Guest post provided by Landscape East & West, an award winning full-service landscape and design company based in Portland, OR.Retaining walls are a popular landscape feature worldwide and are commonly used in the Pacific Northwest because of the wet weather, fault lines and hilly terrain. Unlike ornamental garden walls you may find in terrace gardens, an effective retaining wall design serves an important purpose – to hold soil back. Of course, if you are going to incorporate a retaining wall into your landscaping, it might as well look attractive.
Determining the Need for a Retaining WallBefore spending the money to build a retaining wall, it’s wise to know if such a project is necessary. You may benefit from the addition of a retaining wall if any of the following conditions apply:
A sliding hill threatens your foundation.If your home is on a sloped foundation, erosion can threaten its structural integrity. A retaining wall will help control the movement of the soil around your home.
You want to control erosion.If your property is the landing area for erosion materials, a retaining wall can help redirect the materials as well as the flow of water.
The home is downhill from a soil fault line.Even if erosion isn’t presently a concern, it can be if there is an earthquake because the earth generally slides away from a fault line. The addition of a retaining wall can help give your home the barrier it needs to keep it safe during a seismic event.
The Function of Your YardBefore you incorporate a retaining wall into your landscape, you’ll need to determine the desired function of your yard. For example, a landscape can serve as a:
- Private, outdoor living space
- Space for multiple garden rooms or themed gardens
- Spot for entertaining
- Creating a flat area
- Creating a dedicated space for a water feature, themed garden or outdoor living space
- Privacy screen
Retaining Wall Design BasicsResidential landscape architects generally don’t build retaining walls that are taller than 4 feet because the depth of the footing increases with the wall’s height, and because many cities require special permits for taller walls. For safety reasons, architects take into account the scale of the project, the types of soil on your property and drainage solutions, as well as the elevation and slope of the earth behind and in front of a wall. The primary concern when building a retaining wall is its structural integrity; cost and aesthetics are secondary.
Retaining Wall MaterialsTo choose the right building materials for your landscape, consider the design aspects you use inside your home, and skim through pictures of existing retaining walls to help you decide on the desired look of your wall. Popular materials you can use for a retaining wall include:
- Plain or decorative concrete blocks
- Poured concrete
- Dry-laid stone
- Mortared stone
- Treated lumber