Spare Slates?

If you have some slates from the roof spare, line them up in a row against the side of your house and once a week during the warmer months, sprinkle some ant powder behind them.

This will eliminate the insects that get into you house and control the outside area next to the house where you most probably sit.

For me this also protect dripping rain falling off the roof where the gutter leaks and stops the dampness at the bottom of the outside wall.