I would wonder if the bats will still find a way to get on the other side of that screening. As previously mentioned, they can get through the tiniest of spaces--I've heard a comparison to a dime. I have no solution for your situation but hope you can find some sort of repellent that they would choose to hang from another location. If they are in the carport, they can easily get into the house when the door opens----ewwww. Somehow they never seem to find the door going out!