YES, we had the same problem. When we bought this house we found that the roof space ws lined with polystyrene insulation sheets and millions of ants had set up house in them....and laid eggs there too! We took it all down and lined the roof with plasterboard backed with tar paper, which the builders insisted would work. Now we have ants in between the roof tiles and the ceiling plasterboard and ant 'muck' - never live ones - drops down any holes. I have plastered up all the holes I can find and have now decided that is enough and I just hoover up any little bits that drop down. I know they are living in the roof like all our french neighbours' houses but as long as they dont come into the house I am OK with this and just spray the odd one that comes in the door. Finding the motor way up the outside walls to the roof isnt easy and the jell stuff wont stay on vertical surfaces....all part of the fun of hot france.