it's more than just stability, the reason I want the retaining walls, it's also so I don't have to mow there! It is dangerous and very difficult to mow that section. The hill is so steep. I want to have three tiers, with the terrain flat on each section, and plant something that will aid in soil stability like liriope, or any other kind of good soil stability plants. Just something I don't have to mow! I'm going to try and take more pictures tomorrow morning to show everyone what I'm working with. This thread has kind of gotten off topic, but it kind of ties in to my original concerns with the foundation and sloped floor sections.