Landscape architects use stone retaining walls and other hardscape features to define functional areas and to create connections between them. They may use multi-level patios, steps and walkways, for example, to finesse natural elevation changes on a site. Hardscaping and retaining walls give shape to the landscape overall and enhance its natural beauty.
Strictly speaking, a “retaining wall” is used to retain soil when it’s necessary to hold back a steep grade. However, we use walls of differing heights in landscaping to achieve various goals in service of the design intent. Aside from terracing slopes to create level areas on a site, we use retaining walls and freestanding walls for
- Bench seating in a gathering space
- Low borders along raised planting beds
- Defining outdoor rooms
- Privacy and security
Retaining Wall Construction Methods
1 Masonry block walls (our preferred method) require a poured concrete footer, cinder block, and natural stone veneer that is fixed to the block wall with mortar. We run rebar through the channels in the cinder block and fill them with concrete for reinforcement. The cinder block wall provides a rigid structure to support the natural stone facing which is purely decorative and has no structural function.
2 Segmental retaining wall systems (SRWs) are manufactured wall systems consisting of interlocking concrete blocks that are vertically secured by an adhesive. The wall sits on a gravel base rather than a poured concrete footer. To maintain horizontal stability, SRWs use synthetic mesh fabric anchors called geogrids. These extend from the back of the wall and are buried in the backfill.
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Custom Built or Manufactured Wall?
The advantage of manufactured block wall systems, says Jeff Taphouse of Techo Bloc, is the speed of installation that comes from the efficiency of a complete system. “You don’t have to wait for a poured concrete footer to dry. You can dig, pour gravel, install the base course, and build your wall all in the same day.
That speed can translate into cost savings on labor because there is no requirement for highly skilled craftsmen.
The obvious advantage of custom-built retaining walls is creative freedom. In the hands of skilled stonemasons, there are no limitations on the design vision.
What to Expect When Retaining Wall Construction Begins
There will be dirt and lots of it. Whether the project is large or small, retaining wall and hardscape construction proceeds methodically through five phases.
The first three of those construction phases require meticulous attention to detail. The beauty and longevity of your landscaping project depend on the thoroughness of your landscape construction crew. They are building a foundation to support the colorful, living landscape that will emerge at the end.
1 Site Preparation
Crews create access to bring equipment onto the property, and they identify a staging area where they will store materials. They also take care of any demolition needed on site to create a blank canvas. This first phase can be shocking to some clients if, for example, we’ve torn out a section of fence and put what appears to be a road through their back yard. They know it’s part of the plan, but the reality can be a bit disorienting at first.
2 Excavation and Drainage
We start shaving down the grades or filling low areas to prepare for patios. We dig trenches for subsurface infrastructure: drainage, gas and electrical lines, and wall footers. We work with our subcontractors to install pipe and run cables. After county inspection, we backfill the trenches and start building.
3 Wall Building
We begin to build masonry block walls and get the sub-base ready for patios and other hardscape features. Next, we set stonework and lay pavers. After we complete this phase, we are at the halfway mark.
4 Rough Grading
We fill in any holes that we’ve created, fine-tune grades, and add soil where beds are going to be built up. We complete work on the drainage system that we started earlier. At this point, the property looks exactly as it should, but there are no plants in the ground, no mulch, no sod. It’s all dirt and stone, but it looks orderly.
5 Lights, Sound, Plants
Now the transformation happens. We bury lighting and audio cables and run irrigation. We bring in plants, install lighting fixtures, mulch the beds, and roll out sod. In a matter of days, we’ve taken this months-long job from a hardscape desert to a lush landscape.
Retaining walls are an essential part of the hardscaping portion of your landscape. Freestanding garden walls, stone retaining walls, and borders fit together with patio areas and walkways to make a complete composition and to present the flower beds and other plantings in the most flattering way.
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