The most common reason that slab houses move is because of expansive soil. The soil will swell up as it gets wet and shrink as it dries out.
The most common solution is to install piers. Our piers are installed to a depth of eight feet. At eight feet the moisture level in the soil is much more constant than at two or three feet. Their are many different types of piers on the market. Most are quick, easy and over priced. The surface area of the pier against the soil is what holds your house up. We use a double shafted pier, each shaft is 8 inches in diameter, where most use a single shafted pier that is 6 inches in diameter or less. Our competition would have to install twice as many of their piers to even come close to matching ours. Compare our pier and reputation and you will see that we are offering a permanent solution to your problem.