CAUSES OF FOUNDATION SETTLEMENT
Whether you live in Tulsa or OKC, ultimetly it comes down to; your home is sitting on many different layers of soil. I'm sure you can imagine that each layer has a different amount of structural integrity, being as they are made of different soil types. As the earth has developed, some of these were carried here by way of water, others were carried by wind, & some may have been brought in by the builder. As a rule; soil layers genereally get stronger with depth. Most commonly there is a shallow layer near the top that is organic. This is where plants and vegetation can grow. Below that top layer, you will find layers of sandy, silty, or clay soils. These are the unstable layers of soil. If you keep going you will eventually reach bedrock, which is very stable, dense soil. The goal for piering is to support your home from the bedrock; rather than having your house move around with the unstable soil types that it currently sits on.