 In terms of that sidewalk outside, you know, that's probably an asphalt sealant that was used between the sidewalk and the house. Just generally speaking on the outside of your house, make sure the water is draining away from the foundation. And if that sidewalk slab happens to pitch in to the house, that's a bad thing. No matter what you seal it with, you're not going to stop water from getting into that wall. So that would be a case where you'd have to either tear out the concrete and replace it, or depending on how it's built, sometimes you can lift that concrete one section at a time and actually repitch it.