Slopes can create big challenges when building landscaping projects. Many structures, including sheds, walkways, gazebos, and patios, require flat surfaces. Even garden planting areas are much more effective if they are situated in flat areas of the yard. Retaining walls offer a way to create flat space for such projects.
There are two ways a retaining wall can be used to create flat space. To create a flat area in front of the wall, the process involves cutting back, or notching into the slope, then building a retaining wall to hold back the remaining hillside behind the wall. This is often the method used where the slope is quite steep.
Alternately, you can build the retaining wall, then fill in the space behind it. This method is often used on gentle slopes, where you want to interrupt the slope with a tier of flat garden or lawn.Retaining walls can create useful space from areas you once thought were unusable. If built properly, your retaining wall can last for many decades.
Retaining walls have structural requirements unlike that of any other landscape wall. Some garden walls aim at providing simple privacy, marking property lines, or keeping pets and children safely inside.
These can be built from cinderblocks or stacked stone—or they can be simple fences made from wood or vinyl. But a retaining wall must hold back the earth itself, which can exert thousands of pounds of force when saturated with water. The design of a retaining wall must anticipate those stresses.
For this reason, the space behind a retaining wall is usually filled not with soil, but with a porous, drainage-promoting material such as gravel or sand. Tall retaining walls may even build in a drain pipe or other features to shed water and lessen the pressure on the wall.