Okay, I recently made a house that had some heavily altered stairs. Since then, people have asked for a tutorial and I have helped a few others with their stair problems as well. Plasticbox has an awesome tutorial on split level stairs and I was directing people there. However, it doesn't cover the process on foundations. So, this is exactly what this tutorial tells you how to do. How to make split level stairs...on a foundation! As some additional information, this also works in TS2 as well!