You might think the answer is to seek a therapist, but not in this case.
Formed, poured-in-place concrete walls hold back the hillside and guide the visitor through the space in a San Francisco garden designed by Terremoto.
Photograph by David Godshall courtesy of Terremoto.
As the name implies, a retaining wall is a structure that retains mass behind it. The most basic purpose of a retaining wall is to battle, and one hopes, win against gravity and the forces of nature.
What is a retaining wall?
Photograph by Mark Darley and Stephen Wheeler, courtesy of Scott Lewis.
A modern retaining wall designed by landscape architect Scott Lewis is made of San Francisco ship ballast cobblestones (original to the circa-1912 garden).
Low retaining walls capped with zinc create perimeter planting beds in a Manhattan townhouse garden. Science lesson: In an earthquake, land typically slides away from fault lines and so a retaining wall provides necessary support.
When do I need a retaining wall?
Photograph by Francine Fleischer.
To create definition on a hill: Retaining walls can create terraces on slopes. To add seating: Design your retaining wall with a flat top to provide a usable place to sit.
On her sloped lot in Austin, Texas, landscape architect Christine Ten Eyck designed low retaining walls (using limestone rocks found on site) to create “check dams” to manage rainwater runoff.
Photograph by Matthew Williams for Gardenista.
Photograph courtesy of Matthew Cunningham Landscape Design.
Granite retaining walls direct water flow away from a circa-1916 house on Maine’s Mount Desert Island.
What are the best materials and styles for retaining walls?
A wood retaining wall painted with an eco stain for a modern look. There are variations on the wood theme such as timber and boards, and steel I-beam with boards.
Photograph by Kier Holmes.
A granite retaining wall “floats” in a lawn in Maine, providing overflow seating for guests at the clients’ frequent lobster feeds and clam bakes. Concrete blocks or poured concrete walls can be faced with stone or brick to give it a more specific look.
Photograph by Matthew Cunningham.
Photograph courtesy of Kettelkamp & Kettelkamp.
Gabion wall baskets are topped with caps of poured concrete. See Hardscaping 101: Gabion Walls for a complete look at this material option.
Are retaining walls a DIY project?
Being a total do-it-myselfer (is that even a word?) The double truth: if your wall is higher than 3 feet and your slope is steep, then I strongly recommend you hire a structural engineer, soils engineer, and a skilled contractor to do the design and installation.
Photograph by Kier Holmes.
Design Ideas for Retaining Walls:
Add a fence to your retaining wall for contrast of materials and additional privacy.
Photograph by Kier Holmes.
Design a water feature into your wall or face an existing retaining wall with horizontal boards.
Creeping fig (Ficus pumila) grows up a wall in Austin, Texas, in landscape architect Christine Ten Eyck’s garden.
Photograph by Matthew Williams for Gardenista.