When it comes to building a retaining wall like the ones you see in Edmonton’s most beautiful landscapes, there’s a lot more to it than what you see on the surface. While the form and function of the average retaining wall may seem straightforward, installing one without prior experience can set you up for more risk than reward. We spoke to landscape designer Toby Brilz for insight on the processes and considerations landscapers use on the job. Here’s how the pros install a retaining wall—and why you should consider picking up the phone before you try it yourself.
In the City of Edmonton, retaining walls over 0.6 metres in height are required to be engineered designs, requiring a permit and design draft. Professional landscape designers are not only well-aware of this, but they also have the expertise to procure the right permits and efficiently develop a reliable design. Landscaping companies are also well-versed in current bylaws that affect projects like retaining walls, including the homeowner’s liability if the retaining wall leads to accidental flooding on your property (or worse, your neighbour’s!).
Attention to Grading
When a professional landscape designer is planning a retaining wall build, they’re also considering how the wall will interact with the grading of the lot—something also regulated by the City of Edmonton.
“You can’t alter the grade along the property line slope—both have to stay,” says Toby. “We can’t put it in a situation where the slope is going to drain the water into the neighbour’s yard or totally alter the flow of water, which could result in erosion.”
The final design is engineered to direct the flow of water appropriately so that the yard and surrounding yards are not negatively impacted by the change in your landscape’s topography.
A Solid Foundation
To build a stable structure, the pros can’t simply start stacking bricks on top of your lawn. The foundation is one of the most important structural components of a retaining wall; it needs to be perfectly level and often needs to be deeper than you’d expect.
“In order to be secure, the base of a retaining wall is sometimes buried, depending on the material and how high it’ll be,” Toby explains. “So, when it’s professionally done, it’s constructed correctly for it to last a long time.”
Even a relatively short, 4-foot retaining wall can end up supporting several tonnes of soil—especially after heavy rains or the many snow-and-melt cycles Edmonton is famous for. Professionally designed retaining walls are constructed to support the materials behind them, often sloping slightly backward to counter-balance the pressure of the load.
Drainage, Drainage, Drainage!
Part of a retaining wall’s ability to support all that pressure is well-thought-out drainage, allowing water to flow through the wall rather than build up and add more weight to the soil.
“[A do-it-yourselfer] might put a retaining wall in but forget to put drainage space behind it,” says Toby. “It doesn’t matter how big the wall is; it’s good to have drainage behind it because the pressure of the earth, and sod will shift things around.”
To achieve this, landscapers will add a drain pipe or drain tile at the base of the retaining wall and backfill behind it with crushed stone or another drainage-friendly fill. This gives water an easy escape route rather than pressing up against the structure.
The Right Materials
In addition to the decorative material that will make up the outer-facing part of your retaining wall, professionals use a host of other tools and materials to ensure the wall is soundly built, correctly backfilled, and channels water appropriately. Professionals are also skilled in the usage of common retaining wall materials, such as:
- Poured concrete
- Natural stone and/or boulders
- Stone veneer
Knowing the best way to build with these materials is key to creating a long-lasting design, saving you money on materials and maintenance in the long run.
“The professionalism of the installation is also important because of how the retaining wall is going to affect you and your neighbour’s yards,” adds Toby.
Book a Landscape Design Consultation
When considering a major change to your landscape, whether it’s a retaining wall or another project, you’ve got nothing to lose and a lot to gain by calling a trusted firm in the Edmonton area. Salisbury’s reputable team of talented designers can work with you to better understand what it would mean to achieve your desired result before you move ahead with the project. Book a consult today to explore the options available for your yard!