One side/corner of my house seems to have the earth under the slab eroding away. The gap is almost 2" in one place now, I can reach in and grab gravel stones which I assume that the slab was poured over. I need to stick a yardstick in there and see how deep it goes, but haven't done that yet. It could be that that these stones were added as fill by the previous owner who tried to patch the gap. The slab around and above this area has a few cracks in it too. A drafty cold air can be felt inside the house opposite from this area. The house has been slowly settling, proof can be seen where the gas pipe enters the house, and the fact that the settling caused the gas pipe to rupture 3 years ago. When I had that repaired I had them allow for some additional settling by caulking the heck out of the opening rather then cutting the siding exactly around the opening. Now you can see that the spot at the repair has settled a bit...hopefully not stressing that pipe too much. My current ideas are: 0. re-re-re-ensure that water is draining away from the house 1. chip out all remnants of previous quickcrete/expanding foam repair job and re-apply 2. contact professional for an estimate and advice Any other ideas or experiences?