N.
Hi Trish,
This may take a while, but if you follow them back to where they are coming from, i.e. a crack in the floorboard, or at window, and put a few drops of white glue (Elmers' etc) in that place, it will block their entry point. They may try find other ways in, but eventually they'll give up. I have had great success with this both inside and outside the house. The glue dries clear, so it won't show unless someone is really trying to find it. Good luck! N.