We have had a big problem this summer, they seem to be appearing from every tiny little crack, we have only lived in the house since March. We are getting it under control now, but are very continually vigilant. We cut down a very big geranium which was touching a back wall, put and powder bought from the cooperatives along every wall of the house, filled every tiny crack, ensure nothing on floors or work surfaces to attract them, lifted cat water and food every night and had ant spay on hand continually. The pods from mercadona are very good as they take the contents back to the nest and over a very short period of time kills them all. The proof of the pudding as they say will be when we return from holiday and fingers crossed the house will be ant free.