Today we're going to be talking about caulking on the exterior of a building and the reasons why we would do it. If you look at the transition between this brick mold and this stucco siding, you can see there's a small little variety of gaps from top to bottom and we want to eliminate moisture intrusion. So in order to do that, we need to caulk a thin bead of caulk down this particular line so that we can seal up that issue