants these are. The ants that tend to swarm right now, that have a real lemony smell when you disturb them, are foundation ants. They're also called citronella or yellow ants.
Pavement ants often will nest in crevices, just like described and have a little bit of a mound. And they can be a little problematic. But pavement ants will take bait. They're smaller and brownish.
It's important to know the species. If you clear out those crevices where the nesting is occurring and apply boric acid powder or dust down in that crevice quite liberally it will kill them. Boric acid is not an insecticide, but it's definitely something that kills insects. It's absorbed by their bodies and kills them. That's the "green" method to use, so give it a try. A spray is also a possibility too; a complete drenching. But give the boric acid powder a try.