Stone retaining walls come in an endless array of shapes, sizes, styles and types. They can be purely decorative, or they can combine beauty and function by helping to level an area, support a sloping area, help with erosion control, break up a section of yard into smaller areas, create a garden area, and many more uses.
Common types of retaining walls include gravity, semi gravity, cantilevered, and counterfort. A gravity retaining wall relies on its weight to hold back the soil. These are constructed in a shallow cone shape with the base wider than the top. In some cases the wall is angles slightly back toward to help improve its stability. These types of walls can be made from dry stacked, mortarless stone although the height will be limited.
A semi gravity wall is essentially a gravity wall that has been reinforced with steel rods. These are a little stronger than pure gravity walls and need no additional reinforcement.
A cantilevered retaining wall has a base or footer that extends under the soil. Viewed from the end, a cantilevered wall has an L shape with the foot of the L buried underground. These walls can be thinner than a gravity wall and rely on using the weight of the soil on the footer to hold the wall in place.
Counterfort walls are similar to cantilevered walls except that they supports that tie the end of the footer to back of the wall. These supports are buried underground so counterfort walls look the same as cantilevered walls. If the supports are placed on the face of the wall where they would be visible, they are called buttresses.
Anything beyond a low, dry stacked gravity wall should be designed by an engineer. Otherwise you are risking potential serious injury due to collapse of the wall.
