Barehunter, trying to picture a "portico", the drive thru helps my picture, but if you have a picture that would help. If I picture most type of areas, there are two things that fall under exclusion if they are serious that this is a major problem. If this is just a couple of bats I can't imagine a client being fired up enough about the few pellets of guano and the few drips of urine going to come down, most folks wouldn't know that was what hit their windshield.
But, if there are more or they are serious, I'd look at two options, you could use netting available from commercial suppliers and create a "drop ceiling" that is lower and doesn't give them the protected area that they like to linger in.
Or others have shown over time that using a slick surface installed including plexi sheeting, and you can paint match it to make it less cosmetically bothersome to the folks. The trick though is that any little build up of caulk, or bumpy texture they can stick to, so if you go down that road, remember you need to make it a smooth surface. Some bird suppliers sell the plexi strips for swallow nesting, so you can picture what I mean by thinking of deterring a swallow nest from happening on that 45 degree angle in the portico.
Let me know if this makes sense for the structure, like I say, trying to picture it.
I netted a porch with bat problems a few months ago and it is working great, bats are back in full swing and he has no issues, haven't ever tried the plexi but lots of other folks on here have and people I respect have had success with it.
All depends on client, cost, and structure.
Hope that helps,
Justin
