 Well, you're right. I mean, just about every home has its own share of cracks. They're a pretty common occurrence, and there are a number of reasons why they happen. So, for example, the soil may not have been compacted properly before the foundation was installed, or you could have large pieces of organic material that had been included in that soil under the house. Sometimes you'll have contractors that will leave tree stumps in, and when it decays, the soil above it collapses to fill the void, and then, of course, that leaves a gap under the foundation.